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linux/mm/mmap.c

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treewide: Add SPDX license identifier for missed files Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-19 15:08:55 +03:00
// SPDX-License-Identifier: GPL-2.0-only
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* mm/mmap.c
*
* Written by obz.
*
mm: update my address Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-05 17:06:29 +03:00
* Address space accounting code <alan@lxorguk.ukuu.org.uk>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
mm: convert some level-less printks to pr_* printk is meant to be used with an associated log level. There are some instances of printk scattered around the mm code where the log level is missing. Add a log level and adhere to suggestions by scripts/checkpatch.pl by moving to the pr_* macros. Also add the typical pr_fmt definition so that print statements can be easily traced back to the modules where they occur, correlated one with another, etc. This will require the removal of some (now redundant) prefixes on a few print statements. Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-07 01:38:30 +04:00
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
mm/mmap: check for RLIMIT_AS before unmapping Fix a corner case for MAP_FIXED when requested mapping length is larger than rlimit for virtual memory. In such case any overlapping mappings are unmapped before we check for the limit and return ENOMEM. The check is moved before the loop that unmaps overlapping parts of existing mappings. When we are about to hit the limit (currently mapped pages + len > limit) we scan for overlapping pages and check again accounting for them. This fixes situation when userspace program expects that the previous mappings are preserved after the mmap() syscall has returned with error. (POSIX clearly states that successfull mapping shall replace any previous mappings.) This corner case was found and can be tested with LTP testcase: testcases/open_posix_testsuite/conformance/interfaces/mmap/24-2.c In this case the mmap, which is clearly over current limit, unmaps dynamic libraries and the testcase segfaults right after returning into userspace. I've also looked at the second instance of the unmapping loop in the do_brk(). The do_brk() is called from brk() syscall and from vm_brk(). The brk() syscall checks for overlapping mappings and bails out when there are any (so it can't be triggered from the brk syscall). The vm_brk() is called only from binmft handlers so it shouldn't be triggered unless binmft handler created overlapping mappings. Signed-off-by: Cyril Hrubis <chrubis@suse.cz> Reviewed-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:33 +04:00
#include <linux/kernel.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
#include <linux/slab.h>
Drop some headers from mm.h mm.h doesn't use directly anything from mutex.h and backing-dev.h, so remove them and add them back to files which need them. Cross-compile tested on many configs and archs. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 10:29:23 +04:00
#include <linux/backing-dev.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
#include <linux/mm.h>
mm: per-thread vma caching This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 02:37:25 +04:00
#include <linux/vmacache.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
#include <linux/shm.h>
#include <linux/mman.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/syscalls.h>
[PATCH] move capable() to capability.h - Move capable() from sched.h to capability.h; - Use <linux/capability.h> where capable() is used (in include/, block/, ipc/, kernel/, a few drivers/, mm/, security/, & sound/; many more drivers/ to go) Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11 23:17:46 +03:00
#include <linux/capability.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
#include <linux/init.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/personality.h>
#include <linux/security.h>
#include <linux/hugetlb.h>
shmem: get_unmapped_area align huge page Provide a shmem_get_unmapped_area method in file_operations, called at mmap time to decide the mapping address. It could be conditional on CONFIG_TRANSPARENT_HUGEPAGE, but save #ifdefs in other places by making it unconditional. shmem_get_unmapped_area() first calls the usual mm->get_unmapped_area (which we treat as a black box, highly dependent on architecture and config and executable layout). Lots of conditions, and in most cases it just goes with the address that chose; but when our huge stars are rightly aligned, yet that did not provide a suitable address, go back to ask for a larger arena, within which to align the mapping suitably. There have to be some direct calls to shmem_get_unmapped_area(), not via the file_operations: because of the way shmem_zero_setup() is called to create a shmem object late in the mmap sequence, when MAP_SHARED is requested with MAP_ANONYMOUS or /dev/zero. Though this only matters when /proc/sys/vm/shmem_huge has been set. Link: http://lkml.kernel.org/r/1466021202-61880-29-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27 01:26:15 +03:00
#include <linux/shmem_fs.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
#include <linux/profile.h>
mm: Map most files to use export.h instead of module.h The files changed within are only using the EXPORT_SYMBOL macro variants. They are not using core modular infrastructure and hence don't need module.h but only the export.h header. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-16 10:01:52 +04:00
#include <linux/export.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
#include <linux/mount.h>
#include <linux/mempolicy.h>
#include <linux/rmap.h>
mmu-notifiers: core With KVM/GFP/XPMEM there isn't just the primary CPU MMU pointing to pages. There are secondary MMUs (with secondary sptes and secondary tlbs) too. sptes in the kvm case are shadow pagetables, but when I say spte in mmu-notifier context, I mean "secondary pte". In GRU case there's no actual secondary pte and there's only a secondary tlb because the GRU secondary MMU has no knowledge about sptes and every secondary tlb miss event in the MMU always generates a page fault that has to be resolved by the CPU (this is not the case of KVM where the a secondary tlb miss will walk sptes in hardware and it will refill the secondary tlb transparently to software if the corresponding spte is present). The same way zap_page_range has to invalidate the pte before freeing the page, the spte (and secondary tlb) must also be invalidated before any page is freed and reused. Currently we take a page_count pin on every page mapped by sptes, but that means the pages can't be swapped whenever they're mapped by any spte because they're part of the guest working set. Furthermore a spte unmap event can immediately lead to a page to be freed when the pin is released (so requiring the same complex and relatively slow tlb_gather smp safe logic we have in zap_page_range and that can be avoided completely if the spte unmap event doesn't require an unpin of the page previously mapped in the secondary MMU). The mmu notifiers allow kvm/GRU/XPMEM to attach to the tsk->mm and know when the VM is swapping or freeing or doing anything on the primary MMU so that the secondary MMU code can drop sptes before the pages are freed, avoiding all page pinning and allowing 100% reliable swapping of guest physical address space. Furthermore it avoids the code that teardown the mappings of the secondary MMU, to implement a logic like tlb_gather in zap_page_range that would require many IPI to flush other cpu tlbs, for each fixed number of spte unmapped. To make an example: if what happens on the primary MMU is a protection downgrade (from writeable to wrprotect) the secondary MMU mappings will be invalidated, and the next secondary-mmu-page-fault will call get_user_pages and trigger a do_wp_page through get_user_pages if it called get_user_pages with write=1, and it'll re-establishing an updated spte or secondary-tlb-mapping on the copied page. Or it will setup a readonly spte or readonly tlb mapping if it's a guest-read, if it calls get_user_pages with write=0. This is just an example. This allows to map any page pointed by any pte (and in turn visible in the primary CPU MMU), into a secondary MMU (be it a pure tlb like GRU, or an full MMU with both sptes and secondary-tlb like the shadow-pagetable layer with kvm), or a remote DMA in software like XPMEM (hence needing of schedule in XPMEM code to send the invalidate to the remote node, while no need to schedule in kvm/gru as it's an immediate event like invalidating primary-mmu pte). At least for KVM without this patch it's impossible to swap guests reliably. And having this feature and removing the page pin allows several other optimizations that simplify life considerably. Dependencies: 1) mm_take_all_locks() to register the mmu notifier when the whole VM isn't doing anything with "mm". This allows mmu notifier users to keep track if the VM is in the middle of the invalidate_range_begin/end critical section with an atomic counter incraese in range_begin and decreased in range_end. No secondary MMU page fault is allowed to map any spte or secondary tlb reference, while the VM is in the middle of range_begin/end as any page returned by get_user_pages in that critical section could later immediately be freed without any further ->invalidate_page notification (invalidate_range_begin/end works on ranges and ->invalidate_page isn't called immediately before freeing the page). To stop all page freeing and pagetable overwrites the mmap_sem must be taken in write mode and all other anon_vma/i_mmap locks must be taken too. 2) It'd be a waste to add branches in the VM if nobody could possibly run KVM/GRU/XPMEM on the kernel, so mmu notifiers will only enabled if CONFIG_KVM=m/y. In the current kernel kvm won't yet take advantage of mmu notifiers, but this already allows to compile a KVM external module against a kernel with mmu notifiers enabled and from the next pull from kvm.git we'll start using them. And GRU/XPMEM will also be able to continue the development by enabling KVM=m in their config, until they submit all GRU/XPMEM GPLv2 code to the mainline kernel. Then they can also enable MMU_NOTIFIERS in the same way KVM does it (even if KVM=n). This guarantees nobody selects MMU_NOTIFIER=y if KVM and GRU and XPMEM are all =n. The mmu_notifier_register call can fail because mm_take_all_locks may be interrupted by a signal and return -EINTR. Because mmu_notifier_reigster is used when a driver startup, a failure can be gracefully handled. Here an example of the change applied to kvm to register the mmu notifiers. Usually when a driver startups other allocations are required anyway and -ENOMEM failure paths exists already. struct kvm *kvm_arch_create_vm(void) { struct kvm *kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL); + int err; if (!kvm) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&kvm->arch.active_mmu_pages); + kvm->arch.mmu_notifier.ops = &kvm_mmu_notifier_ops; + err = mmu_notifier_register(&kvm->arch.mmu_notifier, current->mm); + if (err) { + kfree(kvm); + return ERR_PTR(err); + } + return kvm; } mmu_notifier_unregister returns void and it's reliable. The patch also adds a few needed but missing includes that would prevent kernel to compile after these changes on non-x86 archs (x86 didn't need them by luck). [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix mm/filemap_xip.c build] [akpm@linux-foundation.org: fix mm/mmu_notifier.c build] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:29 +04:00
#include <linux/mmu_notifier.h>
mm: catch memory commitment underflow Print a warning (if CONFIG_DEBUG_VM=y) when memory commitment becomes too negative. This shouldn't happen any more - the previous two patches fixed the committed_as underflow issues. [akpm@linux-foundation.org: use VM_WARN_ONCE, per Dave] Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-07 03:06:36 +04:00
#include <linux/mmdebug.h>
perf: Do the big rename: Performance Counters -> Performance Events Bye-bye Performance Counters, welcome Performance Events! In the past few months the perfcounters subsystem has grown out its initial role of counting hardware events, and has become (and is becoming) a much broader generic event enumeration, reporting, logging, monitoring, analysis facility. Naming its core object 'perf_counter' and naming the subsystem 'perfcounters' has become more and more of a misnomer. With pending code like hw-breakpoints support the 'counter' name is less and less appropriate. All in one, we've decided to rename the subsystem to 'performance events' and to propagate this rename through all fields, variables and API names. (in an ABI compatible fashion) The word 'event' is also a bit shorter than 'counter' - which makes it slightly more convenient to write/handle as well. Thanks goes to Stephane Eranian who first observed this misnomer and suggested a rename. User-space tooling and ABI compatibility is not affected - this patch should be function-invariant. (Also, defconfigs were not touched to keep the size down.) This patch has been generated via the following script: FILES=$(find * -type f | grep -vE 'oprofile|[^K]config') sed -i \ -e 's/PERF_EVENT_/PERF_RECORD_/g' \ -e 's/PERF_COUNTER/PERF_EVENT/g' \ -e 's/perf_counter/perf_event/g' \ -e 's/nb_counters/nb_events/g' \ -e 's/swcounter/swevent/g' \ -e 's/tpcounter_event/tp_event/g' \ $FILES for N in $(find . -name perf_counter.[ch]); do M=$(echo $N | sed 's/perf_counter/perf_event/g') mv $N $M done FILES=$(find . -name perf_event.*) sed -i \ -e 's/COUNTER_MASK/REG_MASK/g' \ -e 's/COUNTER/EVENT/g' \ -e 's/\<event\>/event_id/g' \ -e 's/counter/event/g' \ -e 's/Counter/Event/g' \ $FILES ... to keep it as correct as possible. This script can also be used by anyone who has pending perfcounters patches - it converts a Linux kernel tree over to the new naming. We tried to time this change to the point in time where the amount of pending patches is the smallest: the end of the merge window. Namespace clashes were fixed up in a preparatory patch - and some stylistic fallout will be fixed up in a subsequent patch. ( NOTE: 'counters' are still the proper terminology when we deal with hardware registers - and these sed scripts are a bit over-eager in renaming them. I've undone some of that, but in case there's something left where 'counter' would be better than 'event' we can undo that on an individual basis instead of touching an otherwise nicely automated patch. ) Suggested-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-21 14:02:48 +04:00
#include <linux/perf_event.h>
audit mmap Normal syscall audit doesn't catch 5th argument of syscall. It also doesn't catch the contents of userland structures pointed to be syscall argument, so for both old and new mmap(2) ABI it doesn't record the descriptor we are mapping. For old one it also misses flags. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-30 10:54:44 +04:00
#include <linux/audit.h>
thp: khugepaged vma merge register in khugepaged if the vma grows. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-14 02:46:59 +03:00
#include <linux/khugepaged.h>
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 13:26:42 +04:00
#include <linux/uprobes.h>
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
#include <linux/rbtree_augmented.h>
mm: reinititalise user and admin reserves if memory is added or removed Alter the admin and user reserves of the previous patches in this series when memory is added or removed. If memory is added and the reserves have been eliminated or increased above the default max, then we'll trust the admin. If memory is removed and there isn't enough free memory, then we need to reset the reserves. Otherwise keep the reserve set by the admin. The reserve reset code is the same as the reserve initialization code. I tested hot addition and removal by triggering it via sysfs. The reserves shrunk when they were set high and memory was removed. They were reset higher when memory was added again. [akpm@linux-foundation.org: use register_hotmemory_notifier()] [akpm@linux-foundation.org: init_user_reserve() and init_admin_reserve can no longer be __meminit] [fengguang.wu@intel.com: make init_reserve_notifier() static] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:12 +04:00
#include <linux/notifier.h>
#include <linux/memory.h>
mm: convert some level-less printks to pr_* printk is meant to be used with an associated log level. There are some instances of printk scattered around the mm code where the log level is missing. Add a log level and adhere to suggestions by scripts/checkpatch.pl by moving to the pr_* macros. Also add the typical pr_fmt definition so that print statements can be easily traced back to the modules where they occur, correlated one with another, etc. This will require the removal of some (now redundant) prefixes on a few print statements. Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-07 01:38:30 +04:00
#include <linux/printk.h>
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
#include <linux/userfaultfd_k.h>
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 03:57:43 +03:00
#include <linux/moduleparam.h>
mm/core, x86/mm/pkeys: Add execute-only protection keys support Protection keys provide new page-based protection in hardware. But, they have an interesting attribute: they only affect data accesses and never affect instruction fetches. That means that if we set up some memory which is set as "access-disabled" via protection keys, we can still execute from it. This patch uses protection keys to set up mappings to do just that. If a user calls: mmap(..., PROT_EXEC); or mprotect(ptr, sz, PROT_EXEC); (note PROT_EXEC-only without PROT_READ/WRITE), the kernel will notice this, and set a special protection key on the memory. It also sets the appropriate bits in the Protection Keys User Rights (PKRU) register so that the memory becomes unreadable and unwritable. I haven't found any userspace that does this today. With this facility in place, we expect userspace to move to use it eventually. Userspace _could_ start doing this today. Any PROT_EXEC calls get converted to PROT_READ inside the kernel, and would transparently be upgraded to "true" PROT_EXEC with this code. IOW, userspace never has to do any PROT_EXEC runtime detection. This feature provides enhanced protection against leaking executable memory contents. This helps thwart attacks which are attempting to find ROP gadgets on the fly. But, the security provided by this approach is not comprehensive. The PKRU register which controls access permissions is a normal user register writable from unprivileged userspace. An attacker who can execute the 'wrpkru' instruction can easily disable the protection provided by this feature. The protection key that is used for execute-only support is permanently dedicated at compile time. This is fine for now because there is currently no API to set a protection key other than this one. Despite there being a constant PKRU value across the entire system, we do not set it unless this feature is in use in a process. That is to preserve the PKRU XSAVE 'init state', which can lead to faster context switches. PKRU *is* a user register and the kernel is modifying it. That means that code doing: pkru = rdpkru() pkru |= 0x100; mmap(..., PROT_EXEC); wrpkru(pkru); could lose the bits in PKRU that enforce execute-only permissions. To avoid this, we suggest avoiding ever calling mmap() or mprotect() when the PKRU value is expected to be unstable. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Gang <gang.chen.5i5j@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave@sr71.net> Cc: David Hildenbrand <dahi@linux.vnet.ibm.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Piotr Kwapulinski <kwapulinski.piotr@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Vladimir Murzin <vladimir.murzin@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: keescook@google.com Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210240.CB4BB5CA@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-13 00:02:40 +03:00
#include <linux/pkeys.h>
mm: oom: let oom_reap_task and exit_mmap run concurrently This is purely required because exit_aio() may block and exit_mmap() may never start, if the oom_reap_task cannot start running on a mm with mm_users == 0. At the same time if the OOM reaper doesn't wait at all for the memory of the current OOM candidate to be freed by exit_mmap->unmap_vmas, it would generate a spurious OOM kill. If it wasn't because of the exit_aio or similar blocking functions in the last mmput, it would be enough to change the oom_reap_task() in the case it finds mm_users == 0, to wait for a timeout or to wait for __mmput to set MMF_OOM_SKIP itself, but it's not just exit_mmap the problem here so the concurrency of exit_mmap and oom_reap_task is apparently warranted. It's a non standard runtime, exit_mmap() runs without mmap_sem, and oom_reap_task runs with the mmap_sem for reading as usual (kind of MADV_DONTNEED). The race between the two is solved with a combination of tsk_is_oom_victim() (serialized by task_lock) and MMF_OOM_SKIP (serialized by a dummy down_write/up_write cycle on the same lines of the ksm_exit method). If the oom_reap_task() may be running concurrently during exit_mmap, exit_mmap will wait it to finish in down_write (before taking down mm structures that would make the oom_reap_task fail with use after free). If exit_mmap comes first, oom_reap_task() will skip the mm if MMF_OOM_SKIP is already set and in turn all memory is already freed and furthermore the mm data structures may already have been taken down by free_pgtables. [aarcange@redhat.com: incremental one liner] Link: http://lkml.kernel.org/r/20170726164319.GC29716@redhat.com [rientjes@google.com: remove unused mmput_async] Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1708141733130.50317@chino.kir.corp.google.com [aarcange@redhat.com: microoptimization] Link: http://lkml.kernel.org/r/20170817171240.GB5066@redhat.com Link: http://lkml.kernel.org/r/20170726162912.GA29716@redhat.com Fixes: 26db62f179d1 ("oom: keep mm of the killed task available") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: David Rientjes <rientjes@google.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-07 02:25:00 +03:00
#include <linux/oom.h>
coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping The core dumping code has always run without holding the mmap_sem for writing, despite that is the only way to ensure that the entire vma layout will not change from under it. Only using some signal serialization on the processes belonging to the mm is not nearly enough. This was pointed out earlier. For example in Hugh's post from Jul 2017: https://lkml.kernel.org/r/alpine.LSU.2.11.1707191716030.2055@eggly.anvils "Not strictly relevant here, but a related note: I was very surprised to discover, only quite recently, how handle_mm_fault() may be called without down_read(mmap_sem) - when core dumping. That seems a misguided optimization to me, which would also be nice to correct" In particular because the growsdown and growsup can move the vm_start/vm_end the various loops the core dump does around the vma will not be consistent if page faults can happen concurrently. Pretty much all users calling mmget_not_zero()/get_task_mm() and then taking the mmap_sem had the potential to introduce unexpected side effects in the core dumping code. Adding mmap_sem for writing around the ->core_dump invocation is a viable long term fix, but it requires removing all copy user and page faults and to replace them with get_dump_page() for all binary formats which is not suitable as a short term fix. For the time being this solution manually covers the places that can confuse the core dump either by altering the vma layout or the vma flags while it runs. Once ->core_dump runs under mmap_sem for writing the function mmget_still_valid() can be dropped. Allowing mmap_sem protected sections to run in parallel with the coredump provides some minor parallelism advantage to the swapoff code (which seems to be safe enough by never mangling any vma field and can keep doing swapins in parallel to the core dumping) and to some other corner case. In order to facilitate the backporting I added "Fixes: 86039bd3b4e6" however the side effect of this same race condition in /proc/pid/mem should be reproducible since before 2.6.12-rc2 so I couldn't add any other "Fixes:" because there's no hash beyond the git genesis commit. Because find_extend_vma() is the only location outside of the process context that could modify the "mm" structures under mmap_sem for reading, by adding the mmget_still_valid() check to it, all other cases that take the mmap_sem for reading don't need the new check after mmget_not_zero()/get_task_mm(). The expand_stack() in page fault context also doesn't need the new check, because all tasks under core dumping are frozen. Link: http://lkml.kernel.org/r/20190325224949.11068-1-aarcange@redhat.com Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Jann Horn <jannh@google.com> Suggested-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jann Horn <jannh@google.com> Acked-by: Jason Gunthorpe <jgg@mellanox.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-19 03:50:52 +03:00
#include <linux/sched/mm.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
Replace <asm/uaccess.h> with <linux/uaccess.h> globally This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 22:46:01 +03:00
#include <linux/uaccess.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
#include <asm/cacheflush.h>
#include <asm/tlb.h>
[PATCH] x86: PARAVIRT: add hooks to intercept mm creation and destruction Add hooks to allow a paravirt implementation to track the lifetime of an mm. Paravirtualization requires three hooks, but only two are needed in common code. They are: arch_dup_mmap, which is called when a new mmap is created at fork arch_exit_mmap, which is called when the last process reference to an mm is dropped, which typically happens on exit and exec. The third hook is activate_mm, which is called from the arch-specific activate_mm() macro/function, and so doesn't need stub versions for other architectures. It's called when an mm is first used. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: linux-arch@vger.kernel.org Cc: James Bottomley <James.Bottomley@SteelEye.com> Acked-by: Ingo Molnar <mingo@elte.hu>
2007-05-02 21:27:14 +04:00
#include <asm/mmu_context.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: mmap: add trace point of vm_unmapped_area Even on 64 bit kernel, the mmap failure can happen for a 32 bit task. Virtual memory space shortage of a task on mmap is reported to userspace as -ENOMEM. It can be confused as physical memory shortage of overall system. The vm_unmapped_area can be called to by some drivers or other kernel core system like filesystem. In my platform, GPU driver calls to vm_unmapped_area and the driver returns -ENOMEM even in GPU side shortage. It can be hard to distinguish which code layer returns the -ENOMEM. Create mmap trace file and add trace point of vm_unmapped_area. i.e.) 277.156599: vm_unmapped_area: addr=77e0d03000 err=0 total_vm=0x17014b flags=0x1 len=0x400000 lo=0x8000 hi=0x7878c27000 mask=0x0 ofs=0x1 342.838740: vm_unmapped_area: addr=0 err=-12 total_vm=0xffb08 flags=0x0 len=0x100000 lo=0x40000000 hi=0xfffff000 mask=0x0 ofs=0x22 [akpm@linux-foundation.org: prefix address printk with 0x, per Matthew] Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200320055823.27089-3-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:13 +03:00
#define CREATE_TRACE_POINTS
#include <trace/events/mmap.h>
mm: remove double indirection on tlb parameter to free_pgd_range() & Co The double indirection here is not needed anywhere and hence (at least) confusing. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Acked-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 08:27:10 +04:00
#include "internal.h"
[PATCH] IA64,sparc: local DoS with corrupted ELFs This prevents cross-region mappings on IA64 and SPARC which could lead to system crash. They were correctly trapped for normal mmap() calls, but not for the kernel internal calls generated by executable loading. This code just moves the architecture-specific cross-region checks into an arch-specific "arch_mmap_check()" macro, and defines that for the architectures that needed it (ia64, sparc and sparc64). Architectures that don't have any special requirements can just ignore the new cross-region check, since the mmap() code will just notice on its own when the macro isn't defined. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Kirill Korotaev <dev@openvz.org> Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> [ Cleaned up to not affect architectures that don't need it ] Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-07 14:17:04 +04:00
#ifndef arch_mmap_check
#define arch_mmap_check(addr, len, flags) (0)
#endif
mm: mmap: add new /proc tunable for mmap_base ASLR Address Space Layout Randomization (ASLR) provides a barrier to exploitation of user-space processes in the presence of security vulnerabilities by making it more difficult to find desired code/data which could help an attack. This is done by adding a random offset to the location of regions in the process address space, with a greater range of potential offset values corresponding to better protection/a larger search-space for brute force, but also to greater potential for fragmentation. The offset added to the mmap_base address, which provides the basis for the majority of the mappings for a process, is set once on process exec in arch_pick_mmap_layout() and is done via hard-coded per-arch values, which reflect, hopefully, the best compromise for all systems. The trade-off between increased entropy in the offset value generation and the corresponding increased variability in address space fragmentation is not absolute, however, and some platforms may tolerate higher amounts of entropy. This patch introduces both new Kconfig values and a sysctl interface which may be used to change the amount of entropy used for offset generation on a system. The direct motivation for this change was in response to the libstagefright vulnerabilities that affected Android, specifically to information provided by Google's project zero at: http://googleprojectzero.blogspot.com/2015/09/stagefrightened.html The attack presented therein, by Google's project zero, specifically targeted the limited randomness used to generate the offset added to the mmap_base address in order to craft a brute-force-based attack. Concretely, the attack was against the mediaserver process, which was limited to respawning every 5 seconds, on an arm device. The hard-coded 8 bits used resulted in an average expected success rate of defeating the mmap ASLR after just over 10 minutes (128 tries at 5 seconds a piece). With this patch, and an accompanying increase in the entropy value to 16 bits, the same attack would take an average expected time of over 45 hours (32768 tries), which makes it both less feasible and more likely to be noticed. The introduced Kconfig and sysctl options are limited by per-arch minimum and maximum values, the minimum of which was chosen to match the current hard-coded value and the maximum of which was chosen so as to give the greatest flexibility without generating an invalid mmap_base address, generally a 3-4 bits less than the number of bits in the user-space accessible virtual address space. When decided whether or not to change the default value, a system developer should consider that mmap_base address could be placed anywhere up to 2^(value) bits away from the non-randomized location, which would introduce variable-sized areas above and below the mmap_base address such that the maximum vm_area_struct size may be reduced, preventing very large allocations. This patch (of 4): ASLR only uses as few as 8 bits to generate the random offset for the mmap base address on 32 bit architectures. This value was chosen to prevent a poorly chosen value from dividing the address space in such a way as to prevent large allocations. This may not be an issue on all platforms. Allow the specification of a minimum number of bits so that platforms desiring greater ASLR protection may determine where to place the trade-off. Signed-off-by: Daniel Cashman <dcashman@google.com> Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Don Zickus <dzickus@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Rientjes <rientjes@google.com> Cc: Mark Salyzyn <salyzyn@android.com> Cc: Jeff Vander Stoep <jeffv@google.com> Cc: Nick Kralevich <nnk@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Borislav Petkov <bp@suse.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:19:53 +03:00
#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN;
const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX;
int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS;
#endif
#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
const int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN;
const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX;
int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS;
#endif
mm: enable RLIMIT_DATA by default with workaround for valgrind Since commit 84638335900f ("mm: rework virtual memory accounting") RLIMIT_DATA limits both brk() and private mmap() but this's disabled by default because of incompatibility with older versions of valgrind. Valgrind always set limit to zero and fails if RLIMIT_DATA is enabled. Fortunately it changes only rlim_cur and keeps rlim_max for reverting limit back when needed. This patch checks current usage also against rlim_max if rlim_cur is zero. This is safe because task anyway can increase rlim_cur up to rlim_max. Size of brk is still checked against rlim_cur, so this part is completely compatible - zero rlim_cur forbids brk() but allows private mmap(). Link: http://lkml.kernel.org/r/56A28613.5070104@de.ibm.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-21 02:57:45 +03:00
static bool ignore_rlimit_data;
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 03:57:43 +03:00
core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644);
mm: mmap: add new /proc tunable for mmap_base ASLR Address Space Layout Randomization (ASLR) provides a barrier to exploitation of user-space processes in the presence of security vulnerabilities by making it more difficult to find desired code/data which could help an attack. This is done by adding a random offset to the location of regions in the process address space, with a greater range of potential offset values corresponding to better protection/a larger search-space for brute force, but also to greater potential for fragmentation. The offset added to the mmap_base address, which provides the basis for the majority of the mappings for a process, is set once on process exec in arch_pick_mmap_layout() and is done via hard-coded per-arch values, which reflect, hopefully, the best compromise for all systems. The trade-off between increased entropy in the offset value generation and the corresponding increased variability in address space fragmentation is not absolute, however, and some platforms may tolerate higher amounts of entropy. This patch introduces both new Kconfig values and a sysctl interface which may be used to change the amount of entropy used for offset generation on a system. The direct motivation for this change was in response to the libstagefright vulnerabilities that affected Android, specifically to information provided by Google's project zero at: http://googleprojectzero.blogspot.com/2015/09/stagefrightened.html The attack presented therein, by Google's project zero, specifically targeted the limited randomness used to generate the offset added to the mmap_base address in order to craft a brute-force-based attack. Concretely, the attack was against the mediaserver process, which was limited to respawning every 5 seconds, on an arm device. The hard-coded 8 bits used resulted in an average expected success rate of defeating the mmap ASLR after just over 10 minutes (128 tries at 5 seconds a piece). With this patch, and an accompanying increase in the entropy value to 16 bits, the same attack would take an average expected time of over 45 hours (32768 tries), which makes it both less feasible and more likely to be noticed. The introduced Kconfig and sysctl options are limited by per-arch minimum and maximum values, the minimum of which was chosen to match the current hard-coded value and the maximum of which was chosen so as to give the greatest flexibility without generating an invalid mmap_base address, generally a 3-4 bits less than the number of bits in the user-space accessible virtual address space. When decided whether or not to change the default value, a system developer should consider that mmap_base address could be placed anywhere up to 2^(value) bits away from the non-randomized location, which would introduce variable-sized areas above and below the mmap_base address such that the maximum vm_area_struct size may be reduced, preventing very large allocations. This patch (of 4): ASLR only uses as few as 8 bits to generate the random offset for the mmap base address on 32 bit architectures. This value was chosen to prevent a poorly chosen value from dividing the address space in such a way as to prevent large allocations. This may not be an issue on all platforms. Allow the specification of a minimum number of bits so that platforms desiring greater ASLR protection may determine where to place the trade-off. Signed-off-by: Daniel Cashman <dcashman@google.com> Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Don Zickus <dzickus@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Rientjes <rientjes@google.com> Cc: Mark Salyzyn <salyzyn@android.com> Cc: Jeff Vander Stoep <jeffv@google.com> Cc: Nick Kralevich <nnk@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Borislav Petkov <bp@suse.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:19:53 +03:00
[PATCH] freepgt: free_pgtables use vma list Recent woes with some arches needing their own pgd_addr_end macro; and 4-level clear_page_range regression since 2.6.10's clear_page_tables; and its long-standing well-known inefficiency in searching throughout the higher-level page tables for those few entries to clear and free: all can be blamed on ignoring the list of vmas when we free page tables. Replace exit_mmap's clear_page_range of the total user address space by free_pgtables operating on the mm's vma list; unmap_region use it in the same way, giving floor and ceiling beyond which it may not free tables. This brings lmbench fork/exec/sh numbers back to 2.6.10 (unless preempt is enabled, in which case latency fixes spoil unmap_vmas throughput). Beware: the do_mmap_pgoff driver failure case must now use unmap_region instead of zap_page_range, since a page table might have been allocated, and can only be freed while it is touched by some vma. Move free_pgtables from mmap.c to memory.c, where its lower levels are adapted from the clear_page_range levels. (Most of free_pgtables' old code was actually for a non-existent case, prev not properly set up, dating from before hch gave us split_vma.) Pass mmu_gather** in the public interfaces, since we might want to add latency lockdrops later; but no attempt to do so yet, going by vma should itself reduce latency. But what if is_hugepage_only_range? Those ia64 and ppc64 cases need careful examination: put that off until a later patch of the series. What of x86_64's 32bit vdso page __map_syscall32 maps outside any vma? And the range to sparc64's flush_tlb_pgtables? It's less clear to me now that we need to do more than is done here - every PMD_SIZE ever occupied will be flushed, do we really have to flush every PGDIR_SIZE ever partially occupied? A shame to complicate it unnecessarily. Special thanks to David Miller for time spent repairing my ceilings. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:15 +04:00
static void unmap_region(struct mm_struct *mm,
struct vm_area_struct *vma, struct vm_area_struct *prev,
unsigned long start, unsigned long end);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* description of effects of mapping type and prot in current implementation.
* this is due to the limited x86 page protection hardware. The expected
* behavior is in parens:
*
* map_type prot
* PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
* MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
* w: (no) no w: (no) no w: (yes) yes w: (no) no
* x: (no) no x: (no) yes x: (no) yes x: (yes) yes
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
*
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
* MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
* w: (no) no w: (no) no w: (copy) copy w: (no) no
* x: (no) no x: (no) yes x: (no) yes x: (yes) yes
*/
mm/mmap.c: mark protection_map as __ro_after_init The protection map is only modified by per-arch init code so it can be protected from writes after the init code runs. This change was extracted from PaX where it's part of KERNEXEC. Link: http://lkml.kernel.org/r/20170510174441.26163-1-danielmicay@gmail.com Signed-off-by: Daniel Micay <danielmicay@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-07 01:36:47 +03:00
pgprot_t protection_map[16] __ro_after_init = {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
__P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
};
x86/pti: Filter at vma->vm_page_prot population commit ce9962bf7e22bb3891655c349faff618922d4a73 0day reported warnings at boot on 32-bit systems without NX support: attempted to set unsupported pgprot: 8000000000000025 bits: 8000000000000000 supported: 7fffffffffffffff WARNING: CPU: 0 PID: 1 at arch/x86/include/asm/pgtable.h:540 handle_mm_fault+0xfc1/0xfe0: check_pgprot at arch/x86/include/asm/pgtable.h:535 (inlined by) pfn_pte at arch/x86/include/asm/pgtable.h:549 (inlined by) do_anonymous_page at mm/memory.c:3169 (inlined by) handle_pte_fault at mm/memory.c:3961 (inlined by) __handle_mm_fault at mm/memory.c:4087 (inlined by) handle_mm_fault at mm/memory.c:4124 The problem is that due to the recent commit which removed auto-massaging of page protections, filtering page permissions at PTE creation time is not longer done, so vma->vm_page_prot is passed unfiltered to PTE creation. Filter the page protections before they are installed in vma->vm_page_prot. Fixes: fb43d6cb91 ("x86/mm: Do not auto-massage page protections") Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: linux-mm@kvack.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Nadav Amit <namit@vmware.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Link: https://lkml.kernel.org/r/20180420222028.99D72858@viggo.jf.intel.com
2018-04-21 01:20:28 +03:00
#ifndef CONFIG_ARCH_HAS_FILTER_PGPROT
static inline pgprot_t arch_filter_pgprot(pgprot_t prot)
{
return prot;
}
#endif
[AGPGART] remove private page protection map AGP keeps its own copy of the protection_map, upcoming DRM changes will also require access to this map from modules. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Dave Airlie <airlied@linux.ie> Signed-off-by: Dave Jones <davej@redhat.com>
2006-07-27 00:39:49 +04:00
pgprot_t vm_get_page_prot(unsigned long vm_flags)
{
x86/pti: Filter at vma->vm_page_prot population commit ce9962bf7e22bb3891655c349faff618922d4a73 0day reported warnings at boot on 32-bit systems without NX support: attempted to set unsupported pgprot: 8000000000000025 bits: 8000000000000000 supported: 7fffffffffffffff WARNING: CPU: 0 PID: 1 at arch/x86/include/asm/pgtable.h:540 handle_mm_fault+0xfc1/0xfe0: check_pgprot at arch/x86/include/asm/pgtable.h:535 (inlined by) pfn_pte at arch/x86/include/asm/pgtable.h:549 (inlined by) do_anonymous_page at mm/memory.c:3169 (inlined by) handle_pte_fault at mm/memory.c:3961 (inlined by) __handle_mm_fault at mm/memory.c:4087 (inlined by) handle_mm_fault at mm/memory.c:4124 The problem is that due to the recent commit which removed auto-massaging of page protections, filtering page permissions at PTE creation time is not longer done, so vma->vm_page_prot is passed unfiltered to PTE creation. Filter the page protections before they are installed in vma->vm_page_prot. Fixes: fb43d6cb91 ("x86/mm: Do not auto-massage page protections") Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: linux-mm@kvack.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Nadav Amit <namit@vmware.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Link: https://lkml.kernel.org/r/20180420222028.99D72858@viggo.jf.intel.com
2018-04-21 01:20:28 +03:00
pgprot_t ret = __pgprot(pgprot_val(protection_map[vm_flags &
mm: Allow architectures to define additional protection bits This patch allows architectures to define functions to deal with additional protections bits for mmap() and mprotect(). arch_calc_vm_prot_bits() maps additonal protection bits to vm_flags arch_vm_get_page_prot() maps additional vm_flags to the vma's vm_page_prot arch_validate_prot() checks for valid values of the protection bits Note: vm_get_page_prot() is now pretty ugly, but the generated code should be identical for architectures that don't define additional protection bits. Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-07-07 18:28:51 +04:00
(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
pgprot_val(arch_vm_get_page_prot(vm_flags)));
x86/pti: Filter at vma->vm_page_prot population commit ce9962bf7e22bb3891655c349faff618922d4a73 0day reported warnings at boot on 32-bit systems without NX support: attempted to set unsupported pgprot: 8000000000000025 bits: 8000000000000000 supported: 7fffffffffffffff WARNING: CPU: 0 PID: 1 at arch/x86/include/asm/pgtable.h:540 handle_mm_fault+0xfc1/0xfe0: check_pgprot at arch/x86/include/asm/pgtable.h:535 (inlined by) pfn_pte at arch/x86/include/asm/pgtable.h:549 (inlined by) do_anonymous_page at mm/memory.c:3169 (inlined by) handle_pte_fault at mm/memory.c:3961 (inlined by) __handle_mm_fault at mm/memory.c:4087 (inlined by) handle_mm_fault at mm/memory.c:4124 The problem is that due to the recent commit which removed auto-massaging of page protections, filtering page permissions at PTE creation time is not longer done, so vma->vm_page_prot is passed unfiltered to PTE creation. Filter the page protections before they are installed in vma->vm_page_prot. Fixes: fb43d6cb91 ("x86/mm: Do not auto-massage page protections") Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: linux-mm@kvack.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Nadav Amit <namit@vmware.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Link: https://lkml.kernel.org/r/20180420222028.99D72858@viggo.jf.intel.com
2018-04-21 01:20:28 +03:00
return arch_filter_pgprot(ret);
[AGPGART] remove private page protection map AGP keeps its own copy of the protection_map, upcoming DRM changes will also require access to this map from modules. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Dave Airlie <airlied@linux.ie> Signed-off-by: Dave Jones <davej@redhat.com>
2006-07-27 00:39:49 +04:00
}
EXPORT_SYMBOL(vm_get_page_prot);
mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:55:46 +04:00
static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)
{
return pgprot_modify(oldprot, vm_get_page_prot(vm_flags));
}
/* Update vma->vm_page_prot to reflect vma->vm_flags. */
void vma_set_page_prot(struct vm_area_struct *vma)
{
unsigned long vm_flags = vma->vm_flags;
mm: vm_page_prot: update with WRITE_ONCE/READ_ONCE vma->vm_page_prot is read lockless from the rmap_walk, it may be updated concurrently and this prevents the risk of reading intermediate values. Link: http://lkml.kernel.org/r/1474660305-19222-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:22 +03:00
pgprot_t vm_page_prot;
mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:55:46 +04:00
mm: vm_page_prot: update with WRITE_ONCE/READ_ONCE vma->vm_page_prot is read lockless from the rmap_walk, it may be updated concurrently and this prevents the risk of reading intermediate values. Link: http://lkml.kernel.org/r/1474660305-19222-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:22 +03:00
vm_page_prot = vm_pgprot_modify(vma->vm_page_prot, vm_flags);
if (vma_wants_writenotify(vma, vm_page_prot)) {
mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:55:46 +04:00
vm_flags &= ~VM_SHARED;
mm: vm_page_prot: update with WRITE_ONCE/READ_ONCE vma->vm_page_prot is read lockless from the rmap_walk, it may be updated concurrently and this prevents the risk of reading intermediate values. Link: http://lkml.kernel.org/r/1474660305-19222-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:22 +03:00
vm_page_prot = vm_pgprot_modify(vm_page_prot, vm_flags);
mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:55:46 +04:00
}
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
/* remove_protection_ptes reads vma->vm_page_prot without mmap_lock */
mm: vm_page_prot: update with WRITE_ONCE/READ_ONCE vma->vm_page_prot is read lockless from the rmap_walk, it may be updated concurrently and this prevents the risk of reading intermediate values. Link: http://lkml.kernel.org/r/1474660305-19222-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:22 +03:00
WRITE_ONCE(vma->vm_page_prot, vm_page_prot);
mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:55:46 +04:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
mm: convert i_mmap_mutex to rwsem The i_mmap_mutex is a close cousin of the anon vma lock, both protecting similar data, one for file backed pages and the other for anon memory. To this end, this lock can also be a rwsem. In addition, there are some important opportunities to share the lock when there are no tree modifications. This conversion is straightforward. For now, all users take the write lock. [sfr@canb.auug.org.au: update fremap.c] Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:54:24 +03:00
* Requires inode->i_mapping->i_mmap_rwsem
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
static void __remove_shared_vm_struct(struct vm_area_struct *vma,
struct file *file, struct address_space *mapping)
{
if (vma->vm_flags & VM_DENYWRITE)
mm/mmap.c: use helper function allow_write_access() in __remove_shared_vm_struct() In commit 1da177e4c3f4 ("Linux-2.6.12-rc2"), the helper allow_write_access came with the atomic_inc operation of the i_writecount field in the func __remove_shared_vm_struct(). But it forgot to use this helper function. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200921115814.39680-1-linmiaohe@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:54:14 +03:00
allow_write_access(file);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (vma->vm_flags & VM_SHARED)
mm: allow drivers to prevent new writable mappings This patch (of 6): The i_mmap_writable field counts existing writable mappings of an address_space. To allow drivers to prevent new writable mappings, make this counter signed and prevent new writable mappings if it is negative. This is modelled after i_writecount and DENYWRITE. This will be required by the shmem-sealing infrastructure to prevent any new writable mappings after the WRITE seal has been set. In case there exists a writable mapping, this operation will fail with EBUSY. Note that we rely on the fact that iff you already own a writable mapping, you can increase the counter without using the helpers. This is the same that we do for i_writecount. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ryan Lortie <desrt@desrt.ca> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <zonque@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-09 01:25:25 +04:00
mapping_unmap_writable(mapping);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
flush_dcache_mmap_lock(mapping);
rmap: drop support of non-linear mappings We don't create non-linear mappings anymore. Let's drop code which handles them in rmap. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:59 +03:00
vma_interval_tree_remove(vma, &mapping->i_mmap);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
flush_dcache_mmap_unlock(mapping);
}
/*
mm: replace vma prio_tree with an interval tree Implement an interval tree as a replacement for the VMA prio_tree. The algorithms are similar to lib/interval_tree.c; however that code can't be directly reused as the interval endpoints are not explicitly stored in the VMA. So instead, the common algorithm is moved into a template and the details (node type, how to get interval endpoints from the node, etc) are filled in using the C preprocessor. Once the interval tree functions are available, using them as a replacement to the VMA prio tree is a relatively simple, mechanical job. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:25 +04:00
* Unlink a file-based vm structure from its interval tree, to hide
[PATCH] mm: unlink_file_vma, remove_vma Divide remove_vm_struct into two parts: first anon_vma_unlink plus unlink_file_vma, to unlink the vma from the list and tree by which rmap or vmtruncate might find it; then remove_vma to close, fput and free. The intention here is to do the anon_vma_unlink and unlink_file_vma earlier, in free_pgtables before freeing any page tables: so we can be sure that any page tables traversed by rmap and vmtruncate are stable (and other, ordinary cases are stabilized by holding mmap_sem). This will be crucial to traversing pgd,pud,pmd without page_table_lock. But testing the split-out patch showed that lifting the page_table_lock is symbiotically necessary to make this change - the lock ordering is wrong to move those unlinks into free_pgtables while it's under ptlock. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:57 +03:00
* vma from rmap and vmtruncate before freeing its page tables.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
[PATCH] mm: unlink_file_vma, remove_vma Divide remove_vm_struct into two parts: first anon_vma_unlink plus unlink_file_vma, to unlink the vma from the list and tree by which rmap or vmtruncate might find it; then remove_vma to close, fput and free. The intention here is to do the anon_vma_unlink and unlink_file_vma earlier, in free_pgtables before freeing any page tables: so we can be sure that any page tables traversed by rmap and vmtruncate are stable (and other, ordinary cases are stabilized by holding mmap_sem). This will be crucial to traversing pgd,pud,pmd without page_table_lock. But testing the split-out patch showed that lifting the page_table_lock is symbiotically necessary to make this change - the lock ordering is wrong to move those unlinks into free_pgtables while it's under ptlock. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:57 +03:00
void unlink_file_vma(struct vm_area_struct *vma)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
struct file *file = vma->vm_file;
if (file) {
struct address_space *mapping = file->f_mapping;
mm: use new helper functions around the i_mmap_mutex Convert all open coded mutex_lock/unlock calls to the i_mmap_[lock/unlock]_write() helpers. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:54:21 +03:00
i_mmap_lock_write(mapping);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
__remove_shared_vm_struct(vma, file, mapping);
mm: use new helper functions around the i_mmap_mutex Convert all open coded mutex_lock/unlock calls to the i_mmap_[lock/unlock]_write() helpers. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:54:21 +03:00
i_mmap_unlock_write(mapping);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
[PATCH] mm: unlink_file_vma, remove_vma Divide remove_vm_struct into two parts: first anon_vma_unlink plus unlink_file_vma, to unlink the vma from the list and tree by which rmap or vmtruncate might find it; then remove_vma to close, fput and free. The intention here is to do the anon_vma_unlink and unlink_file_vma earlier, in free_pgtables before freeing any page tables: so we can be sure that any page tables traversed by rmap and vmtruncate are stable (and other, ordinary cases are stabilized by holding mmap_sem). This will be crucial to traversing pgd,pud,pmd without page_table_lock. But testing the split-out patch showed that lifting the page_table_lock is symbiotically necessary to make this change - the lock ordering is wrong to move those unlinks into free_pgtables while it's under ptlock. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:57 +03:00
}
/*
* Close a vm structure and free it, returning the next.
*/
static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
{
struct vm_area_struct *next = vma->vm_next;
might_sleep();
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
mm: kill vma flag VM_EXECUTABLE and mm->num_exe_file_vmas Currently the kernel sets mm->exe_file during sys_execve() and then tracks number of vmas with VM_EXECUTABLE flag in mm->num_exe_file_vmas, as soon as this counter drops to zero kernel resets mm->exe_file to NULL. Plus it resets mm->exe_file at last mmput() when mm->mm_users drops to zero. VMA with VM_EXECUTABLE flag appears after mapping file with flag MAP_EXECUTABLE, such vmas can appears only at sys_execve() or after vma splitting, because sys_mmap ignores this flag. Usually binfmt module sets mm->exe_file and mmaps executable vmas with this file, they hold mm->exe_file while task is running. comment from v2.6.25-6245-g925d1c4 ("procfs task exe symlink"), where all this stuff was introduced: > The kernel implements readlink of /proc/pid/exe by getting the file from > the first executable VMA. Then the path to the file is reconstructed and > reported as the result. > > Because of the VMA walk the code is slightly different on nommu systems. > This patch avoids separate /proc/pid/exe code on nommu systems. Instead of > walking the VMAs to find the first executable file-backed VMA we store a > reference to the exec'd file in the mm_struct. > > That reference would prevent the filesystem holding the executable file > from being unmounted even after unmapping the VMAs. So we track the number > of VM_EXECUTABLE VMAs and drop the new reference when the last one is > unmapped. This avoids pinning the mounted filesystem. exe_file's vma accounting is hooked into every file mmap/unmmap and vma split/merge just to fix some hypothetical pinning fs from umounting by mm, which already unmapped all its executable files, but still alive. Seems like currently nobody depends on this behaviour. We can try to remove this logic and keep mm->exe_file until final mmput(). mm->exe_file is still protected with mm->mmap_sem, because we want to change it via new sys_prctl(PR_SET_MM_EXE_FILE). Also via this syscall task can change its mm->exe_file and unpin mountpoint explicitly. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Carsten Otte <cotte@de.ibm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Eric Paris <eparis@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Kentaro Takeda <takedakn@nttdata.co.jp> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Venkatesh Pallipadi <venki@google.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:28:54 +04:00
if (vma->vm_file)
[PATCH] mm: unlink_file_vma, remove_vma Divide remove_vm_struct into two parts: first anon_vma_unlink plus unlink_file_vma, to unlink the vma from the list and tree by which rmap or vmtruncate might find it; then remove_vma to close, fput and free. The intention here is to do the anon_vma_unlink and unlink_file_vma earlier, in free_pgtables before freeing any page tables: so we can be sure that any page tables traversed by rmap and vmtruncate are stable (and other, ordinary cases are stabilized by holding mmap_sem). This will be crucial to traversing pgd,pud,pmd without page_table_lock. But testing the split-out patch showed that lifting the page_table_lock is symbiotically necessary to make this change - the lock ordering is wrong to move those unlinks into free_pgtables while it's under ptlock. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:57 +03:00
fput(vma->vm_file);
mempolicy: rename mpol_free to mpol_put This is a change that was requested some time ago by Mel Gorman. Makes sense to me, so here it is. Note: I retain the name "mpol_free_shared_policy()" because it actually does free the shared_policy, which is NOT a reference counted object. However, ... The mempolicy object[s] referenced by the shared_policy are reference counted, so mpol_put() is used to release the reference held by the shared_policy. The mempolicy might not be freed at this time, because some task attached to the shared object associated with the shared policy may be in the process of allocating a page based on the mempolicy. In that case, the task performing the allocation will hold a reference on the mempolicy, obtained via mpol_shared_policy_lookup(). The mempolicy will be freed when all tasks holding such a reference have called mpol_put() for the mempolicy. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 13:13:08 +04:00
mpol_put(vma_policy(vma));
mm: use helper functions for allocating and freeing vm_area structs The vm_area_struct is one of the most fundamental memory management objects, but the management of it is entirely open-coded evertwhere, ranging from allocation and freeing (using kmem_cache_[z]alloc and kmem_cache_free) to initializing all the fields. We want to unify this in order to end up having some unified initialization of the vmas, and the first step to this is to at least have basic allocation functions. Right now those functions are literally just wrappers around the kmem_cache_*() calls. This is a purely mechanical conversion: # new vma: kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc() # copy old vma kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old) # free vma kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma) to the point where the old vma passed in to the vm_area_dup() function isn't even used yet (because I've left all the old manual initialization alone). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-21 23:48:51 +03:00
vm_area_free(vma);
[PATCH] mm: unlink_file_vma, remove_vma Divide remove_vm_struct into two parts: first anon_vma_unlink plus unlink_file_vma, to unlink the vma from the list and tree by which rmap or vmtruncate might find it; then remove_vma to close, fput and free. The intention here is to do the anon_vma_unlink and unlink_file_vma earlier, in free_pgtables before freeing any page tables: so we can be sure that any page tables traversed by rmap and vmtruncate are stable (and other, ordinary cases are stabilized by holding mmap_sem). This will be crucial to traversing pgd,pud,pmd without page_table_lock. But testing the split-out patch showed that lifting the page_table_lock is symbiotically necessary to make this change - the lock ordering is wrong to move those unlinks into free_pgtables while it's under ptlock. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:57 +03:00
return next;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: do not bug_on on incorrect length in __mm_populate() syzbot has noticed that a specially crafted library can easily hit VM_BUG_ON in __mm_populate kernel BUG at mm/gup.c:1242! invalid opcode: 0000 [#1] SMP CPU: 2 PID: 9667 Comm: a.out Not tainted 4.18.0-rc3 #644 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 RIP: 0010:__mm_populate+0x1e2/0x1f0 Code: 55 d0 65 48 33 14 25 28 00 00 00 89 d8 75 21 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 18 f1 ff 0f 0b e8 6e 18 f1 ff <0f> 0b 31 db eb c9 e8 93 06 e0 ff 0f 1f 00 55 48 89 e5 53 48 89 fb Call Trace: vm_brk_flags+0xc3/0x100 vm_brk+0x1f/0x30 load_elf_library+0x281/0x2e0 __ia32_sys_uselib+0x170/0x1e0 do_fast_syscall_32+0xca/0x420 entry_SYSENTER_compat+0x70/0x7f The reason is that the length of the new brk is not page aligned when we try to populate the it. There is no reason to bug on that though. do_brk_flags already aligns the length properly so the mapping is expanded as it should. All we need is to tell mm_populate about it. Besides that there is absolutely no reason to to bug_on in the first place. The worst thing that could happen is that the last page wouldn't get populated and that is far from putting system into an inconsistent state. Fix the issue by moving the length sanitization code from do_brk_flags up to vm_brk_flags. The only other caller of do_brk_flags is brk syscall entry and it makes sure to provide the proper length so t here is no need for sanitation and so we can use do_brk_flags without it. Also remove the bogus BUG_ONs. [osalvador@techadventures.net: fix up vm_brk_flags s@request@len@] Link: http://lkml.kernel.org/r/20180706090217.GI32658@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: syzbot <syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-14 02:59:20 +03:00
static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long flags,
struct list_head *uf);
[CVE-2009-0029] System call wrappers part 13 Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 16:14:15 +03:00
SYSCALL_DEFINE1(brk, unsigned long, brk)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm: use may_adjust_brk helper Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Kees Cook <keescook@chromium.org> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Vasiliy Kulikov <segoon@openwall.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Julien Tinnes <jln@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:27:32 +04:00
unsigned long retval;
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
unsigned long newbrk, oldbrk, origbrk;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
struct mm_struct *mm = current->mm;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
struct vm_area_struct *next;
brk: make sys_brk() honor COMPAT_BRK when computing lower bound Fix a regression introduced by commit 4cc6028d4040f95cdb590a87db478b42b8be0508 Author: Jiri Kosina <jkosina@suse.cz> Date: Wed Feb 6 22:39:44 2008 +0100 brk: check the lower bound properly The check in sys_brk() on minimum value the brk might have must take CONFIG_COMPAT_BRK setting into account. When this option is turned on (i.e. we support ancient legacy binaries, e.g. libc5-linked stuff), the lower bound on brk value is mm->end_code, otherwise the brk start is allowed to be arbitrarily shifted. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-06 09:46:05 +04:00
unsigned long min_brk;
mm: use mm_populate() when adjusting brk with MCL_FUTURE in effect Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:40 +04:00
bool populate;
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
bool downgraded = false;
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
LIST_HEAD(uf);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
if (mmap_write_lock_killable(mm))
mm: make mmap_sem for write waits killable for mm syscalls This is a follow up work for oom_reaper [1]. As the async OOM killing depends on oom_sem for read we would really appreciate if a holder for write didn't stood in the way. This patchset is changing many of down_write calls to be killable to help those cases when the writer is blocked and waiting for readers to release the lock and so help __oom_reap_task to process the oom victim. Most of the patches are really trivial because the lock is help from a shallow syscall paths where we can return EINTR trivially and allow the current task to die (note that EINTR will never get to the userspace as the task has fatal signal pending). Others seem to be easy as well as the callers are already handling fatal errors and bail and return to userspace which should be sufficient to handle the failure gracefully. I am not familiar with all those code paths so a deeper review is really appreciated. As this work is touching more areas which are not directly connected I have tried to keep the CC list as small as possible and people who I believed would be familiar are CCed only to the specific patches (all should have received the cover though). This patchset is based on linux-next and it depends on down_write_killable for rw_semaphores which got merged into tip locking/rwsem branch and it is merged into this next tree. I guess it would be easiest to route these patches via mmotm because of the dependency on the tip tree but if respective maintainers prefer other way I have no objections. I haven't covered all the mmap_write(mm->mmap_sem) instances here $ git grep "down_write(.*\<mmap_sem\>)" next/master | wc -l 98 $ git grep "down_write(.*\<mmap_sem\>)" | wc -l 62 I have tried to cover those which should be relatively easy to review in this series because this alone should be a nice improvement. Other places can be changed on top. [0] http://lkml.kernel.org/r/1456752417-9626-1-git-send-email-mhocko@kernel.org [1] http://lkml.kernel.org/r/1452094975-551-1-git-send-email-mhocko@kernel.org [2] http://lkml.kernel.org/r/1456750705-7141-1-git-send-email-mhocko@kernel.org This patch (of 18): This is the first step in making mmap_sem write waiters killable. It focuses on the trivial ones which are taking the lock early after entering the syscall and they are not changing state before. Therefore it is very easy to change them to use down_write_killable and immediately return with -EINTR. This will allow the waiter to pass away without blocking the mmap_sem which might be required to make a forward progress. E.g. the oom reaper will need the lock for reading to dismantle the OOM victim address space. The only tricky function in this patch is vm_mmap_pgoff which has many call sites via vm_mmap. To reduce the risk keep vm_mmap with the original non-killable semantic for now. vm_munmap callers do not bother checking the return value so open code it into the munmap syscall path for now for simplicity. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-24 02:25:27 +03:00
return -EINTR;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
origbrk = mm->brk;
brk: make sys_brk() honor COMPAT_BRK when computing lower bound Fix a regression introduced by commit 4cc6028d4040f95cdb590a87db478b42b8be0508 Author: Jiri Kosina <jkosina@suse.cz> Date: Wed Feb 6 22:39:44 2008 +0100 brk: check the lower bound properly The check in sys_brk() on minimum value the brk might have must take CONFIG_COMPAT_BRK setting into account. When this option is turned on (i.e. we support ancient legacy binaries, e.g. libc5-linked stuff), the lower bound on brk value is mm->end_code, otherwise the brk start is allowed to be arbitrarily shifted. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-06 09:46:05 +04:00
#ifdef CONFIG_COMPAT_BRK
brk: fix min_brk lower bound computation for COMPAT_BRK Even if CONFIG_COMPAT_BRK is set in the kernel configuration, it can still be overriden by randomize_va_space sysctl. If this is the case, the min_brk computation in sys_brk() implementation is wrong, as it solely takes into account COMPAT_BRK setting, assuming that brk start is not randomized. But that might not be the case if randomize_va_space sysctl has been set to '2' at the time the binary has been loaded from disk. In such case, the check has to be done in a same way as in !CONFIG_COMPAT_BRK case. In addition to that, the check for the COMPAT_BRK case introduced back in a5b4592c ("brk: make sys_brk() honor COMPAT_BRK when computing lower bound") is slightly wrong -- the lower bound shouldn't be mm->end_code, but mm->end_data instead, as that's where the legacy applications expect brk section to start (i.e. immediately after last global variable). [akpm@linux-foundation.org: fix comment] Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-14 02:47:23 +03:00
/*
* CONFIG_COMPAT_BRK can still be overridden by setting
* randomize_va_space to 2, which will still cause mm->start_brk
* to be arbitrarily shifted
*/
brk: COMPAT_BRK: fix detection of randomized brk 5520e89 ("brk: fix min_brk lower bound computation for COMPAT_BRK") tried to get the whole logic of brk randomization for legacy (libc5-based) applications finally right. It turns out that the way to detect whether brk has actually been randomized in the end or not introduced by that patch still doesn't work for those binaries, as reported by Geert: : /sbin/init from my old m68k ramdisk exists prematurely. : : Before the patch: : : | brk(0x80005c8e) = 0x80006000 : : After the patch: : : | brk(0x80005c8e) = 0x80005c8e : : Old libc5 considers brk() to have failed if the return value is not : identical to the requested value. I don't like it, but currently see no better option than a bit flag in task_struct to catch the CONFIG_COMPAT_BRK && randomize_va_space == 2 case. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-15 02:22:09 +04:00
if (current->brk_randomized)
brk: fix min_brk lower bound computation for COMPAT_BRK Even if CONFIG_COMPAT_BRK is set in the kernel configuration, it can still be overriden by randomize_va_space sysctl. If this is the case, the min_brk computation in sys_brk() implementation is wrong, as it solely takes into account COMPAT_BRK setting, assuming that brk start is not randomized. But that might not be the case if randomize_va_space sysctl has been set to '2' at the time the binary has been loaded from disk. In such case, the check has to be done in a same way as in !CONFIG_COMPAT_BRK case. In addition to that, the check for the COMPAT_BRK case introduced back in a5b4592c ("brk: make sys_brk() honor COMPAT_BRK when computing lower bound") is slightly wrong -- the lower bound shouldn't be mm->end_code, but mm->end_data instead, as that's where the legacy applications expect brk section to start (i.e. immediately after last global variable). [akpm@linux-foundation.org: fix comment] Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-14 02:47:23 +03:00
min_brk = mm->start_brk;
else
min_brk = mm->end_data;
brk: make sys_brk() honor COMPAT_BRK when computing lower bound Fix a regression introduced by commit 4cc6028d4040f95cdb590a87db478b42b8be0508 Author: Jiri Kosina <jkosina@suse.cz> Date: Wed Feb 6 22:39:44 2008 +0100 brk: check the lower bound properly The check in sys_brk() on minimum value the brk might have must take CONFIG_COMPAT_BRK setting into account. When this option is turned on (i.e. we support ancient legacy binaries, e.g. libc5-linked stuff), the lower bound on brk value is mm->end_code, otherwise the brk start is allowed to be arbitrarily shifted. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-06 09:46:05 +04:00
#else
min_brk = mm->start_brk;
#endif
if (brk < min_brk)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
goto out;
[PATCH] mm: fix bug in brk() The code checks for newbrk with oldbrk which are page aligned before making a check for the memory limit set of data segment. If the memory limit is not page aligned in that case it bypasses the test for the limit if the memory allocation is still for the same page. Signed-off-by: Ram Gupta <ram.gupta5@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-11 09:52:57 +04:00
/*
* Check against rlimit here. If this check is done later after the test
* of oldbrk with newbrk then it can escape the test and let the data
* segment grow beyond its set limit the in case where the limit is
* not page aligned -Ram Gupta
*/
mm: use may_adjust_brk helper Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Kees Cook <keescook@chromium.org> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Vasiliy Kulikov <segoon@openwall.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Julien Tinnes <jln@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:27:32 +04:00
if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk,
mm->end_data, mm->start_data))
[PATCH] mm: fix bug in brk() The code checks for newbrk with oldbrk which are page aligned before making a check for the memory limit set of data segment. If the memory limit is not page aligned in that case it bypasses the test for the limit if the memory allocation is still for the same page. Signed-off-by: Ram Gupta <ram.gupta5@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-11 09:52:57 +04:00
goto out;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
newbrk = PAGE_ALIGN(brk);
oldbrk = PAGE_ALIGN(mm->brk);
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
if (oldbrk == newbrk) {
mm->brk = brk;
goto success;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
/*
* Always allow shrinking brk.
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* __do_munmap() may downgrade mmap_lock to read.
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
*/
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (brk <= mm->brk) {
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
int ret;
/*
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* mm->brk must to be protected by write mmap_lock so update it
* before downgrading mmap_lock. When __do_munmap() fails,
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
* mm->brk will be restored from origbrk.
*/
mm->brk = brk;
ret = __do_munmap(mm, newbrk, oldbrk-newbrk, &uf, true);
if (ret < 0) {
mm->brk = origbrk;
goto out;
} else if (ret == 1) {
downgraded = true;
}
goto success;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/* Check against existing mmap mappings. */
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
next = find_vma(mm, oldbrk);
if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
goto out;
/* Ok, looks good - let it rip. */
mm: do not bug_on on incorrect length in __mm_populate() syzbot has noticed that a specially crafted library can easily hit VM_BUG_ON in __mm_populate kernel BUG at mm/gup.c:1242! invalid opcode: 0000 [#1] SMP CPU: 2 PID: 9667 Comm: a.out Not tainted 4.18.0-rc3 #644 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 RIP: 0010:__mm_populate+0x1e2/0x1f0 Code: 55 d0 65 48 33 14 25 28 00 00 00 89 d8 75 21 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 18 f1 ff 0f 0b e8 6e 18 f1 ff <0f> 0b 31 db eb c9 e8 93 06 e0 ff 0f 1f 00 55 48 89 e5 53 48 89 fb Call Trace: vm_brk_flags+0xc3/0x100 vm_brk+0x1f/0x30 load_elf_library+0x281/0x2e0 __ia32_sys_uselib+0x170/0x1e0 do_fast_syscall_32+0xca/0x420 entry_SYSENTER_compat+0x70/0x7f The reason is that the length of the new brk is not page aligned when we try to populate the it. There is no reason to bug on that though. do_brk_flags already aligns the length properly so the mapping is expanded as it should. All we need is to tell mm_populate about it. Besides that there is absolutely no reason to to bug_on in the first place. The worst thing that could happen is that the last page wouldn't get populated and that is far from putting system into an inconsistent state. Fix the issue by moving the length sanitization code from do_brk_flags up to vm_brk_flags. The only other caller of do_brk_flags is brk syscall entry and it makes sure to provide the proper length so t here is no need for sanitation and so we can use do_brk_flags without it. Also remove the bogus BUG_ONs. [osalvador@techadventures.net: fix up vm_brk_flags s@request@len@] Link: http://lkml.kernel.org/r/20180706090217.GI32658@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: syzbot <syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-14 02:59:20 +03:00
if (do_brk_flags(oldbrk, newbrk-oldbrk, 0, &uf) < 0)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
goto out;
mm->brk = brk;
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
success:
mm: use mm_populate() when adjusting brk with MCL_FUTURE in effect Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:40 +04:00
populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0;
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
if (downgraded)
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_read_unlock(mm);
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
else
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_write_unlock(mm);
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
userfaultfd_unmap_complete(mm, &uf);
mm: use mm_populate() when adjusting brk with MCL_FUTURE in effect Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:40 +04:00
if (populate)
mm_populate(oldbrk, newbrk - oldbrk);
return brk;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
out:
mm: brk: downgrade mmap_sem to read when shrinking brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:54 +03:00
retval = origbrk;
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_write_unlock(mm);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return retval;
}
augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:46:07 +03:00
static inline unsigned long vma_compute_gap(struct vm_area_struct *vma)
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
{
augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:46:07 +03:00
unsigned long gap, prev_end;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
/*
* Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we
* allow two stack_guard_gaps between them here, and when choosing
* an unmapped area; whereas when expanding we only require one.
* That's a little inconsistent, but keeps the code here simpler.
*/
augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:46:07 +03:00
gap = vm_start_gap(vma);
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
if (vma->vm_prev) {
prev_end = vm_end_gap(vma->vm_prev);
augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:46:07 +03:00
if (gap > prev_end)
gap -= prev_end;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
else
augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:46:07 +03:00
gap = 0;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
}
augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:46:07 +03:00
return gap;
}
#ifdef CONFIG_DEBUG_VM_RB
static unsigned long vma_compute_subtree_gap(struct vm_area_struct *vma)
{
unsigned long max = vma_compute_gap(vma), subtree_gap;
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
if (vma->vm_rb.rb_left) {
subtree_gap = rb_entry(vma->vm_rb.rb_left,
struct vm_area_struct, vm_rb)->rb_subtree_gap;
if (subtree_gap > max)
max = subtree_gap;
}
if (vma->vm_rb.rb_right) {
subtree_gap = rb_entry(vma->vm_rb.rb_right,
struct vm_area_struct, vm_rb)->rb_subtree_gap;
if (subtree_gap > max)
max = subtree_gap;
}
return max;
}
mm: validate_mm browse_rb SMP race condition The mmap_sem for reading in validate_mm called from expand_stack is not enough to prevent the argumented rbtree rb_subtree_gap information to change from under us because expand_stack may be running from other threads concurrently which will hold the mmap_sem for reading too. The argumented rbtree is updated with vma_gap_update under the page_table_lock so use it in browse_rb() too to avoid false positives. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:13 +03:00
static int browse_rb(struct mm_struct *mm)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm: validate_mm browse_rb SMP race condition The mmap_sem for reading in validate_mm called from expand_stack is not enough to prevent the argumented rbtree rb_subtree_gap information to change from under us because expand_stack may be running from other threads concurrently which will hold the mmap_sem for reading too. The argumented rbtree is updated with vma_gap_update under the page_table_lock so use it in browse_rb() too to avoid false positives. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:13 +03:00
struct rb_root *root = &mm->mm_rb;
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
int i = 0, j, bug = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
struct rb_node *nd, *pn = NULL;
unsigned long prev = 0, pend = 0;
for (nd = rb_first(root); nd; nd = rb_next(nd)) {
struct vm_area_struct *vma;
vma = rb_entry(nd, struct vm_area_struct, vm_rb);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
if (vma->vm_start < prev) {
mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks - be consistent in printing the test which failed - one message was actually wrong (a<b != b>a) - don't print second bogus warning if browse_rb() failed Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:19 +04:00
pr_emerg("vm_start %lx < prev %lx\n",
vma->vm_start, prev);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
bug = 1;
}
if (vma->vm_start < pend) {
mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks - be consistent in printing the test which failed - one message was actually wrong (a<b != b>a) - don't print second bogus warning if browse_rb() failed Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:19 +04:00
pr_emerg("vm_start %lx < pend %lx\n",
vma->vm_start, pend);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
bug = 1;
}
if (vma->vm_start > vma->vm_end) {
mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks - be consistent in printing the test which failed - one message was actually wrong (a<b != b>a) - don't print second bogus warning if browse_rb() failed Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:19 +04:00
pr_emerg("vm_start %lx > vm_end %lx\n",
vma->vm_start, vma->vm_end);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
bug = 1;
}
mm: validate_mm browse_rb SMP race condition The mmap_sem for reading in validate_mm called from expand_stack is not enough to prevent the argumented rbtree rb_subtree_gap information to change from under us because expand_stack may be running from other threads concurrently which will hold the mmap_sem for reading too. The argumented rbtree is updated with vma_gap_update under the page_table_lock so use it in browse_rb() too to avoid false positives. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:13 +03:00
spin_lock(&mm->page_table_lock);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
mm/mmap.c: use pr_emerg when printing BUG related information Make sure we actually see the output of validate_mm() and browse_rb() before triggering a BUG(). pr_info isn't shown by default so the reason for the BUG() isn't obvious. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-10 01:50:59 +04:00
pr_emerg("free gap %lx, correct %lx\n",
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
vma->rb_subtree_gap,
vma_compute_subtree_gap(vma));
bug = 1;
}
mm: validate_mm browse_rb SMP race condition The mmap_sem for reading in validate_mm called from expand_stack is not enough to prevent the argumented rbtree rb_subtree_gap information to change from under us because expand_stack may be running from other threads concurrently which will hold the mmap_sem for reading too. The argumented rbtree is updated with vma_gap_update under the page_table_lock so use it in browse_rb() too to avoid false positives. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:13 +03:00
spin_unlock(&mm->page_table_lock);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
i++;
pn = nd;
[PATCH] Bug in MM_RB debugging The code is seemingly trying to make sure that rb_next() brings us to successive increasing vma entries. But the two variables, prev and pend, used to perform these checks, are never advanced. Signed-off-by: David S. Miller <davem@davemloft.net> Cc: Andrea Arcangeli <andrea@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-01 07:13:13 +03:00
prev = vma->vm_start;
pend = vma->vm_end;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
j = 0;
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
for (nd = pn; nd; nd = rb_prev(nd))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
j++;
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
if (i != j) {
mm/mmap.c: use pr_emerg when printing BUG related information Make sure we actually see the output of validate_mm() and browse_rb() before triggering a BUG(). pr_info isn't shown by default so the reason for the BUG() isn't obvious. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-10 01:50:59 +04:00
pr_emerg("backwards %d, forwards %d\n", j, i);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
bug = 1;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
return bug ? -1 : i;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
{
struct rb_node *nd;
for (nd = rb_first(root); nd; nd = rb_next(nd)) {
struct vm_area_struct *vma;
vma = rb_entry(nd, struct vm_area_struct, vm_rb);
mm: use VM_BUG_ON_MM where possible Dump the contents of the relevant struct_mm when we hit the bug condition. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:39 +04:00
VM_BUG_ON_VMA(vma != ignore &&
vma->rb_subtree_gap != vma_compute_subtree_gap(vma),
vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
}
mm/mmap.c: mark function as static Mark function as static in mmap.c because they are not used outside this file. This eliminates the following warning in mm/mmap.c: mm/mmap.c:407:6: warning: no previous prototype for `validate_mm' [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-04 01:48:03 +04:00
static void validate_mm(struct mm_struct *mm)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
int bug = 0;
int i = 0;
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
unsigned long highest_address = 0;
mm: add CONFIG_DEBUG_VM_RB build option Add a CONFIG_DEBUG_VM_RB build option for the previously existing DEBUG_MM_RB code. Now that Andi Kleen modified it to avoid using recursive algorithms, we can expose it a bit more. Also extend this code to validate_mm() after stack expansion, and to check that the vma's start and last pgoffs have not changed since the nodes were inserted on the anon vma interval tree (as it is important that the nodes be reindexed after each such update). Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:45 +04:00
struct vm_area_struct *vma = mm->mmap;
mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks - be consistent in printing the test which failed - one message was actually wrong (a<b != b>a) - don't print second bogus warning if browse_rb() failed Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:19 +04:00
mm: add CONFIG_DEBUG_VM_RB build option Add a CONFIG_DEBUG_VM_RB build option for the previously existing DEBUG_MM_RB code. Now that Andi Kleen modified it to avoid using recursive algorithms, we can expose it a bit more. Also extend this code to validate_mm() after stack expansion, and to check that the vma's start and last pgoffs have not changed since the nodes were inserted on the anon vma interval tree (as it is important that the nodes be reindexed after each such update). Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:45 +04:00
while (vma) {
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
struct anon_vma *anon_vma = vma->anon_vma;
mm: add CONFIG_DEBUG_VM_RB build option Add a CONFIG_DEBUG_VM_RB build option for the previously existing DEBUG_MM_RB code. Now that Andi Kleen modified it to avoid using recursive algorithms, we can expose it a bit more. Also extend this code to validate_mm() after stack expansion, and to check that the vma's start and last pgoffs have not changed since the nodes were inserted on the anon vma interval tree (as it is important that the nodes be reindexed after each such update). Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:45 +04:00
struct anon_vma_chain *avc;
mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks - be consistent in printing the test which failed - one message was actually wrong (a<b != b>a) - don't print second bogus warning if browse_rb() failed Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:19 +04:00
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
if (anon_vma) {
anon_vma_lock_read(anon_vma);
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
anon_vma_interval_tree_verify(avc);
anon_vma_unlock_read(anon_vma);
}
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
highest_address = vm_end_gap(vma);
mm: add CONFIG_DEBUG_VM_RB build option Add a CONFIG_DEBUG_VM_RB build option for the previously existing DEBUG_MM_RB code. Now that Andi Kleen modified it to avoid using recursive algorithms, we can expose it a bit more. Also extend this code to validate_mm() after stack expansion, and to check that the vma's start and last pgoffs have not changed since the nodes were inserted on the anon vma interval tree (as it is important that the nodes be reindexed after each such update). Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:45 +04:00
vma = vma->vm_next;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
i++;
}
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
if (i != mm->map_count) {
mm/mmap.c: use pr_emerg when printing BUG related information Make sure we actually see the output of validate_mm() and browse_rb() before triggering a BUG(). pr_info isn't shown by default so the reason for the BUG() isn't obvious. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-10 01:50:59 +04:00
pr_emerg("map_count %d vm_next %d\n", mm->map_count, i);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
bug = 1;
}
if (highest_address != mm->highest_vm_end) {
mm/mmap.c: use pr_emerg when printing BUG related information Make sure we actually see the output of validate_mm() and browse_rb() before triggering a BUG(). pr_info isn't shown by default so the reason for the BUG() isn't obvious. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-10 01:50:59 +04:00
pr_emerg("mm->highest_vm_end %lx, found %lx\n",
mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks - be consistent in printing the test which failed - one message was actually wrong (a<b != b>a) - don't print second bogus warning if browse_rb() failed Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:19 +04:00
mm->highest_vm_end, highest_address);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
bug = 1;
}
mm: validate_mm browse_rb SMP race condition The mmap_sem for reading in validate_mm called from expand_stack is not enough to prevent the argumented rbtree rb_subtree_gap information to change from under us because expand_stack may be running from other threads concurrently which will hold the mmap_sem for reading too. The argumented rbtree is updated with vma_gap_update under the page_table_lock so use it in browse_rb() too to avoid false positives. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:13 +03:00
i = browse_rb(mm);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
if (i != mm->map_count) {
mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks - be consistent in printing the test which failed - one message was actually wrong (a<b != b>a) - don't print second bogus warning if browse_rb() failed Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:19 +04:00
if (i != -1)
pr_emerg("map_count %d rb %d\n", mm->map_count, i);
mm: check rb_subtree_gap correctness When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly set for every vma and that mm->highest_vm_end is also correct. Also add an explicit 'bug' variable to track if browse_rb() detected any invalid condition. [akpm@linux-foundation.org: repair innovative coding-style inventions] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:42 +04:00
bug = 1;
}
mm: use VM_BUG_ON_MM where possible Dump the contents of the relevant struct_mm when we hit the bug condition. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:39 +04:00
VM_BUG_ON_MM(bug, mm);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
#else
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
#define validate_mm_rb(root, ignore) do { } while (0)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
#define validate_mm(mm) do { } while (0)
#endif
augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:46:07 +03:00
RB_DECLARE_CALLBACKS_MAX(static, vma_gap_callbacks,
struct vm_area_struct, vm_rb,
unsigned long, rb_subtree_gap, vma_compute_gap)
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
/*
* Update augmented rbtree rb_subtree_gap values after vma->vm_start or
* vma->vm_prev->vm_end values changed, without modifying the vma's position
* in the rbtree.
*/
static void vma_gap_update(struct vm_area_struct *vma)
{
/*
augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:46:07 +03:00
* As it turns out, RB_DECLARE_CALLBACKS_MAX() already created
* a callback function that does exactly what we want.
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
*/
vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
}
static inline void vma_rb_insert(struct vm_area_struct *vma,
struct rb_root *root)
{
/* All rb_subtree_gap values must be consistent prior to insertion */
validate_mm_rb(root, NULL);
rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
}
mm: vma_merge: correct false positive from __vma_unlink->validate_mm_rb The old code was always doing: vma->vm_end = next->vm_end vma_rb_erase(next) // in __vma_unlink vma->vm_next = next->vm_next // in __vma_unlink next = vma->vm_next vma_gap_update(next) The new code still does the above for remove_next == 1 and 2, but for remove_next == 3 it has been changed and it does: next->vm_start = vma->vm_start vma_rb_erase(vma) // in __vma_unlink vma_gap_update(next) In the latter case, while unlinking "vma", validate_mm_rb() is told to ignore "vma" that is being removed, but next->vm_start was reduced instead. So for the new case, to avoid the false positive from validate_mm_rb, it should be "next" that is ignored when "vma" is being unlinked. "vma" and "next" in the above comment, considered pre-swap(). Link: http://lkml.kernel.org/r/1474492522-2261-4-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:37 +03:00
static void __vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
{
/*
* Note rb_erase_augmented is a fairly large inline function,
* so make sure we instantiate it only once with our desired
* augmented rbtree callbacks.
*/
rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
}
mm: vma_merge: correct false positive from __vma_unlink->validate_mm_rb The old code was always doing: vma->vm_end = next->vm_end vma_rb_erase(next) // in __vma_unlink vma->vm_next = next->vm_next // in __vma_unlink next = vma->vm_next vma_gap_update(next) The new code still does the above for remove_next == 1 and 2, but for remove_next == 3 it has been changed and it does: next->vm_start = vma->vm_start vma_rb_erase(vma) // in __vma_unlink vma_gap_update(next) In the latter case, while unlinking "vma", validate_mm_rb() is told to ignore "vma" that is being removed, but next->vm_start was reduced instead. So for the new case, to avoid the false positive from validate_mm_rb, it should be "next" that is ignored when "vma" is being unlinked. "vma" and "next" in the above comment, considered pre-swap(). Link: http://lkml.kernel.org/r/1474492522-2261-4-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:37 +03:00
static __always_inline void vma_rb_erase_ignore(struct vm_area_struct *vma,
struct rb_root *root,
struct vm_area_struct *ignore)
{
/*
* All rb_subtree_gap values must be consistent prior to erase,
mm/mmap: leverage vma_rb_erase_ignore() to implement vma_rb_erase() These two functions share the same logic except ignore a different vma. Let's reuse the code. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200809232057.23477-2-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:53:35 +03:00
* with the possible exception of
*
* a. the "next" vma being erased if next->vm_start was reduced in
* __vma_adjust() -> __vma_unlink()
* b. the vma being erased in detach_vmas_to_be_unmapped() ->
* vma_rb_erase()
mm: vma_merge: correct false positive from __vma_unlink->validate_mm_rb The old code was always doing: vma->vm_end = next->vm_end vma_rb_erase(next) // in __vma_unlink vma->vm_next = next->vm_next // in __vma_unlink next = vma->vm_next vma_gap_update(next) The new code still does the above for remove_next == 1 and 2, but for remove_next == 3 it has been changed and it does: next->vm_start = vma->vm_start vma_rb_erase(vma) // in __vma_unlink vma_gap_update(next) In the latter case, while unlinking "vma", validate_mm_rb() is told to ignore "vma" that is being removed, but next->vm_start was reduced instead. So for the new case, to avoid the false positive from validate_mm_rb, it should be "next" that is ignored when "vma" is being unlinked. "vma" and "next" in the above comment, considered pre-swap(). Link: http://lkml.kernel.org/r/1474492522-2261-4-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:37 +03:00
*/
validate_mm_rb(root, ignore);
__vma_rb_erase(vma, root);
}
static __always_inline void vma_rb_erase(struct vm_area_struct *vma,
struct rb_root *root)
{
mm/mmap: leverage vma_rb_erase_ignore() to implement vma_rb_erase() These two functions share the same logic except ignore a different vma. Let's reuse the code. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200809232057.23477-2-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:53:35 +03:00
vma_rb_erase_ignore(vma, root, vma);
mm: vma_merge: correct false positive from __vma_unlink->validate_mm_rb The old code was always doing: vma->vm_end = next->vm_end vma_rb_erase(next) // in __vma_unlink vma->vm_next = next->vm_next // in __vma_unlink next = vma->vm_next vma_gap_update(next) The new code still does the above for remove_next == 1 and 2, but for remove_next == 3 it has been changed and it does: next->vm_start = vma->vm_start vma_rb_erase(vma) // in __vma_unlink vma_gap_update(next) In the latter case, while unlinking "vma", validate_mm_rb() is told to ignore "vma" that is being removed, but next->vm_start was reduced instead. So for the new case, to avoid the false positive from validate_mm_rb, it should be "next" that is ignored when "vma" is being unlinked. "vma" and "next" in the above comment, considered pre-swap(). Link: http://lkml.kernel.org/r/1474492522-2261-4-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:37 +03:00
}
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
/*
* vma has some anon_vma assigned, and is already inserted on that
* anon_vma's interval trees.
*
* Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
* vma must be removed from the anon_vma's interval trees using
* anon_vma_interval_tree_pre_update_vma().
*
* After the update, the vma will be reinserted using
* anon_vma_interval_tree_post_update_vma().
*
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* The entire update must be protected by exclusive mmap_lock and by
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
* the root anon_vma's mutex.
*/
static inline void
anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma)
{
struct anon_vma_chain *avc;
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root);
}
static inline void
anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
{
struct anon_vma_chain *avc;
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
}
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
static int find_vma_links(struct mm_struct *mm, unsigned long addr,
unsigned long end, struct vm_area_struct **pprev,
struct rb_node ***rb_link, struct rb_node **rb_parent)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
struct rb_node **__rb_link, *__rb_parent, *rb_prev;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
__rb_link = &mm->mm_rb.rb_node;
rb_prev = __rb_parent = NULL;
while (*__rb_link) {
struct vm_area_struct *vma_tmp;
__rb_parent = *__rb_link;
vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
if (vma_tmp->vm_end > addr) {
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
/* Fail if an existing vma overlaps the area */
if (vma_tmp->vm_start < end)
return -ENOMEM;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
__rb_link = &__rb_parent->rb_left;
} else {
rb_prev = __rb_parent;
__rb_link = &__rb_parent->rb_right;
}
}
*pprev = NULL;
if (rb_prev)
*pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
*rb_link = __rb_link;
*rb_parent = __rb_parent;
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
return 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm/mmap: add inline vma_next() for readability of mmap code There are three places that the next vma is required which uses the same block of code. Replace the block with a function and add comments on what happens in the case where NULL is encountered. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200818154707.2515169-1-Liam.Howlett@Oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 02:14:06 +03:00
/*
* vma_next() - Get the next VMA.
* @mm: The mm_struct.
* @vma: The current vma.
*
* If @vma is NULL, return the first vma in the mm.
*
* Returns: The next VMA after @vma.
*/
static inline struct vm_area_struct *vma_next(struct mm_struct *mm,
struct vm_area_struct *vma)
{
if (!vma)
return mm->mmap;
return vma->vm_next;
}
mm/mmap: add inline munmap_vma_range() for code readability There are two locations that have a block of code for munmapping a vma range. Change those two locations to use a function and add meaningful comments about what happens to the arguments, which was unclear in the previous code. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200818154707.2515169-2-Liam.Howlett@Oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 02:14:09 +03:00
/*
* munmap_vma_range() - munmap VMAs that overlap a range.
* @mm: The mm struct
* @start: The start of the range.
* @len: The length of the range.
* @pprev: pointer to the pointer that will be set to previous vm_area_struct
* @rb_link: the rb_node
* @rb_parent: the parent rb_node
*
* Find all the vm_area_struct that overlap from @start to
* @end and munmap them. Set @pprev to the previous vm_area_struct.
*
* Returns: -ENOMEM on munmap failure or 0 on success.
*/
static inline int
munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
struct vm_area_struct **pprev, struct rb_node ***link,
struct rb_node **parent, struct list_head *uf)
{
while (find_vma_links(mm, start, start + len, pprev, link, parent))
if (do_munmap(mm, start, len, uf))
return -ENOMEM;
return 0;
}
mm/mmap: check for RLIMIT_AS before unmapping Fix a corner case for MAP_FIXED when requested mapping length is larger than rlimit for virtual memory. In such case any overlapping mappings are unmapped before we check for the limit and return ENOMEM. The check is moved before the loop that unmaps overlapping parts of existing mappings. When we are about to hit the limit (currently mapped pages + len > limit) we scan for overlapping pages and check again accounting for them. This fixes situation when userspace program expects that the previous mappings are preserved after the mmap() syscall has returned with error. (POSIX clearly states that successfull mapping shall replace any previous mappings.) This corner case was found and can be tested with LTP testcase: testcases/open_posix_testsuite/conformance/interfaces/mmap/24-2.c In this case the mmap, which is clearly over current limit, unmaps dynamic libraries and the testcase segfaults right after returning into userspace. I've also looked at the second instance of the unmapping loop in the do_brk(). The do_brk() is called from brk() syscall and from vm_brk(). The brk() syscall checks for overlapping mappings and bails out when there are any (so it can't be triggered from the brk syscall). The vm_brk() is called only from binmft handlers so it shouldn't be triggered unless binmft handler created overlapping mappings. Signed-off-by: Cyril Hrubis <chrubis@suse.cz> Reviewed-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:33 +04:00
static unsigned long count_vma_pages_range(struct mm_struct *mm,
unsigned long addr, unsigned long end)
{
unsigned long nr_pages = 0;
struct vm_area_struct *vma;
/* Find first overlaping mapping */
vma = find_vma_intersection(mm, addr, end);
if (!vma)
return 0;
nr_pages = (min(end, vma->vm_end) -
max(addr, vma->vm_start)) >> PAGE_SHIFT;
/* Iterate over the rest of the overlaps */
for (vma = vma->vm_next; vma; vma = vma->vm_next) {
unsigned long overlap_len;
if (vma->vm_start > end)
break;
overlap_len = min(end, vma->vm_end) - vma->vm_start;
nr_pages += overlap_len >> PAGE_SHIFT;
}
return nr_pages;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
struct rb_node **rb_link, struct rb_node *rb_parent)
{
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
/* Update tracking information for the gap following the new vma. */
if (vma->vm_next)
vma_gap_update(vma->vm_next);
else
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
mm->highest_vm_end = vm_end_gap(vma);
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
/*
* vma->vm_prev wasn't known when we followed the rbtree to find the
* correct insertion point for that vma. As a result, we could not
* update the vma vm_rb parents rb_subtree_gap values on the way down.
* So, we first insert the vma with a zero rb_subtree_gap value
* (to be consistent with what we did on the way down), and then
* immediately update the gap to the correct value. Finally we
* rebalance the rbtree after all augmented values have been set.
*/
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
rb_link_node(&vma->vm_rb, rb_parent, rb_link);
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
vma->rb_subtree_gap = 0;
vma_gap_update(vma);
vma_rb_insert(vma, &mm->mm_rb);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mmap.c: deinline a few functions __vma_link_file and expand_downwards functions are not small, yeat they are marked inline. They probably had one callsite sometime in the past, but now they have more. In order to prevent similar thing, I also deinlined expand_upwards, despite it having only pne callsite. Nowadays gcc auto-inlines such static functions anyway. In find_extend_vma, I removed one extra level of indirection. Patch is deliberately generated with -U $BIGNUM to make it easier to see that functions are big. Result: # size */*/mmap.o */vmlinux text data bss dec hex filename 9514 188 16 9718 25f6 0.org/mm/mmap.o 9237 188 16 9441 24e1 deinline/mm/mmap.o 6124402 858996 389480 7372878 70804e 0.org/vmlinux 6124113 858996 389480 7372589 707f2d deinline/vmlinux Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:27:01 +04:00
static void __vma_link_file(struct vm_area_struct *vma)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm/mmap.c: fix coding style Fix a little of the coding style in mm/mmap.c [akpm@linux-foundation.org: cleanup] Signed-off-by: ZhenwenXu <helight.xu@gmail.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-07 01:40:21 +03:00
struct file *file;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
file = vma->vm_file;
if (file) {
struct address_space *mapping = file->f_mapping;
if (vma->vm_flags & VM_DENYWRITE)
mm: use helper function put_write_access() In commit 1da177e4c3f4 ("Linux-2.6.12-rc2"), the helper put_write_access() came with the atomic_dec operation of the i_writecount field. But it forgot to use this helper in __vma_link_file() and dup_mmap(). Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200924115235.5111-1-linmiaohe@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 06:10:08 +03:00
put_write_access(file_inode(file));
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (vma->vm_flags & VM_SHARED)
mm: use helper function mapping_allow_writable() Commit 4bb5f5d9395b ("mm: allow drivers to prevent new writable mappings") changed i_mmap_writable from unsigned int to atomic_t and add the helper function mapping_allow_writable() to atomic_inc i_mmap_writable. But it forgot to use this helper function in dup_mmap() and __vma_link_file(). Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Christian Kellner <christian@kellner.me> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Adrian Reber <areber@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200917112736.7789-1-linmiaohe@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:54:10 +03:00
mapping_allow_writable(mapping);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
flush_dcache_mmap_lock(mapping);
rmap: drop support of non-linear mappings We don't create non-linear mappings anymore. Let's drop code which handles them in rmap. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:59 +03:00
vma_interval_tree_insert(vma, &mapping->i_mmap);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
flush_dcache_mmap_unlock(mapping);
}
}
static void
__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, struct rb_node **rb_link,
struct rb_node *rb_parent)
{
mm/mmap.c: rb_parent is not necessary in __vma_link_list() Now we use rb_parent to get next, while this is not necessary. When prev is NULL, this means vma should be the first element in the list. Then next should be current first one (mm->mmap), no matter whether we have parent or not. After removing it, the code shows the beauty of symmetry. Link: http://lkml.kernel.org/r/20190813032656.16625-1-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 04:50:53 +03:00
__vma_link_list(mm, vma, prev);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
__vma_link_rb(mm, vma, rb_link, rb_parent);
}
static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, struct rb_node **rb_link,
struct rb_node *rb_parent)
{
struct address_space *mapping = NULL;
mm/mmap.c: remove the first mapping check Remove the first mapping check for vma_link. Move the mutex_lock into the braces when vma->vm_file is true. Signed-off-by: Huang Shijie <b32955@freescale.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-05 03:07:33 +04:00
if (vma->vm_file) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mapping = vma->vm_file->f_mapping;
mm: use new helper functions around the i_mmap_mutex Convert all open coded mutex_lock/unlock calls to the i_mmap_[lock/unlock]_write() helpers. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:54:21 +03:00
i_mmap_lock_write(mapping);
mm/mmap.c: remove the first mapping check Remove the first mapping check for vma_link. Move the mutex_lock into the braces when vma->vm_file is true. Signed-off-by: Huang Shijie <b32955@freescale.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-05 03:07:33 +04:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
__vma_link(mm, vma, prev, rb_link, rb_parent);
__vma_link_file(vma);
if (mapping)
mm: use new helper functions around the i_mmap_mutex Convert all open coded mutex_lock/unlock calls to the i_mmap_[lock/unlock]_write() helpers. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:54:21 +03:00
i_mmap_unlock_write(mapping);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm->map_count++;
validate_mm(mm);
}
/*
mmap.c: fix comment for __insert_vm_struct() The comment above __insert_vm_struct seems to suggest that this function is also going to link the VMA with the anon_vma, but this is not true. This function only links the VMA to the mm->mm_rb tree and the mm->mmap linked list. [akpm@linux-foundation.org: improve comment layout and text] Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-22 03:34:16 +04:00
* Helper for vma_adjust() in the split_vma insert case: insert a vma into the
mm: replace vma prio_tree with an interval tree Implement an interval tree as a replacement for the VMA prio_tree. The algorithms are similar to lib/interval_tree.c; however that code can't be directly reused as the interval endpoints are not explicitly stored in the VMA. So instead, the common algorithm is moved into a template and the details (node type, how to get interval endpoints from the node, etc) are filled in using the C preprocessor. Once the interval tree functions are available, using them as a replacement to the VMA prio tree is a relatively simple, mechanical job. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:25 +04:00
* mm's list and rbtree. It has already been inserted into the interval tree.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
mm/mmap.c: fix coding style Fix a little of the coding style in mm/mmap.c [akpm@linux-foundation.org: cleanup] Signed-off-by: ZhenwenXu <helight.xu@gmail.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-07 01:40:21 +03:00
static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
struct vm_area_struct *prev;
mm/mmap.c: fix coding style Fix a little of the coding style in mm/mmap.c [akpm@linux-foundation.org: cleanup] Signed-off-by: ZhenwenXu <helight.xu@gmail.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-07 01:40:21 +03:00
struct rb_node **rb_link, *rb_parent;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
if (find_vma_links(mm, vma->vm_start, vma->vm_end,
&prev, &rb_link, &rb_parent))
BUG();
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
__vma_link(mm, vma, prev, rb_link, rb_parent);
mm->map_count++;
}
mm/mmap: rename __vma_unlink_common() to __vma_unlink() __vma_unlink_common() and __vma_unlink() are counterparts. Since there is no function named __vma_unlink(), let's rename __vma_unlink_common() to __vma_unlink() to make the code more self-explanatory and easy for audience to understand. Otherwise we may expect there are several variants of vma_unlink() and __vma_unlink_common() is used by them. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200809232057.23477-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:53:32 +03:00
static __always_inline void __vma_unlink(struct mm_struct *mm,
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
struct vm_area_struct *vma,
mm: vma_merge: correct false positive from __vma_unlink->validate_mm_rb The old code was always doing: vma->vm_end = next->vm_end vma_rb_erase(next) // in __vma_unlink vma->vm_next = next->vm_next // in __vma_unlink next = vma->vm_next vma_gap_update(next) The new code still does the above for remove_next == 1 and 2, but for remove_next == 3 it has been changed and it does: next->vm_start = vma->vm_start vma_rb_erase(vma) // in __vma_unlink vma_gap_update(next) In the latter case, while unlinking "vma", validate_mm_rb() is told to ignore "vma" that is being removed, but next->vm_start was reduced instead. So for the new case, to avoid the false positive from validate_mm_rb, it should be "next" that is ignored when "vma" is being unlinked. "vma" and "next" in the above comment, considered pre-swap(). Link: http://lkml.kernel.org/r/1474492522-2261-4-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:37 +03:00
struct vm_area_struct *ignore)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm: vma_merge: correct false positive from __vma_unlink->validate_mm_rb The old code was always doing: vma->vm_end = next->vm_end vma_rb_erase(next) // in __vma_unlink vma->vm_next = next->vm_next // in __vma_unlink next = vma->vm_next vma_gap_update(next) The new code still does the above for remove_next == 1 and 2, but for remove_next == 3 it has been changed and it does: next->vm_start = vma->vm_start vma_rb_erase(vma) // in __vma_unlink vma_gap_update(next) In the latter case, while unlinking "vma", validate_mm_rb() is told to ignore "vma" that is being removed, but next->vm_start was reduced instead. So for the new case, to avoid the false positive from validate_mm_rb, it should be "next" that is ignored when "vma" is being unlinked. "vma" and "next" in the above comment, considered pre-swap(). Link: http://lkml.kernel.org/r/1474492522-2261-4-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:37 +03:00
vma_rb_erase_ignore(vma, &mm->mm_rb, ignore);
mm/mmap.c: extract __vma_unlink_list() as counterpart for __vma_link_list() Just make the code a little easier to read. Link: http://lkml.kernel.org/r/20191006012636.31521-3-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Oscar Salvador <osalvador@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 04:50:49 +03:00
__vma_unlink_list(mm, vma);
mm: per-thread vma caching This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 02:37:25 +04:00
/* Kill the cache */
vmacache_invalidate(mm);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/*
* We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
* is already present in an i_mmap tree without adjusting the tree.
* The following helper function should be used when such adjustments
* are necessary. The "insert" vma (if any) is to be inserted
* before we drop the necessary locks.
*/
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert,
struct vm_area_struct *expand)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
struct mm_struct *mm = vma->vm_mm;
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
struct vm_area_struct *next = vma->vm_next, *orig_vma = vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
struct address_space *mapping = NULL;
lib/interval_tree: fast overlap detection Allow interval trees to quickly check for overlaps to avoid unnecesary tree lookups in interval_tree_iter_first(). As of this patch, all interval tree flavors will require using a 'rb_root_cached' such that we can have the leftmost node easily available. While most users will make use of this feature, those with special functions (in addition to the generic insert, delete, search calls) will avoid using the cached option as they can do funky things with insertions -- for example, vma_interval_tree_insert_after(). [jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()] Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Jason Wang <jasowang@redhat.com> Cc: Christian Benvenuti <benve@cisco.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-09 02:15:08 +03:00
struct rb_root_cached *root = NULL;
mm: always lock the root (oldest) anon_vma Always (and only) lock the root (oldest) anon_vma whenever we do something in an anon_vma. The recently introduced anon_vma scalability is due to the rmap code scanning only the VMAs that need to be scanned. Many common operations still took the anon_vma lock on the root anon_vma, so always taking that lock is not expected to introduce any scalability issues. However, always taking the same lock does mean we only need to take one lock, which means rmap_walk on pages from any anon_vma in the vma is excluded from occurring during an munmap, expand_stack or other operation that needs to exclude rmap_walk and similar functions. Also add the proper locking to vma_adjust. Signed-off-by: Rik van Riel <riel@redhat.com> Tested-by: Larry Woodman <lwoodman@redhat.com> Acked-by: Larry Woodman <lwoodman@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-10 04:18:40 +04:00
struct anon_vma *anon_vma = NULL;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
struct file *file = vma->vm_file;
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
bool start_changed = false, end_changed = false;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
long adjust_next = 0;
int remove_next = 0;
if (next && !insert) {
mm: fix use-after-free if memory allocation failed in vma_adjust() There's one case when vma_adjust() expands the vma, overlapping with *two* next vma. See case 6 of mprotect, described in the comment to vma_merge(). To handle this (and only this) situation we iterate twice over main part of the function. See "goto again". Vegard reported[1] that he sees out-of-bounds access complain from KASAN, if anon_vma_clone() on the *second* iteration fails. This happens because we free 'next' vma by the end of first iteration and don't have a way to undo this if anon_vma_clone() fails on the second iteration. The solution is to do all required allocations upfront, before we touch vmas. The allocation on the second iteration is only required if first two vmas don't have anon_vma, but third does. So we need, in total, one anon_vma_clone() call. It's easy to adjust 'exporter' to the third vma for such case. [1] http://lkml.kernel.org/r/1469514843-23778-1-git-send-email-vegard.nossum@oracle.com Link: http://lkml.kernel.org/r/1469625255-126641-1-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29 01:49:01 +03:00
struct vm_area_struct *exporter = NULL, *importer = NULL;
vma_adjust: fix the copying of anon_vma chains When we move the boundaries between two vma's due to things like mprotect, we need to make sure that the anon_vma of the pages that got moved from one vma to another gets properly copied around. And that was not always the case, in this rather hard-to-follow code sequence. Clarify the code, and fix it so that it copies the anon_vma from the right source. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "Yeah, not so much this one either" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-11 02:22:30 +04:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (end >= next->vm_end) {
/*
* vma expands, overlapping all the next, and
* perhaps the one after too (mprotect case 6).
mm: vma_adjust: minor comment correction The cases are three not two. Link: http://lkml.kernel.org/r/1474492522-2261-3-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:34 +03:00
* The only other cases that gets here are
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
* case 1, case 7 and case 8.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
if (next == expand) {
/*
* The only case where we don't expand "vma"
* and we expand "next" instead is case 8.
*/
VM_WARN_ON(end != next->vm_end);
/*
* remove_next == 3 means we're
* removing "vma" and that to do so we
* swapped "vma" and "next".
*/
remove_next = 3;
VM_WARN_ON(file != next->vm_file);
swap(vma, next);
} else {
VM_WARN_ON(expand != vma);
/*
* case 1, 6, 7, remove_next == 2 is case 6,
* remove_next == 1 is case 1 or 7.
*/
remove_next = 1 + (end > next->vm_end);
VM_WARN_ON(remove_next == 2 &&
end != next->vm_next->vm_end);
/* trim end to next, for case 6 first pass */
end = next->vm_end;
}
vma_adjust: fix the copying of anon_vma chains When we move the boundaries between two vma's due to things like mprotect, we need to make sure that the anon_vma of the pages that got moved from one vma to another gets properly copied around. And that was not always the case, in this rather hard-to-follow code sequence. Clarify the code, and fix it so that it copies the anon_vma from the right source. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "Yeah, not so much this one either" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-11 02:22:30 +04:00
exporter = next;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
importer = vma;
mm: fix use-after-free if memory allocation failed in vma_adjust() There's one case when vma_adjust() expands the vma, overlapping with *two* next vma. See case 6 of mprotect, described in the comment to vma_merge(). To handle this (and only this) situation we iterate twice over main part of the function. See "goto again". Vegard reported[1] that he sees out-of-bounds access complain from KASAN, if anon_vma_clone() on the *second* iteration fails. This happens because we free 'next' vma by the end of first iteration and don't have a way to undo this if anon_vma_clone() fails on the second iteration. The solution is to do all required allocations upfront, before we touch vmas. The allocation on the second iteration is only required if first two vmas don't have anon_vma, but third does. So we need, in total, one anon_vma_clone() call. It's easy to adjust 'exporter' to the third vma for such case. [1] http://lkml.kernel.org/r/1469514843-23778-1-git-send-email-vegard.nossum@oracle.com Link: http://lkml.kernel.org/r/1469625255-126641-1-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29 01:49:01 +03:00
/*
* If next doesn't have anon_vma, import from vma after
* next, if the vma overlaps with it.
*/
mm: vma_adjust: remove superfluous check for next not NULL If next would be NULL we couldn't reach such code path. Link: http://lkml.kernel.org/r/1474309513-20313-2-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:31 +03:00
if (remove_next == 2 && !next->anon_vma)
mm: fix use-after-free if memory allocation failed in vma_adjust() There's one case when vma_adjust() expands the vma, overlapping with *two* next vma. See case 6 of mprotect, described in the comment to vma_merge(). To handle this (and only this) situation we iterate twice over main part of the function. See "goto again". Vegard reported[1] that he sees out-of-bounds access complain from KASAN, if anon_vma_clone() on the *second* iteration fails. This happens because we free 'next' vma by the end of first iteration and don't have a way to undo this if anon_vma_clone() fails on the second iteration. The solution is to do all required allocations upfront, before we touch vmas. The allocation on the second iteration is only required if first two vmas don't have anon_vma, but third does. So we need, in total, one anon_vma_clone() call. It's easy to adjust 'exporter' to the third vma for such case. [1] http://lkml.kernel.org/r/1469514843-23778-1-git-send-email-vegard.nossum@oracle.com Link: http://lkml.kernel.org/r/1469625255-126641-1-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29 01:49:01 +03:00
exporter = next->vm_next;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
} else if (end > next->vm_start) {
/*
* vma expands, overlapping part of the next:
* mprotect case 5 shifting the boundary up.
*/
mm/mmap: leave adjust_next as virtual address instead of page frame number Instead of converting adjust_next between bytes and pages number, let's just store the virtual address into adjust_next. Also, this patch fixes one typo in the comment of vma_adjust_trans_huge(). [vbabka@suse.cz: changelog tweak] Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mike Kravetz <mike.kravetz@oracle.com> Link: http://lkml.kernel.org/r/20200828081031.11306-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:53:57 +03:00
adjust_next = (end - next->vm_start);
vma_adjust: fix the copying of anon_vma chains When we move the boundaries between two vma's due to things like mprotect, we need to make sure that the anon_vma of the pages that got moved from one vma to another gets properly copied around. And that was not always the case, in this rather hard-to-follow code sequence. Clarify the code, and fix it so that it copies the anon_vma from the right source. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "Yeah, not so much this one either" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-11 02:22:30 +04:00
exporter = next;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
importer = vma;
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
VM_WARN_ON(expand != importer);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
} else if (end < vma->vm_end) {
/*
* vma shrinks, and !insert tells it's not
* split_vma inserting another: so it must be
* mprotect case 4 shifting the boundary down.
*/
mm/mmap: leave adjust_next as virtual address instead of page frame number Instead of converting adjust_next between bytes and pages number, let's just store the virtual address into adjust_next. Also, this patch fixes one typo in the comment of vma_adjust_trans_huge(). [vbabka@suse.cz: changelog tweak] Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mike Kravetz <mike.kravetz@oracle.com> Link: http://lkml.kernel.org/r/20200828081031.11306-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:53:57 +03:00
adjust_next = -(vma->vm_end - end);
vma_adjust: fix the copying of anon_vma chains When we move the boundaries between two vma's due to things like mprotect, we need to make sure that the anon_vma of the pages that got moved from one vma to another gets properly copied around. And that was not always the case, in this rather hard-to-follow code sequence. Clarify the code, and fix it so that it copies the anon_vma from the right source. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "Yeah, not so much this one either" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-11 02:22:30 +04:00
exporter = vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
importer = next;
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
VM_WARN_ON(expand != importer);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
/*
* Easily overlooked: when mprotect shifts the boundary,
* make sure the expanding vma has anon_vma set if the
* shrinking vma had, to cover any anon pages imported.
*/
vma_adjust: fix the copying of anon_vma chains When we move the boundaries between two vma's due to things like mprotect, we need to make sure that the anon_vma of the pages that got moved from one vma to another gets properly copied around. And that was not always the case, in this rather hard-to-follow code sequence. Clarify the code, and fix it so that it copies the anon_vma from the right source. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "Yeah, not so much this one either" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-11 02:22:30 +04:00
if (exporter && exporter->anon_vma && !importer->anon_vma) {
mm: fix anon_vma_clone() error treatment Andrew Morton noticed that the error return from anon_vma_clone() was being dropped and replaced with -ENOMEM (which is not itself a bug because the only error return value from anon_vma_clone() is -ENOMEM). I did an audit of callers of anon_vma_clone() and discovered an actual bug where the error return was being lost. In __split_vma(), between Linux 3.11 and 3.12 the code was changed so the err variable is used before the call to anon_vma_clone() and the default initial value of -ENOMEM is overwritten. So a failure of anon_vma_clone() will return success since err at this point is now zero. Below is a patch which fixes this bug and also propagates the error return value from anon_vma_clone() in all cases. Fixes: ef0855d334e1 ("mm: mempolicy: turn vma_set_policy() into vma_dup_policy()") Signed-off-by: Daniel Forrest <dan.forrest@ssec.wisc.edu> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Tim Hartrick <tim@edgecast.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-03 02:59:42 +03:00
int error;
mm: fix corner case in anon_vma endless growing prevention Fix for BUG_ON(anon_vma->degree) splashes in unlink_anon_vmas() ("kernel BUG at mm/rmap.c:399!") caused by commit 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy") Anon_vma_clone() is usually called for a copy of source vma in destination argument. If source vma has anon_vma it should be already in dst->anon_vma. NULL in dst->anon_vma is used as a sign that it's called from anon_vma_fork(). In this case anon_vma_clone() finds anon_vma for reusing. Vma_adjust() calls it differently and this breaks anon_vma reusing logic: anon_vma_clone() links vma to old anon_vma and updates degree counters but vma_adjust() overrides vma->anon_vma right after that. As a result final unlink_anon_vmas() decrements degree for wrong anon_vma. This patch assigns ->anon_vma before calling anon_vma_clone(). Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-and-tested-by: Chris Clayton <chris2553@googlemail.com> Reported-and-tested-by: Oded Gabbay <oded.gabbay@amd.com> Reported-and-tested-by: Chih-Wei Huang <cwhuang@android-x86.org> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Daniel Forrest <dan.forrest@ssec.wisc.edu> Cc: Michal Hocko <mhocko@suse.cz> Cc: stable@vger.kernel.org # to match back-porting of 7a3ef208e662 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-01-11 16:54:06 +03:00
importer->anon_vma = exporter->anon_vma;
mm: fix anon_vma_clone() error treatment Andrew Morton noticed that the error return from anon_vma_clone() was being dropped and replaced with -ENOMEM (which is not itself a bug because the only error return value from anon_vma_clone() is -ENOMEM). I did an audit of callers of anon_vma_clone() and discovered an actual bug where the error return was being lost. In __split_vma(), between Linux 3.11 and 3.12 the code was changed so the err variable is used before the call to anon_vma_clone() and the default initial value of -ENOMEM is overwritten. So a failure of anon_vma_clone() will return success since err at this point is now zero. Below is a patch which fixes this bug and also propagates the error return value from anon_vma_clone() in all cases. Fixes: ef0855d334e1 ("mm: mempolicy: turn vma_set_policy() into vma_dup_policy()") Signed-off-by: Daniel Forrest <dan.forrest@ssec.wisc.edu> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Tim Hartrick <tim@edgecast.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-03 02:59:42 +03:00
error = anon_vma_clone(importer, exporter);
mm: fix anon_vma->degree underflow in anon_vma endless growing prevention I have constantly stumbled upon "kernel BUG at mm/rmap.c:399!" after upgrading to 3.19 and had no luck with 4.0-rc1 neither. So, after looking into new logic introduced by commit 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy"), I found chances are that unlink_anon_vmas() is called without incrementing dst->anon_vma->degree in anon_vma_clone() due to allocation failure. If dst->anon_vma is not NULL in error path, its degree will be incorrectly decremented in unlink_anon_vmas() and eventually underflow when exiting as a result of another call to unlink_anon_vmas(). That's how "kernel BUG at mm/rmap.c:399!" is triggered for me. This patch fixes the underflow by dropping dst->anon_vma when allocation fails. It's safe to do so regardless of original value of dst->anon_vma because dst->anon_vma doesn't have valid meaning if anon_vma_clone() fails. Besides, callers don't care dst->anon_vma in such case neither. Also suggested by Michal Hocko, we can clean up vma_adjust() a bit as anon_vma_clone() now does the work. [akpm@linux-foundation.org: tweak comment] Fixes: 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy") Signed-off-by: Leon Yu <chianglungyu@gmail.com> Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-03-26 01:55:11 +03:00
if (error)
mm: fix anon_vma_clone() error treatment Andrew Morton noticed that the error return from anon_vma_clone() was being dropped and replaced with -ENOMEM (which is not itself a bug because the only error return value from anon_vma_clone() is -ENOMEM). I did an audit of callers of anon_vma_clone() and discovered an actual bug where the error return was being lost. In __split_vma(), between Linux 3.11 and 3.12 the code was changed so the err variable is used before the call to anon_vma_clone() and the default initial value of -ENOMEM is overwritten. So a failure of anon_vma_clone() will return success since err at this point is now zero. Below is a patch which fixes this bug and also propagates the error return value from anon_vma_clone() in all cases. Fixes: ef0855d334e1 ("mm: mempolicy: turn vma_set_policy() into vma_dup_policy()") Signed-off-by: Daniel Forrest <dan.forrest@ssec.wisc.edu> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Tim Hartrick <tim@edgecast.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-03 02:59:42 +03:00
return error;
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
}
}
mm: fix use-after-free if memory allocation failed in vma_adjust() There's one case when vma_adjust() expands the vma, overlapping with *two* next vma. See case 6 of mprotect, described in the comment to vma_merge(). To handle this (and only this) situation we iterate twice over main part of the function. See "goto again". Vegard reported[1] that he sees out-of-bounds access complain from KASAN, if anon_vma_clone() on the *second* iteration fails. This happens because we free 'next' vma by the end of first iteration and don't have a way to undo this if anon_vma_clone() fails on the second iteration. The solution is to do all required allocations upfront, before we touch vmas. The allocation on the second iteration is only required if first two vmas don't have anon_vma, but third does. So we need, in total, one anon_vma_clone() call. It's easy to adjust 'exporter' to the third vma for such case. [1] http://lkml.kernel.org/r/1469514843-23778-1-git-send-email-vegard.nossum@oracle.com Link: http://lkml.kernel.org/r/1469625255-126641-1-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29 01:49:01 +03:00
again:
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
vma_adjust_trans_huge(orig_vma, start, end, adjust_next);
thp: run vma_adjust_trans_huge() outside i_mmap_rwsem vma_addjust_trans_huge() splits pmd if it's crossing VMA boundary. During split we munlock the huge page which requires rmap walk. rmap wants to take the lock on its own. Let's move vma_adjust_trans_huge() outside i_mmap_rwsem to fix this. Link: http://lkml.kernel.org/r/1466021202-61880-19-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27 01:25:48 +03:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (file) {
mapping = file->f_mapping;
rmap: drop support of non-linear mappings We don't create non-linear mappings anymore. Let's drop code which handles them in rmap. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:59 +03:00
root = &mapping->i_mmap;
uprobe_munmap(vma, vma->vm_start, vma->vm_end);
uprobes/core: Optimize probe hits with the help of a counter Maintain a per-mm counter: number of uprobes that are inserted on this process address space. This counter can be used at probe hit time to determine if we need a lookup in the uprobes rbtree. Everytime a probe gets inserted successfully, the probe count is incremented and everytime a probe gets removed, the probe count is decremented. The new uprobe_munmap hook ensures the count is correct on a unmap or remap of a region. We expect that once a uprobe_munmap() is called, the vma goes away. So uprobe_unregister() finding a probe to unregister would either mean unmap event hasnt occurred yet or a mmap event on the same executable file occured after a unmap event. Additionally, uprobe_mmap hook now also gets called: a. on every executable vma that is COWed at fork. b. a vma of interest is newly mapped; breakpoint insertion also happens at the required address. On process creation, make sure the probes count in the child is set correctly. Special cases that are taken care include: a. mremap b. VM_DONTCOPY vmas on fork() c. insertion/removal races in the parent during fork(). Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com> Cc: Linux-mm <linux-mm@kvack.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Anton Arapov <anton@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20120330182646.10018.85805.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-30 22:26:46 +04:00
rmap: drop support of non-linear mappings We don't create non-linear mappings anymore. Let's drop code which handles them in rmap. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:59 +03:00
if (adjust_next)
uprobe_munmap(next, next->vm_start, next->vm_end);
uprobes/core: Optimize probe hits with the help of a counter Maintain a per-mm counter: number of uprobes that are inserted on this process address space. This counter can be used at probe hit time to determine if we need a lookup in the uprobes rbtree. Everytime a probe gets inserted successfully, the probe count is incremented and everytime a probe gets removed, the probe count is decremented. The new uprobe_munmap hook ensures the count is correct on a unmap or remap of a region. We expect that once a uprobe_munmap() is called, the vma goes away. So uprobe_unregister() finding a probe to unregister would either mean unmap event hasnt occurred yet or a mmap event on the same executable file occured after a unmap event. Additionally, uprobe_mmap hook now also gets called: a. on every executable vma that is COWed at fork. b. a vma of interest is newly mapped; breakpoint insertion also happens at the required address. On process creation, make sure the probes count in the child is set correctly. Special cases that are taken care include: a. mremap b. VM_DONTCOPY vmas on fork() c. insertion/removal races in the parent during fork(). Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com> Cc: Linux-mm <linux-mm@kvack.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Anton Arapov <anton@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20120330182646.10018.85805.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-30 22:26:46 +04:00
mm: use new helper functions around the i_mmap_mutex Convert all open coded mutex_lock/unlock calls to the i_mmap_[lock/unlock]_write() helpers. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:54:21 +03:00
i_mmap_lock_write(mapping);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (insert) {
/*
mm: replace vma prio_tree with an interval tree Implement an interval tree as a replacement for the VMA prio_tree. The algorithms are similar to lib/interval_tree.c; however that code can't be directly reused as the interval endpoints are not explicitly stored in the VMA. So instead, the common algorithm is moved into a template and the details (node type, how to get interval endpoints from the node, etc) are filled in using the C preprocessor. Once the interval tree functions are available, using them as a replacement to the VMA prio tree is a relatively simple, mechanical job. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:25 +04:00
* Put into interval tree now, so instantiated pages
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
* are visible to arm/parisc __flush_dcache_page
* throughout; but we cannot insert into address
* space until vma start or end is updated.
*/
__vma_link_file(insert);
}
}
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
anon_vma = vma->anon_vma;
if (!anon_vma && adjust_next)
anon_vma = next->anon_vma;
if (anon_vma) {
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
VM_WARN_ON(adjust_next && next->anon_vma &&
anon_vma != next->anon_vma);
mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable rmap_walk_anon() and try_to_unmap_anon() appears to be too careful about locking the anon vma: while it needs protection against anon vma list modifications, it does not need exclusive access to the list itself. Transforming this exclusive lock to a read-locked rwsem removes a global lock from the hot path of page-migration intense threaded workloads which can cause pathological performance like this: 96.43% process 0 [kernel.kallsyms] [k] perf_trace_sched_switch | --- perf_trace_sched_switch __schedule schedule schedule_preempt_disabled __mutex_lock_common.isra.6 __mutex_lock_slowpath mutex_lock | |--50.61%-- rmap_walk | move_to_new_page | migrate_pages | migrate_misplaced_page | __do_numa_page.isra.69 | handle_pte_fault | handle_mm_fault | __do_page_fault | do_page_fault | page_fault | __memset_sse2 | | | --100.00%-- worker_thread | | | --100.00%-- start_thread | --49.39%-- page_lock_anon_vma try_to_unmap_anon try_to_unmap migrate_pages migrate_misplaced_page __do_numa_page.isra.69 handle_pte_fault handle_mm_fault __do_page_fault do_page_fault page_fault __memset_sse2 | --100.00%-- worker_thread start_thread With this change applied the profile is now nicely flat and there's no anon-vma related scheduling/blocking. Rename anon_vma_[un]lock() => anon_vma_[un]lock_write(), to make it clearer that it's an exclusive write-lock in that case - suggested by Rik van Riel. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Turner <pjt@google.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-02 23:56:50 +04:00
anon_vma_lock_write(anon_vma);
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
anon_vma_interval_tree_pre_update_vma(vma);
if (adjust_next)
anon_vma_interval_tree_pre_update_vma(next);
}
mm: always lock the root (oldest) anon_vma Always (and only) lock the root (oldest) anon_vma whenever we do something in an anon_vma. The recently introduced anon_vma scalability is due to the rmap code scanning only the VMAs that need to be scanned. Many common operations still took the anon_vma lock on the root anon_vma, so always taking that lock is not expected to introduce any scalability issues. However, always taking the same lock does mean we only need to take one lock, which means rmap_walk on pages from any anon_vma in the vma is excluded from occurring during an munmap, expand_stack or other operation that needs to exclude rmap_walk and similar functions. Also add the proper locking to vma_adjust. Signed-off-by: Rik van Riel <riel@redhat.com> Tested-by: Larry Woodman <lwoodman@redhat.com> Acked-by: Larry Woodman <lwoodman@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-10 04:18:40 +04:00
mm/mmap: check on file instead of the rb_root_cached of its address_space In __vma_adjust(), we do the check on *root* to decide whether to adjust the address_space. It seems to be more meaningful to do the check on *file* itself. This means we are adjusting some data because it is a file backed vma. Since we seem to assume the address_space is valid if it is a file backed vma, let's just replace *root* with *file* here. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200913133631.37781-2-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:54:07 +03:00
if (file) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
flush_dcache_mmap_lock(mapping);
mm: replace vma prio_tree with an interval tree Implement an interval tree as a replacement for the VMA prio_tree. The algorithms are similar to lib/interval_tree.c; however that code can't be directly reused as the interval endpoints are not explicitly stored in the VMA. So instead, the common algorithm is moved into a template and the details (node type, how to get interval endpoints from the node, etc) are filled in using the C preprocessor. Once the interval tree functions are available, using them as a replacement to the VMA prio tree is a relatively simple, mechanical job. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:25 +04:00
vma_interval_tree_remove(vma, root);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (adjust_next)
mm: replace vma prio_tree with an interval tree Implement an interval tree as a replacement for the VMA prio_tree. The algorithms are similar to lib/interval_tree.c; however that code can't be directly reused as the interval endpoints are not explicitly stored in the VMA. So instead, the common algorithm is moved into a template and the details (node type, how to get interval endpoints from the node, etc) are filled in using the C preprocessor. Once the interval tree functions are available, using them as a replacement to the VMA prio tree is a relatively simple, mechanical job. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:25 +04:00
vma_interval_tree_remove(next, root);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
if (start != vma->vm_start) {
vma->vm_start = start;
start_changed = true;
}
if (end != vma->vm_end) {
vma->vm_end = end;
end_changed = true;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
vma->vm_pgoff = pgoff;
if (adjust_next) {
mm/mmap: leave adjust_next as virtual address instead of page frame number Instead of converting adjust_next between bytes and pages number, let's just store the virtual address into adjust_next. Also, this patch fixes one typo in the comment of vma_adjust_trans_huge(). [vbabka@suse.cz: changelog tweak] Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mike Kravetz <mike.kravetz@oracle.com> Link: http://lkml.kernel.org/r/20200828081031.11306-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:53:57 +03:00
next->vm_start += adjust_next;
next->vm_pgoff += adjust_next >> PAGE_SHIFT;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm/mmap: check on file instead of the rb_root_cached of its address_space In __vma_adjust(), we do the check on *root* to decide whether to adjust the address_space. It seems to be more meaningful to do the check on *file* itself. This means we are adjusting some data because it is a file backed vma. Since we seem to assume the address_space is valid if it is a file backed vma, let's just replace *root* with *file* here. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200913133631.37781-2-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:54:07 +03:00
if (file) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (adjust_next)
mm: replace vma prio_tree with an interval tree Implement an interval tree as a replacement for the VMA prio_tree. The algorithms are similar to lib/interval_tree.c; however that code can't be directly reused as the interval endpoints are not explicitly stored in the VMA. So instead, the common algorithm is moved into a template and the details (node type, how to get interval endpoints from the node, etc) are filled in using the C preprocessor. Once the interval tree functions are available, using them as a replacement to the VMA prio tree is a relatively simple, mechanical job. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:25 +04:00
vma_interval_tree_insert(next, root);
vma_interval_tree_insert(vma, root);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
flush_dcache_mmap_unlock(mapping);
}
if (remove_next) {
/*
* vma_merge has merged next into vma, and needs
* us to remove next before dropping the locks.
*/
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
if (remove_next != 3)
mm/mmap: rename __vma_unlink_common() to __vma_unlink() __vma_unlink_common() and __vma_unlink() are counterparts. Since there is no function named __vma_unlink(), let's rename __vma_unlink_common() to __vma_unlink() to make the code more self-explanatory and easy for audience to understand. Otherwise we may expect there are several variants of vma_unlink() and __vma_unlink_common() is used by them. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200809232057.23477-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:53:32 +03:00
__vma_unlink(mm, next, next);
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
else
mm: vma_merge: correct false positive from __vma_unlink->validate_mm_rb The old code was always doing: vma->vm_end = next->vm_end vma_rb_erase(next) // in __vma_unlink vma->vm_next = next->vm_next // in __vma_unlink next = vma->vm_next vma_gap_update(next) The new code still does the above for remove_next == 1 and 2, but for remove_next == 3 it has been changed and it does: next->vm_start = vma->vm_start vma_rb_erase(vma) // in __vma_unlink vma_gap_update(next) In the latter case, while unlinking "vma", validate_mm_rb() is told to ignore "vma" that is being removed, but next->vm_start was reduced instead. So for the new case, to avoid the false positive from validate_mm_rb, it should be "next" that is ignored when "vma" is being unlinked. "vma" and "next" in the above comment, considered pre-swap(). Link: http://lkml.kernel.org/r/1474492522-2261-4-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:37 +03:00
/*
* vma is not before next if they've been
* swapped.
*
* pre-swap() next->vm_start was reduced so
* tell validate_mm_rb to ignore pre-swap()
* "next" (which is stored in post-swap()
* "vma").
*/
mm/mmap: rename __vma_unlink_common() to __vma_unlink() __vma_unlink_common() and __vma_unlink() are counterparts. Since there is no function named __vma_unlink(), let's rename __vma_unlink_common() to __vma_unlink() to make the code more self-explanatory and easy for audience to understand. Otherwise we may expect there are several variants of vma_unlink() and __vma_unlink_common() is used by them. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200809232057.23477-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:53:32 +03:00
__vma_unlink(mm, next, vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (file)
__remove_shared_vm_struct(next, file, mapping);
} else if (insert) {
/*
* split_vma has split insert from vma, and needs
* us to insert it before dropping the locks
* (it may either follow vma or precede it).
*/
__insert_vm_struct(mm, insert);
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
} else {
if (start_changed)
vma_gap_update(vma);
if (end_changed) {
if (!next)
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
mm->highest_vm_end = vm_end_gap(vma);
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
else if (!adjust_next)
vma_gap_update(next);
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
if (anon_vma) {
anon_vma_interval_tree_post_update_vma(vma);
if (adjust_next)
anon_vma_interval_tree_post_update_vma(next);
mm/rmap: rename anon_vma_unlock() => anon_vma_unlock_write() The comment in commit 4fc3f1d66b1e ("mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable") says: | Rename anon_vma_[un]lock() => anon_vma_[un]lock_write(), | to make it clearer that it's an exclusive write-lock in | that case - suggested by Rik van Riel. But that commit renames only anon_vma_lock() Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Ingo Molnar <mingo@kernel.org> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:34:40 +04:00
anon_vma_unlock_write(anon_vma);
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm/mmap: check on file instead of the rb_root_cached of its address_space In __vma_adjust(), we do the check on *root* to decide whether to adjust the address_space. It seems to be more meaningful to do the check on *file* itself. This means we are adjusting some data because it is a file backed vma. Since we seem to assume the address_space is valid if it is a file backed vma, let's just replace *root* with *file* here. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200913133631.37781-2-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:54:07 +03:00
if (file) {
mm/mmap: not necessary to check mapping separately *root* with type of struct rb_root_cached is an element of *mapping* with type of struct address_space. This implies when we have a valid *root* it must be a part of valid *mapping*. So we can merge these two checks together to make the code more easy to read and to save some cpu cycles. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200913133631.37781-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:54:04 +03:00
i_mmap_unlock_write(mapping);
uprobes/core: Clean up, refactor and improve the code Make the uprobes code readable to me: - improve the Kconfig text so that a mere mortal gets some idea what CONFIG_UPROBES=y is really about - do trivial renames to standardize around the uprobes_*() namespace - clean up and simplify various code flow details - separate basic blocks of functionality - line break artifact and white space related removal - use standard local varible definition blocks - use vertical spacing to make things more readable - remove unnecessary volatile - restructure comment blocks to make them more uniform and more readable in general Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Link: http://lkml.kernel.org/n/tip-ewbwhb8o6navvllsauu7k07p@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-17 12:27:41 +04:00
uprobe_mmap(vma);
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 13:26:42 +04:00
if (adjust_next)
uprobes/core: Clean up, refactor and improve the code Make the uprobes code readable to me: - improve the Kconfig text so that a mere mortal gets some idea what CONFIG_UPROBES=y is really about - do trivial renames to standardize around the uprobes_*() namespace - clean up and simplify various code flow details - separate basic blocks of functionality - line break artifact and white space related removal - use standard local varible definition blocks - use vertical spacing to make things more readable - remove unnecessary volatile - restructure comment blocks to make them more uniform and more readable in general Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Link: http://lkml.kernel.org/n/tip-ewbwhb8o6navvllsauu7k07p@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-17 12:27:41 +04:00
uprobe_mmap(next);
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 13:26:42 +04:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (remove_next) {
procfs task exe symlink The kernel implements readlink of /proc/pid/exe by getting the file from the first executable VMA. Then the path to the file is reconstructed and reported as the result. Because of the VMA walk the code is slightly different on nommu systems. This patch avoids separate /proc/pid/exe code on nommu systems. Instead of walking the VMAs to find the first executable file-backed VMA we store a reference to the exec'd file in the mm_struct. That reference would prevent the filesystem holding the executable file from being unmounted even after unmapping the VMAs. So we track the number of VM_EXECUTABLE VMAs and drop the new reference when the last one is unmapped. This avoids pinning the mounted filesystem. [akpm@linux-foundation.org: improve comments] [yamamoto@valinux.co.jp: fix dup_mmap] Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: David Howells <dhowells@redhat.com> Cc:"Eric W. Biederman" <ebiederm@xmission.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:01:36 +04:00
if (file) {
uprobes/core: Decrement uprobe count before the pages are unmapped Uprobes has a callback (uprobe_munmap()) in the unmap path to maintain the uprobes count. In the exit path this callback gets called in unlink_file_vma(). However by the time unlink_file_vma() is called, the pages would have been unmapped (in unmap_vmas()) and the task->rss_stat counts accounted (in zap_pte_range()). If the exiting process has probepoints, uprobe_munmap() checks if the breakpoint instruction was around before decrementing the probe count. This results in a file backed page being reread by uprobe_munmap() and hence it does not find the breakpoint. This patch fixes this problem by moving the callback to unmap_single_vma(). Since unmap_single_vma() may not unmap the complete vma, add start and end parameters to uprobe_munmap(). This bug became apparent courtesy of commit c3f0327f8e9d ("mm: add rss counters consistency check"). Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com> Cc: Linux-mm <linux-mm@kvack.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Anton Arapov <anton@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20120411103527.23245.9835.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-04-11 14:35:27 +04:00
uprobe_munmap(next, next->vm_start, next->vm_end);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
fput(file);
procfs task exe symlink The kernel implements readlink of /proc/pid/exe by getting the file from the first executable VMA. Then the path to the file is reconstructed and reported as the result. Because of the VMA walk the code is slightly different on nommu systems. This patch avoids separate /proc/pid/exe code on nommu systems. Instead of walking the VMAs to find the first executable file-backed VMA we store a reference to the exec'd file in the mm_struct. That reference would prevent the filesystem holding the executable file from being unmounted even after unmapping the VMAs. So we track the number of VM_EXECUTABLE VMAs and drop the new reference when the last one is unmapped. This avoids pinning the mounted filesystem. [akpm@linux-foundation.org: improve comments] [yamamoto@valinux.co.jp: fix dup_mmap] Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: David Howells <dhowells@redhat.com> Cc:"Eric W. Biederman" <ebiederm@xmission.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:01:36 +04:00
}
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
if (next->anon_vma)
anon_vma_merge(vma, next);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm->map_count--;
mm: mempolicy: fix mbind_range() && vma_adjust() interaction vma_adjust() does vma_set_policy(vma, vma_policy(next)) and this is doubly wrong: 1. This leaks vma->vm_policy if it is not NULL and not equal to next->vm_policy. This can happen if vma_merge() expands "area", not prev (case 8). 2. This sets the wrong policy if vma_merge() joins prev and area, area is the vma the caller needs to update and it still has the old policy. Revert commit 1444f92c8498 ("mm: merging memory blocks resets mempolicy") which introduced these problems. Change mbind_range() to recheck mpol_equal() after vma_merge() to fix the problem that commit tried to address. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Steven T Hampson <steven.t.hampson@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-08-01 00:53:28 +04:00
mpol_put(vma_policy(next));
mm: use helper functions for allocating and freeing vm_area structs The vm_area_struct is one of the most fundamental memory management objects, but the management of it is entirely open-coded evertwhere, ranging from allocation and freeing (using kmem_cache_[z]alloc and kmem_cache_free) to initializing all the fields. We want to unify this in order to end up having some unified initialization of the vmas, and the first step to this is to at least have basic allocation functions. Right now those functions are literally just wrappers around the kmem_cache_*() calls. This is a purely mechanical conversion: # new vma: kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc() # copy old vma kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old) # free vma kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma) to the point where the old vma passed in to the vm_area_dup() function isn't even used yet (because I've left all the old manual initialization alone). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-21 23:48:51 +03:00
vm_area_free(next);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* In mprotect's case 6 (see comments on vma_merge),
* we must remove another next too. It would clutter
* up the code too much to do both in one go.
*/
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
if (remove_next != 3) {
/*
* If "next" was removed and vma->vm_end was
* expanded (up) over it, in turn
* "next->vm_prev->vm_end" changed and the
* "vma->vm_next" gap must be updated.
*/
next = vma->vm_next;
} else {
/*
* For the scope of the comment "next" and
* "vma" considered pre-swap(): if "vma" was
* removed, next->vm_start was expanded (down)
* over it and the "next" gap must be updated.
* Because of the swap() the post-swap() "vma"
* actually points to pre-swap() "next"
* (post-swap() "next" as opposed is now a
* dangling pointer).
*/
next = vma;
}
mm: fix use-after-free if memory allocation failed in vma_adjust() There's one case when vma_adjust() expands the vma, overlapping with *two* next vma. See case 6 of mprotect, described in the comment to vma_merge(). To handle this (and only this) situation we iterate twice over main part of the function. See "goto again". Vegard reported[1] that he sees out-of-bounds access complain from KASAN, if anon_vma_clone() on the *second* iteration fails. This happens because we free 'next' vma by the end of first iteration and don't have a way to undo this if anon_vma_clone() fails on the second iteration. The solution is to do all required allocations upfront, before we touch vmas. The allocation on the second iteration is only required if first two vmas don't have anon_vma, but third does. So we need, in total, one anon_vma_clone() call. It's easy to adjust 'exporter' to the third vma for such case. [1] http://lkml.kernel.org/r/1469514843-23778-1-git-send-email-vegard.nossum@oracle.com Link: http://lkml.kernel.org/r/1469625255-126641-1-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29 01:49:01 +03:00
if (remove_next == 2) {
remove_next = 1;
end = next->vm_end;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
goto again;
mm: fix use-after-free if memory allocation failed in vma_adjust() There's one case when vma_adjust() expands the vma, overlapping with *two* next vma. See case 6 of mprotect, described in the comment to vma_merge(). To handle this (and only this) situation we iterate twice over main part of the function. See "goto again". Vegard reported[1] that he sees out-of-bounds access complain from KASAN, if anon_vma_clone() on the *second* iteration fails. This happens because we free 'next' vma by the end of first iteration and don't have a way to undo this if anon_vma_clone() fails on the second iteration. The solution is to do all required allocations upfront, before we touch vmas. The allocation on the second iteration is only required if first two vmas don't have anon_vma, but third does. So we need, in total, one anon_vma_clone() call. It's easy to adjust 'exporter' to the third vma for such case. [1] http://lkml.kernel.org/r/1469514843-23778-1-git-send-email-vegard.nossum@oracle.com Link: http://lkml.kernel.org/r/1469625255-126641-1-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29 01:49:01 +03:00
}
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
else if (next)
vma_gap_update(next);
mm: vma_adjust: remove superfluous confusing update in remove_next == 1 case mm->highest_vm_end doesn't need any update. After finally removing the oddness from vma_merge case 8 that was causing: 1) constant risk of trouble whenever anybody would check vma fields from rmap_walks, like it happened when page migration was introduced and it read the vma->vm_page_prot from a rmap_walk 2) the callers of vma_merge to re-initialize any value different from the current vma, instead of vma_merge() more reliably returning a vma that already matches all fields passed as parameter .. it is also worth to take the opportunity of cleaning up superfluous code in vma_adjust(), that if not removed adds up to the hard readability of the function. Link: http://lkml.kernel.org/r/1474492522-2261-5-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:25 +03:00
else {
/*
* If remove_next == 2 we obviously can't
* reach this path.
*
* If remove_next == 3 we can't reach this
* path because pre-swap() next is always not
* NULL. pre-swap() "next" is not being
* removed and its next->vm_end is not altered
* (and furthermore "end" already matches
* next->vm_end in remove_next == 3).
*
* We reach this only in the remove_next == 1
* case if the "next" vma that was removed was
* the highest vma of the mm. However in such
* case next->vm_end == "end" and the extended
* "vma" has vma->vm_end == next->vm_end so
* mm->highest_vm_end doesn't need any update
* in remove_next == 1 case.
*/
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma));
mm: vma_adjust: remove superfluous confusing update in remove_next == 1 case mm->highest_vm_end doesn't need any update. After finally removing the oddness from vma_merge case 8 that was causing: 1) constant risk of trouble whenever anybody would check vma fields from rmap_walks, like it happened when page migration was introduced and it read the vma->vm_page_prot from a rmap_walk 2) the callers of vma_merge to re-initialize any value different from the current vma, instead of vma_merge() more reliably returning a vma that already matches all fields passed as parameter .. it is also worth to take the opportunity of cleaning up superfluous code in vma_adjust(), that if not removed adds up to the hard readability of the function. Link: http://lkml.kernel.org/r/1474492522-2261-5-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:25 +03:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 13:26:42 +04:00
if (insert && file)
uprobes/core: Clean up, refactor and improve the code Make the uprobes code readable to me: - improve the Kconfig text so that a mere mortal gets some idea what CONFIG_UPROBES=y is really about - do trivial renames to standardize around the uprobes_*() namespace - clean up and simplify various code flow details - separate basic blocks of functionality - line break artifact and white space related removal - use standard local varible definition blocks - use vertical spacing to make things more readable - remove unnecessary volatile - restructure comment blocks to make them more uniform and more readable in general Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Link: http://lkml.kernel.org/n/tip-ewbwhb8o6navvllsauu7k07p@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-17 12:27:41 +04:00
uprobe_mmap(insert);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
validate_mm(mm);
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
return 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/*
* If the vma has a ->close operation then the driver probably needs to release
* per-vma resources, so we don't attempt to merge those.
*/
static inline int is_mergeable_vma(struct vm_area_struct *vma,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
struct file *file, unsigned long vm_flags,
struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm: ignore VM_SOFTDIRTY on VMA merging The VM_SOFTDIRTY bit affects vma merge routine: if two VMAs has all bits in vm_flags matched except dirty bit the kernel can't longer merge them and this forces the kernel to generate new VMAs instead. It finally may lead to the situation when userspace application reaches vm.max_map_count limit and get crashed in worse case | (gimp:11768): GLib-ERROR **: gmem.c:110: failed to allocate 4096 bytes | | (file-tiff-load:12038): LibGimpBase-WARNING **: file-tiff-load: gimp_wire_read(): error | xinit: connection to X server lost | | waiting for X server to shut down | /usr/lib64/gimp/2.0/plug-ins/file-tiff-load terminated: Hangup | /usr/lib64/gimp/2.0/plug-ins/script-fu terminated: Hangup | /usr/lib64/gimp/2.0/plug-ins/script-fu terminated: Hangup https://bugzilla.kernel.org/show_bug.cgi?id=67651 https://bugzilla.gnome.org/show_bug.cgi?id=719619#c0 Initial problem came from missed VM_SOFTDIRTY in do_brk() routine but even if we would set up VM_SOFTDIRTY here, there is still a way to prevent VMAs from merging: one can call | echo 4 > /proc/$PID/clear_refs and clear all VM_SOFTDIRTY over all VMAs presented in memory map, then new do_brk() will try to extend old VMA and finds that dirty bit doesn't match thus new VMA will be generated. As discussed with Pavel, the right approach should be to ignore VM_SOFTDIRTY bit when we're trying to merge VMAs and if merge successed we mark extended VMA with dirty bit where needed. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Reported-by: Bastian Hougaard <gnome@rvzt.net> Reported-by: Mel Gorman <mgorman@suse.de> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-24 03:53:42 +04:00
/*
* VM_SOFTDIRTY should not prevent from VMA merging, if we
* match the flags but dirty bit -- the caller should mark
* merged VMA as dirty. If dirty bit won't be excluded from
mm: fix some typos in mm directory No functional change. Link: http://lkml.kernel.org/r/20190118235123.27843-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-06 02:46:22 +03:00
* comparison, we increase pressure on the memory system forcing
mm: ignore VM_SOFTDIRTY on VMA merging The VM_SOFTDIRTY bit affects vma merge routine: if two VMAs has all bits in vm_flags matched except dirty bit the kernel can't longer merge them and this forces the kernel to generate new VMAs instead. It finally may lead to the situation when userspace application reaches vm.max_map_count limit and get crashed in worse case | (gimp:11768): GLib-ERROR **: gmem.c:110: failed to allocate 4096 bytes | | (file-tiff-load:12038): LibGimpBase-WARNING **: file-tiff-load: gimp_wire_read(): error | xinit: connection to X server lost | | waiting for X server to shut down | /usr/lib64/gimp/2.0/plug-ins/file-tiff-load terminated: Hangup | /usr/lib64/gimp/2.0/plug-ins/script-fu terminated: Hangup | /usr/lib64/gimp/2.0/plug-ins/script-fu terminated: Hangup https://bugzilla.kernel.org/show_bug.cgi?id=67651 https://bugzilla.gnome.org/show_bug.cgi?id=719619#c0 Initial problem came from missed VM_SOFTDIRTY in do_brk() routine but even if we would set up VM_SOFTDIRTY here, there is still a way to prevent VMAs from merging: one can call | echo 4 > /proc/$PID/clear_refs and clear all VM_SOFTDIRTY over all VMAs presented in memory map, then new do_brk() will try to extend old VMA and finds that dirty bit doesn't match thus new VMA will be generated. As discussed with Pavel, the right approach should be to ignore VM_SOFTDIRTY bit when we're trying to merge VMAs and if merge successed we mark extended VMA with dirty bit where needed. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Reported-by: Bastian Hougaard <gnome@rvzt.net> Reported-by: Mel Gorman <mgorman@suse.de> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-24 03:53:42 +04:00
* the kernel to generate new VMAs when old one could be
* extended instead.
*/
if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return 0;
if (vma->vm_file != file)
return 0;
if (vma->vm_ops && vma->vm_ops->close)
return 0;
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
return 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return 1;
}
static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
mmap: avoid merging cloned VMAs Avoid merging a VMA with another VMA which is cloned from the parent process. The cloned VMA shares the anon_vma lock with the parent process's VMA. If we do the merge, more vmas (even the new range is only for current process) use the perent process's anon_vma lock. This introduces scalability issues. find_mergeable_anon_vma() already considers this case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:20 +04:00
struct anon_vma *anon_vma2,
struct vm_area_struct *vma)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mmap: avoid merging cloned VMAs Avoid merging a VMA with another VMA which is cloned from the parent process. The cloned VMA shares the anon_vma lock with the parent process's VMA. If we do the merge, more vmas (even the new range is only for current process) use the perent process's anon_vma lock. This introduces scalability issues. find_mergeable_anon_vma() already considers this case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:20 +04:00
/*
* The list_is_singular() test is to avoid merging VMA cloned from
* parents. This can improve scalability caused by anon_vma lock.
*/
if ((!anon_vma1 || !anon_vma2) && (!vma ||
list_is_singular(&vma->anon_vma_chain)))
return 1;
return anon_vma1 == anon_vma2;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/*
* Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
* in front of (at a lower virtual address and file offset than) the vma.
*
* We cannot merge two vmas if they have differently assigned (non-NULL)
* anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
*
* We don't check here for the merged mmap wrapping around the end of pagecache
mm: remove unnecessary wrapper function do_mmap_pgoff() The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db7f82 ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:37 +03:00
* indices (16TB on ia32) because do_mmap() does not permit mmap's which
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
* wrap, nor mmaps which cover the final page at index -1UL.
*/
static int
can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
struct anon_vma *anon_vma, struct file *file,
pgoff_t vm_pgoff,
struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) &&
mmap: avoid merging cloned VMAs Avoid merging a VMA with another VMA which is cloned from the parent process. The cloned VMA shares the anon_vma lock with the parent process's VMA. If we do the merge, more vmas (even the new range is only for current process) use the perent process's anon_vma lock. This introduces scalability issues. find_mergeable_anon_vma() already considers this case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:20 +04:00
is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (vma->vm_pgoff == vm_pgoff)
return 1;
}
return 0;
}
/*
* Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
* beyond (at a higher virtual address and file offset than) the vma.
*
* We cannot merge two vmas if they have differently assigned (non-NULL)
* anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
*/
static int
can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
struct anon_vma *anon_vma, struct file *file,
pgoff_t vm_pgoff,
struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) &&
mmap: avoid merging cloned VMAs Avoid merging a VMA with another VMA which is cloned from the parent process. The cloned VMA shares the anon_vma lock with the parent process's VMA. If we do the merge, more vmas (even the new range is only for current process) use the perent process's anon_vma lock. This introduces scalability issues. find_mergeable_anon_vma() already considers this case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:20 +04:00
is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
pgoff_t vm_pglen;
mm: use vma_pages() to replace (vm_end - vm_start) >> PAGE_SHIFT (*->vm_end - *->vm_start) >> PAGE_SHIFT operation is implemented as a inline funcion vma_pages() in linux/mm.h, so using it. Signed-off-by: Libin <huawei.libin@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-04 02:01:26 +04:00
vm_pglen = vma_pages(vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (vma->vm_pgoff + vm_pglen == vm_pgoff)
return 1;
}
return 0;
}
/*
* Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
* whether that can be merged with its predecessor or its successor.
* Or both (it neatly fills a hole).
*
* In most cases - when called for mmap, brk or mremap - [addr,end) is
* certain not to be mapped by the time vma_merge is called; but when
* called for mprotect, it is certain to be already mapped (either at
* an offset within prev, or at the start of next), and the flags of
* this area are about to be changed to vm_flags - and the no-change
* case has already been eliminated.
*
* The following mprotect cases have to be considered, where AAAA is
* the area passed down from mprotect_fixup, never extending beyond one
* vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
*
mm/mmap.c: make vma_merge() comment more easy to understand Case 1/6, 2/7 and 3/8 have the same pattern and we handle them in the same logic. Rearrange the comment to make it a little easy for audience to understand. Link: http://lkml.kernel.org/r/20191030012445.16944-1-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Steve Capper <steve.capper@arm.com> Cc: Michel Lespinasse <walken@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Yangtao Li <tiny.windzz@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 04:57:39 +03:00
* AAAA AAAA AAAA
* PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN
* cannot merge might become might become
* PPNNNNNNNNNN PPPPPPPPPPNN
* mmap, brk or case 4 below case 5 below
* mremap move:
* AAAA AAAA
* PPPP NNNN PPPPNNNNXXXX
* might become might become
* PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or
* PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or
* PPPPNNNNNNNN 3 PPPPXXXXXXXX 8
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*
mm: fix some typos in mm directory No functional change. Link: http://lkml.kernel.org/r/20190118235123.27843-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-06 02:46:22 +03:00
* It is important for case 8 that the vma NNNN overlapping the
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
* region AAAA is never going to extended over XXXX. Instead XXXX must
* be extended in region AAAA and NNNN must be removed. This way in
* all cases where vma_merge succeeds, the moment vma_adjust drops the
* rmap_locks, the properties of the merged vma will be already
* correct for the whole merged range. Some of those properties like
* vm_page_prot/vm_flags may be accessed by rmap_walks and they must
* be correct for the whole merged range immediately after the
* rmap_locks are released. Otherwise if XXXX would be removed and
* NNNN would be extended over the XXXX range, remove_migration_ptes
* or other rmap walkers (if working on addresses beyond the "end"
* parameter) may establish ptes with the wrong permissions of NNNN
* instead of the right permissions of XXXX.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
struct vm_area_struct *vma_merge(struct mm_struct *mm,
struct vm_area_struct *prev, unsigned long addr,
unsigned long end, unsigned long vm_flags,
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
struct anon_vma *anon_vma, struct file *file,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
pgoff_t pgoff, struct mempolicy *policy,
struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
struct vm_area_struct *area, *next;
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
int err;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* We later require that vma->vm_flags == vm_flags,
* so this tests vma->vm_flags & VM_SPECIAL, too.
*/
if (vm_flags & VM_SPECIAL)
return NULL;
mm/mmap: add inline vma_next() for readability of mmap code There are three places that the next vma is required which uses the same block of code. Replace the block with a function and add comments on what happens in the case where NULL is encountered. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200818154707.2515169-1-Liam.Howlett@Oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 02:14:06 +03:00
next = vma_next(mm, prev);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
area = next;
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
if (area && area->vm_end == end) /* cases 6, 7, 8 */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
next = next->vm_next;
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
/* verify some invariant that must be enforced by the caller */
VM_WARN_ON(prev && addr <= prev->vm_start);
VM_WARN_ON(area && end > area->vm_end);
VM_WARN_ON(addr >= end);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* Can it merge with the predecessor?
*/
if (prev && prev->vm_end == addr &&
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
mpol_equal(vma_policy(prev), policy) &&
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
can_vma_merge_after(prev, vm_flags,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
anon_vma, file, pgoff,
vm_userfaultfd_ctx)) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* OK, it can. Can we now merge in the successor as well?
*/
if (next && end == next->vm_start &&
mpol_equal(policy, vma_policy(next)) &&
can_vma_merge_before(next, vm_flags,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
anon_vma, file,
pgoff+pglen,
vm_userfaultfd_ctx) &&
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
is_mergeable_anon_vma(prev->anon_vma,
mmap: avoid merging cloned VMAs Avoid merging a VMA with another VMA which is cloned from the parent process. The cloned VMA shares the anon_vma lock with the parent process's VMA. If we do the merge, more vmas (even the new range is only for current process) use the perent process's anon_vma lock. This introduces scalability issues. find_mergeable_anon_vma() already considers this case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:20 +04:00
next->anon_vma, NULL)) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* cases 1, 6 */
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
err = __vma_adjust(prev, prev->vm_start,
next->vm_end, prev->vm_pgoff, NULL,
prev);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
} else /* cases 2, 5, 7 */
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
err = __vma_adjust(prev, prev->vm_start,
end, prev->vm_pgoff, NULL, prev);
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
if (err)
return NULL;
mm, thp: fix collapsing of hugepages on madvise If an anonymous mapping is not allowed to fault thp memory and then madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never collapse this memory into thp memory. This occurs because the madvise(2) handler for thp, hugepage_madvise(), clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags until the final action of madvise_behavior(). This causes the khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when the vma had previously had VM_NOHUGEPAGE set. Fix this by passing the correct vma flags to the khugepaged mm slot handler. There's no chance khugepaged can run on this vma until after madvise_behavior() returns since we hold mm->mmap_sem. It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags in hugepage_advise(), but I didn't want to introduce special case behavior into madvise_behavior(). I think it's best to just let it always set vma->vm_flags itself. Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Suleiman Souhlal <suleiman@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-30 00:50:31 +03:00
khugepaged_enter_vma_merge(prev, vm_flags);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return prev;
}
/*
* Can this new request be merged in front of next?
*/
if (next && end == next->vm_start &&
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
mpol_equal(policy, vma_policy(next)) &&
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
can_vma_merge_before(next, vm_flags,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
anon_vma, file, pgoff+pglen,
vm_userfaultfd_ctx)) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (prev && addr < prev->vm_end) /* case 4 */
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk The rmap_walk can access vm_page_prot (and potentially vm_flags in the pte/pmd manipulations). So it's not safe to wait the caller to update the vm_page_prot/vm_flags after vma_merge returned potentially removing the "next" vma and extending the "current" vma over the next->vm_start,vm_end range, but still with the "current" vma vm_page_prot, after releasing the rmap locks. The vm_page_prot/vm_flags must be transferred from the "next" vma to the current vma while vma_merge still holds the rmap locks. The side effect of this race condition is pte corruption during migrate as remove_migration_ptes when run on a address of the "next" vma that got removed, used the vm_page_prot of the current vma. migrate mprotect ------------ ------------- migrating in "next" vma vma_merge() # removes "next" vma and # extends "current" vma # current vma is not with # vm_page_prot updated remove_migration_ptes read vm_page_prot of current "vma" establish pte with wrong permissions vm_set_page_prot(vma) # too late! change_protection in the old vma range only, next range is not updated This caused segmentation faults and potentially memory corruption in heavy mprotect loads with some light page migration caused by compaction in the background. Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge which confirms the case 8 is only buggy one where the race can trigger, in all other vma_merge cases the above cannot happen. This fix removes the oddness factor from case 8 and it converts it from: AAAA PPPPNNNNXXXX -> PPPPNNNNNNNN to: AAAA PPPPNNNNXXXX -> PPPPXXXXXXXX XXXX has the right vma properties for the whole merged vma returned by vma_adjust, so it solves the problem fully. It has the added benefits that the callers could stop updating vma properties when vma_merge succeeds however the callers are not updated by this patch (there are bits like VM_SOFTDIRTY that still need special care for the whole range, as the vma merging ignores them, but as long as they're not processed by rmap walks and instead they're accessed with the mmap_sem at least for reading, they are fine not to be updated within vma_adjust before releasing the rmap_locks). Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Aditya Mandaleeka <adityam@microsoft.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:28 +03:00
err = __vma_adjust(prev, prev->vm_start,
addr, prev->vm_pgoff, NULL, next);
else { /* cases 3, 8 */
err = __vma_adjust(area, addr, next->vm_end,
next->vm_pgoff - pglen, NULL, next);
/*
* In case 3 area is already equal to next and
* this is a noop, but in case 8 "area" has
* been removed and next was expanded over it.
*/
area = next;
}
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
if (err)
return NULL;
mm, thp: fix collapsing of hugepages on madvise If an anonymous mapping is not allowed to fault thp memory and then madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never collapse this memory into thp memory. This occurs because the madvise(2) handler for thp, hugepage_madvise(), clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags until the final action of madvise_behavior(). This causes the khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when the vma had previously had VM_NOHUGEPAGE set. Fix this by passing the correct vma flags to the khugepaged mm slot handler. There's no chance khugepaged can run on this vma until after madvise_behavior() returns since we hold mm->mmap_sem. It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags in hugepage_advise(), but I didn't want to introduce special case behavior into madvise_behavior(). I think it's best to just let it always set vma->vm_flags itself. Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Suleiman Souhlal <suleiman@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-30 00:50:31 +03:00
khugepaged_enter_vma_merge(area, vm_flags);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return area;
}
return NULL;
}
Simplify and comment on anon_vma re-use for anon_vma_prepare() This changes the anon_vma reuse case to require that we only reuse simple anon_vma's - ie the case when the vma only has a single anon_vma associated with it. This means that a reuse of an anon_vma from an adjacent vma will always guarantee that both vma's are associated not only with the same anon_vma, they will also have the same anon_vma chain (of just a single entry in this case). And since anon_vma re-use was the only case where the same anon_vma might be associated with different chains of anon_vma's, we now have the case that every vma that shares the same anon_vma will always also have the same chain. That makes it much easier to think about merging vma's that share the same anon_vma's: you can always just drop the other anon_vma chain in anon_vma_merge() since you know that they are always identical. This also splits up the function to validate the anon_vma re-use, and adds a lot of commentary about the possible races. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "That didn't fix it" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-10 21:36:19 +04:00
/*
mm: mmap: fix a typo in comment "compatbility"->"compatibility" There is a typo in comment, fix it. Signed-off-by: Ethon Paul <ethp@qq.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Link: http://lkml.kernel.org/r/20200410163206.14016-1-ethp@qq.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-05 02:49:04 +03:00
* Rough compatibility check to quickly see if it's even worth looking
Simplify and comment on anon_vma re-use for anon_vma_prepare() This changes the anon_vma reuse case to require that we only reuse simple anon_vma's - ie the case when the vma only has a single anon_vma associated with it. This means that a reuse of an anon_vma from an adjacent vma will always guarantee that both vma's are associated not only with the same anon_vma, they will also have the same anon_vma chain (of just a single entry in this case). And since anon_vma re-use was the only case where the same anon_vma might be associated with different chains of anon_vma's, we now have the case that every vma that shares the same anon_vma will always also have the same chain. That makes it much easier to think about merging vma's that share the same anon_vma's: you can always just drop the other anon_vma chain in anon_vma_merge() since you know that they are always identical. This also splits up the function to validate the anon_vma re-use, and adds a lot of commentary about the possible races. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "That didn't fix it" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-10 21:36:19 +04:00
* at sharing an anon_vma.
*
* They need to have the same vm_file, and the flags can only differ
* in things that mprotect may change.
*
* NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
* we can merge the two vma's. For example, we refuse to merge a vma if
* there is a vm_ops->close() function, because that indicates that the
* driver is doing some kind of reference counting. But that doesn't
* really matter for the anon_vma sharing case.
*/
static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
{
return a->vm_end == b->vm_start &&
mpol_equal(vma_policy(a), vma_policy(b)) &&
a->vm_file == b->vm_file &&
mm/vma: introduce VM_ACCESS_FLAGS There are many places where all basic VMA access flags (read, write, exec) are initialized or checked against as a group. One such example is during page fault. Existing vma_is_accessible() wrapper already creates the notion of VMA accessibility as a group access permissions. Hence lets just create VM_ACCESS_FLAGS (VM_READ|VM_WRITE|VM_EXEC) which will not only reduce code duplication but also extend the VMA accessibility concept in general. Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Salter <msalter@redhat.com> Cc: Nick Hu <nickhu@andestech.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Rob Springer <rspringer@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Link: http://lkml.kernel.org/r/1583391014-8170-3-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-11 00:33:09 +03:00
!((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) &&
Simplify and comment on anon_vma re-use for anon_vma_prepare() This changes the anon_vma reuse case to require that we only reuse simple anon_vma's - ie the case when the vma only has a single anon_vma associated with it. This means that a reuse of an anon_vma from an adjacent vma will always guarantee that both vma's are associated not only with the same anon_vma, they will also have the same anon_vma chain (of just a single entry in this case). And since anon_vma re-use was the only case where the same anon_vma might be associated with different chains of anon_vma's, we now have the case that every vma that shares the same anon_vma will always also have the same chain. That makes it much easier to think about merging vma's that share the same anon_vma's: you can always just drop the other anon_vma chain in anon_vma_merge() since you know that they are always identical. This also splits up the function to validate the anon_vma re-use, and adds a lot of commentary about the possible races. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "That didn't fix it" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-10 21:36:19 +04:00
b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
}
/*
* Do some basic sanity checking to see if we can re-use the anon_vma
* from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
* the same as 'old', the other will be the new one that is trying
* to share the anon_vma.
*
* NOTE! This runs with mm_sem held for reading, so it is possible that
* the anon_vma of 'old' is concurrently in the process of being set up
* by another page fault trying to merge _that_. But that's ok: if it
* is being set up, that automatically means that it will be a singleton
* acceptable for merging, so we can do all of this optimistically. But
mm: remove rest of ACCESS_ONCE() usages We converted some of the usages of ACCESS_ONCE to READ_ONCE in the mm/ tree since it doesn't work reliably on non-scalar types. This patch removes the rest of the usages of ACCESS_ONCE, and use the new READ_ONCE API for the read accesses. This makes things cleaner, instead of using separate/multiple sets of APIs. Signed-off-by: Jason Low <jason.low2@hp.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-16 02:14:08 +03:00
* we do that READ_ONCE() to make sure that we never re-load the pointer.
Simplify and comment on anon_vma re-use for anon_vma_prepare() This changes the anon_vma reuse case to require that we only reuse simple anon_vma's - ie the case when the vma only has a single anon_vma associated with it. This means that a reuse of an anon_vma from an adjacent vma will always guarantee that both vma's are associated not only with the same anon_vma, they will also have the same anon_vma chain (of just a single entry in this case). And since anon_vma re-use was the only case where the same anon_vma might be associated with different chains of anon_vma's, we now have the case that every vma that shares the same anon_vma will always also have the same chain. That makes it much easier to think about merging vma's that share the same anon_vma's: you can always just drop the other anon_vma chain in anon_vma_merge() since you know that they are always identical. This also splits up the function to validate the anon_vma re-use, and adds a lot of commentary about the possible races. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "That didn't fix it" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-10 21:36:19 +04:00
*
* IOW: that the "list_is_singular()" test on the anon_vma_chain only
* matters for the 'stable anon_vma' case (ie the thing we want to avoid
* is to return an anon_vma that is "complex" due to having gone through
* a fork).
*
* We also make sure that the two vma's are compatible (adjacent,
* and with the same memory policies). That's all stable, even with just
* a read lock on the mm_sem.
*/
static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
{
if (anon_vma_compatible(a, b)) {
mm: remove rest of ACCESS_ONCE() usages We converted some of the usages of ACCESS_ONCE to READ_ONCE in the mm/ tree since it doesn't work reliably on non-scalar types. This patch removes the rest of the usages of ACCESS_ONCE, and use the new READ_ONCE API for the read accesses. This makes things cleaner, instead of using separate/multiple sets of APIs. Signed-off-by: Jason Low <jason.low2@hp.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-16 02:14:08 +03:00
struct anon_vma *anon_vma = READ_ONCE(old->anon_vma);
Simplify and comment on anon_vma re-use for anon_vma_prepare() This changes the anon_vma reuse case to require that we only reuse simple anon_vma's - ie the case when the vma only has a single anon_vma associated with it. This means that a reuse of an anon_vma from an adjacent vma will always guarantee that both vma's are associated not only with the same anon_vma, they will also have the same anon_vma chain (of just a single entry in this case). And since anon_vma re-use was the only case where the same anon_vma might be associated with different chains of anon_vma's, we now have the case that every vma that shares the same anon_vma will always also have the same chain. That makes it much easier to think about merging vma's that share the same anon_vma's: you can always just drop the other anon_vma chain in anon_vma_merge() since you know that they are always identical. This also splits up the function to validate the anon_vma re-use, and adds a lot of commentary about the possible races. Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Borislav Petkov <bp@alien8.de> [ "That didn't fix it" ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-10 21:36:19 +04:00
if (anon_vma && list_is_singular(&old->anon_vma_chain))
return anon_vma;
}
return NULL;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* find_mergeable_anon_vma is used by anon_vma_prepare, to check
* neighbouring vmas for a suitable anon_vma, before it goes off
* to allocate a new anon_vma. It checks because a repetitive
* sequence of mprotects and faults may otherwise lead to distinct
* anon_vmas being allocated, preventing vma merge in subsequent
* mprotect.
*/
struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
{
mm/mmap.c: get rid of odd jump labels in find_mergeable_anon_vma() The jump labels try_prev and none are not really needed in find_mergeable_anon_vma(), eliminate them to improve readability. Link: http://lkml.kernel.org/r/1574079844-17493-1-git-send-email-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31 09:14:51 +03:00
struct anon_vma *anon_vma = NULL;
/* Try next first. */
if (vma->vm_next) {
anon_vma = reusable_anon_vma(vma->vm_next, vma, vma->vm_next);
if (anon_vma)
return anon_vma;
}
/* Try prev next. */
if (vma->vm_prev)
anon_vma = reusable_anon_vma(vma->vm_prev, vma->vm_prev, vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
mm/mmap.c: get rid of odd jump labels in find_mergeable_anon_vma() The jump labels try_prev and none are not really needed in find_mergeable_anon_vma(), eliminate them to improve readability. Link: http://lkml.kernel.org/r/1574079844-17493-1-git-send-email-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31 09:14:51 +03:00
* We might reach here with anon_vma == NULL if we can't find
* any reusable anon_vma.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
* There's no absolute need to look only at touching neighbours:
* we could search further afield for "compatible" anon_vmas.
* But it would probably just be a waste of time searching,
* or lead to too many vmas hanging off the same anon_vma.
* We're trying to allow mprotect remerging later on,
* not trying to minimize memory used for anon_vmas.
*/
mm/mmap.c: get rid of odd jump labels in find_mergeable_anon_vma() The jump labels try_prev and none are not really needed in find_mergeable_anon_vma(), eliminate them to improve readability. Link: http://lkml.kernel.org/r/1574079844-17493-1-git-send-email-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31 09:14:51 +03:00
return anon_vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
security: trim security.h Trim security.h Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Morris <jmorris@namei.org>
2012-02-13 07:58:52 +04:00
/*
* If a hint addr is less than mmap_min_addr change hint to be as
* low as possible but still greater than mmap_min_addr
*/
static inline unsigned long round_hint_to_min(unsigned long hint)
{
hint &= PAGE_MASK;
if (((void *)hint != NULL) &&
(hint < mmap_min_addr))
return PAGE_ALIGN(mmap_min_addr);
return hint;
}
mm/mmap.c: add mlock_future_check() helper Both do_brk and do_mmap_pgoff verify that we are actually capable of locking future pages if the corresponding VM_LOCKED flags are used. Encapsulate this logic into a single mlock_future_check() helper function. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-22 03:49:15 +04:00
static inline int mlock_future_check(struct mm_struct *mm,
unsigned long flags,
unsigned long len)
{
unsigned long locked, lock_limit;
/* mlock MCL_FUTURE? */
if (flags & VM_LOCKED) {
locked = len >> PAGE_SHIFT;
locked += mm->locked_vm;
lock_limit = rlimit(RLIMIT_MEMLOCK);
lock_limit >>= PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
return -EAGAIN;
}
return 0;
}
mmap: introduce sane default mmap limits The internal VM "mmap()" interfaces are based on the mmap target doing everything using page indexes rather than byte offsets, because traditionally (ie 32-bit) we had the situation that the byte offset didn't fit in a register. So while the mmap virtual address was limited by the word size of the architecture, the backing store was not. So we're basically passing "pgoff" around as a page index, in order to be able to describe backing store locations that are much bigger than the word size (think files larger than 4GB etc). But while this all makes a ton of sense conceptually, we've been dogged by various drivers that don't really understand this, and internally work with byte offsets, and then try to work with the page index by turning it into a byte offset with "pgoff << PAGE_SHIFT". Which obviously can overflow. Adding the size of the mapping to it to get the byte offset of the end of the backing store just exacerbates the problem, and if you then use this overflow-prone value to check various limits of your device driver mmap capability, you're just setting yourself up for problems. The correct thing for drivers to do is to do their limit math in page indices, the way the interface is designed. Because the generic mmap code _does_ test that the index doesn't overflow, since that's what the mmap code really cares about. HOWEVER. Finding and fixing various random drivers is a sisyphean task, so let's just see if we can just make the core mmap() code do the limiting for us. Realistically, the only "big" backing stores we need to care about are regular files and block devices, both of which are known to do this properly, and which have nice well-defined limits for how much data they can access. So let's special-case just those two known cases, and then limit other random mmap users to a backing store that still fits in "unsigned long". Realistically, that's not much of a limit at all on 64-bit, and on 32-bit architectures the only worry might be the GPU drivers, which can have big physical address spaces. To make it possible for drivers like that to say that they are 64-bit clean, this patch does repurpose the "FMODE_UNSIGNED_OFFSET" bit in the file flags to allow drivers to mark their file descriptors as safe in the full 64-bit mmap address space. [ The timing for doing this is less than optimal, and this should really go in a merge window. But realistically, this needs wide testing more than it needs anything else, and being main-line is the only way to do that. So the earlier the better, even if it's outside the proper development cycle - Linus ] Cc: Kees Cook <keescook@chromium.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Willy Tarreau <w@1wt.eu> Cc: Dave Airlie <airlied@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-11 19:52:01 +03:00
static inline u64 file_mmap_size_max(struct file *file, struct inode *inode)
{
if (S_ISREG(inode->i_mode))
mmap: relax file size limit for regular files Commit be83bbf80682 ("mmap: introduce sane default mmap limits") was introduced to catch problems in various ad-hoc character device drivers doing mmap and getting the size limits wrong. In the process, it used "known good" limits for the normal cases of mapping regular files and block device drivers. It turns out that the "s_maxbytes" limit was less "known good" than I thought. In particular, /proc doesn't set it, but exposes one regular file to mmap: /proc/vmcore. As a result, that file got limited to the default MAX_INT s_maxbytes value. This went unnoticed for a while, because apparently the only thing that needs it is the s390 kernel zfcpdump, but there might be other tools that use this too. Vasily suggested just changing s_maxbytes for all of /proc, which isn't wrong, but makes me nervous at this stage. So instead, just make the new mmap limit always be MAX_LFS_FILESIZE for regular files, which won't affect anything else. It wasn't the regular file case I was worried about. I'd really prefer for maxsize to have been per-inode, but that is not how things are today. Fixes: be83bbf80682 ("mmap: introduce sane default mmap limits") Reported-by: Vasily Gorbik <gor@linux.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-19 19:29:11 +03:00
return MAX_LFS_FILESIZE;
mmap: introduce sane default mmap limits The internal VM "mmap()" interfaces are based on the mmap target doing everything using page indexes rather than byte offsets, because traditionally (ie 32-bit) we had the situation that the byte offset didn't fit in a register. So while the mmap virtual address was limited by the word size of the architecture, the backing store was not. So we're basically passing "pgoff" around as a page index, in order to be able to describe backing store locations that are much bigger than the word size (think files larger than 4GB etc). But while this all makes a ton of sense conceptually, we've been dogged by various drivers that don't really understand this, and internally work with byte offsets, and then try to work with the page index by turning it into a byte offset with "pgoff << PAGE_SHIFT". Which obviously can overflow. Adding the size of the mapping to it to get the byte offset of the end of the backing store just exacerbates the problem, and if you then use this overflow-prone value to check various limits of your device driver mmap capability, you're just setting yourself up for problems. The correct thing for drivers to do is to do their limit math in page indices, the way the interface is designed. Because the generic mmap code _does_ test that the index doesn't overflow, since that's what the mmap code really cares about. HOWEVER. Finding and fixing various random drivers is a sisyphean task, so let's just see if we can just make the core mmap() code do the limiting for us. Realistically, the only "big" backing stores we need to care about are regular files and block devices, both of which are known to do this properly, and which have nice well-defined limits for how much data they can access. So let's special-case just those two known cases, and then limit other random mmap users to a backing store that still fits in "unsigned long". Realistically, that's not much of a limit at all on 64-bit, and on 32-bit architectures the only worry might be the GPU drivers, which can have big physical address spaces. To make it possible for drivers like that to say that they are 64-bit clean, this patch does repurpose the "FMODE_UNSIGNED_OFFSET" bit in the file flags to allow drivers to mark their file descriptors as safe in the full 64-bit mmap address space. [ The timing for doing this is less than optimal, and this should really go in a merge window. But realistically, this needs wide testing more than it needs anything else, and being main-line is the only way to do that. So the earlier the better, even if it's outside the proper development cycle - Linus ] Cc: Kees Cook <keescook@chromium.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Willy Tarreau <w@1wt.eu> Cc: Dave Airlie <airlied@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-11 19:52:01 +03:00
if (S_ISBLK(inode->i_mode))
return MAX_LFS_FILESIZE;
mm: mmap: increase sockets maximum memory size pgoff for 32bits The AF_XDP sockets umem mapping interface uses XDP_UMEM_PGOFF_FILL_RING and XDP_UMEM_PGOFF_COMPLETION_RING offsets. These offsets are established already and are part of the configuration interface. But for 32-bit systems, using AF_XDP socket configuration, these values are too large to pass the maximum allowed file size verification. The offsets can be tuned off, but instead of changing the existing interface, let's extend the max allowed file size for sockets. No one has been using this until this patch with 32 bits as without this fix af_xdp sockets can't be used at all, so it unblocks af_xdp socket usage for 32bit systems. All list of mmap cbs for sockets was verified for side effects and all of them contain dummy cb - sock_no_mmap() at this moment, except the following: xsk_mmap() - it's what this fix is needed for. tcp_mmap() - doesn't have obvious issues with pgoff - no any references on it. packet_mmap() - return -EINVAL if it's even set. Link: http://lkml.kernel.org/r/20190812124326.32146-1-ivan.khoronzhuk@linaro.org Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Björn Töpel <bjorn.topel@intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Magnus Karlsson <magnus.karlsson@intel.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24 01:39:28 +03:00
if (S_ISSOCK(inode->i_mode))
return MAX_LFS_FILESIZE;
mmap: introduce sane default mmap limits The internal VM "mmap()" interfaces are based on the mmap target doing everything using page indexes rather than byte offsets, because traditionally (ie 32-bit) we had the situation that the byte offset didn't fit in a register. So while the mmap virtual address was limited by the word size of the architecture, the backing store was not. So we're basically passing "pgoff" around as a page index, in order to be able to describe backing store locations that are much bigger than the word size (think files larger than 4GB etc). But while this all makes a ton of sense conceptually, we've been dogged by various drivers that don't really understand this, and internally work with byte offsets, and then try to work with the page index by turning it into a byte offset with "pgoff << PAGE_SHIFT". Which obviously can overflow. Adding the size of the mapping to it to get the byte offset of the end of the backing store just exacerbates the problem, and if you then use this overflow-prone value to check various limits of your device driver mmap capability, you're just setting yourself up for problems. The correct thing for drivers to do is to do their limit math in page indices, the way the interface is designed. Because the generic mmap code _does_ test that the index doesn't overflow, since that's what the mmap code really cares about. HOWEVER. Finding and fixing various random drivers is a sisyphean task, so let's just see if we can just make the core mmap() code do the limiting for us. Realistically, the only "big" backing stores we need to care about are regular files and block devices, both of which are known to do this properly, and which have nice well-defined limits for how much data they can access. So let's special-case just those two known cases, and then limit other random mmap users to a backing store that still fits in "unsigned long". Realistically, that's not much of a limit at all on 64-bit, and on 32-bit architectures the only worry might be the GPU drivers, which can have big physical address spaces. To make it possible for drivers like that to say that they are 64-bit clean, this patch does repurpose the "FMODE_UNSIGNED_OFFSET" bit in the file flags to allow drivers to mark their file descriptors as safe in the full 64-bit mmap address space. [ The timing for doing this is less than optimal, and this should really go in a merge window. But realistically, this needs wide testing more than it needs anything else, and being main-line is the only way to do that. So the earlier the better, even if it's outside the proper development cycle - Linus ] Cc: Kees Cook <keescook@chromium.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Willy Tarreau <w@1wt.eu> Cc: Dave Airlie <airlied@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-11 19:52:01 +03:00
/* Special "we do even unsigned file positions" case */
if (file->f_mode & FMODE_UNSIGNED_OFFSET)
return 0;
/* Yes, random drivers might want more. But I'm tired of buggy drivers */
return ULONG_MAX;
}
static inline bool file_mmap_ok(struct file *file, struct inode *inode,
unsigned long pgoff, unsigned long len)
{
u64 maxsize = file_mmap_size_max(file, inode);
if (maxsize && len > maxsize)
return false;
maxsize -= len;
if (pgoff > maxsize >> PAGE_SHIFT)
return false;
return true;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
mmap locking API: convert mmap_sem API comments Convert comments that reference old mmap_sem APIs to reference corresponding new mmap locking APIs instead. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-12-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:51 +03:00
* The caller must write-lock current->mm->mmap_lock.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff() Add the additional "vm_flags_t vm_flags" argument to do_mmap_pgoff(), rename it to do_mmap(), and re-introduce do_mmap_pgoff() as a simple wrapper on top of do_mmap(). Perhaps we should update the callers of do_mmap_pgoff() and kill it later. This way mpx_mmap() can simply call do_mmap(vm_flags => VM_MPX) and do not play with vm internals. After this change mmap_region() has a single user outside of mmap.c, arch/tile/mm/elf.c:arch_setup_additional_pages(). It would be nice to change arch/tile/ and unexport mmap_region(). [kirill@shutemov.name: fix build] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Tested-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Minchan Kim <minchan@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 01:39:29 +03:00
unsigned long do_mmap(struct file *file, unsigned long addr,
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
unsigned long len, unsigned long prot,
mm: remove unnecessary wrapper function do_mmap_pgoff() The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db7f82 ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:37 +03:00
unsigned long flags, unsigned long pgoff,
unsigned long *populate, struct list_head *uf)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
struct mm_struct *mm = current->mm;
mm: remove unnecessary wrapper function do_mmap_pgoff() The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db7f82 ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:37 +03:00
vm_flags_t vm_flags;
mm/core, x86/mm/pkeys: Add execute-only protection keys support Protection keys provide new page-based protection in hardware. But, they have an interesting attribute: they only affect data accesses and never affect instruction fetches. That means that if we set up some memory which is set as "access-disabled" via protection keys, we can still execute from it. This patch uses protection keys to set up mappings to do just that. If a user calls: mmap(..., PROT_EXEC); or mprotect(ptr, sz, PROT_EXEC); (note PROT_EXEC-only without PROT_READ/WRITE), the kernel will notice this, and set a special protection key on the memory. It also sets the appropriate bits in the Protection Keys User Rights (PKRU) register so that the memory becomes unreadable and unwritable. I haven't found any userspace that does this today. With this facility in place, we expect userspace to move to use it eventually. Userspace _could_ start doing this today. Any PROT_EXEC calls get converted to PROT_READ inside the kernel, and would transparently be upgraded to "true" PROT_EXEC with this code. IOW, userspace never has to do any PROT_EXEC runtime detection. This feature provides enhanced protection against leaking executable memory contents. This helps thwart attacks which are attempting to find ROP gadgets on the fly. But, the security provided by this approach is not comprehensive. The PKRU register which controls access permissions is a normal user register writable from unprivileged userspace. An attacker who can execute the 'wrpkru' instruction can easily disable the protection provided by this feature. The protection key that is used for execute-only support is permanently dedicated at compile time. This is fine for now because there is currently no API to set a protection key other than this one. Despite there being a constant PKRU value across the entire system, we do not set it unless this feature is in use in a process. That is to preserve the PKRU XSAVE 'init state', which can lead to faster context switches. PKRU *is* a user register and the kernel is modifying it. That means that code doing: pkru = rdpkru() pkru |= 0x100; mmap(..., PROT_EXEC); wrpkru(pkru); could lose the bits in PKRU that enforce execute-only permissions. To avoid this, we suggest avoiding ever calling mmap() or mprotect() when the PKRU value is expected to be unstable. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Gang <gang.chen.5i5j@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave@sr71.net> Cc: David Hildenbrand <dahi@linux.vnet.ibm.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Piotr Kwapulinski <kwapulinski.piotr@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Vladimir Murzin <vladimir.murzin@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: keescook@google.com Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210240.CB4BB5CA@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-13 00:02:40 +03:00
int pkey = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: make do_mmap_pgoff return populate as a size in bytes, not as a bool do_mmap_pgoff() rounds up the desired size to the next PAGE_SIZE multiple, however there was no equivalent code in mm_populate(), which caused issues. This could be fixed by introduced the same rounding in mm_populate(), however I think it's preferable to make do_mmap_pgoff() return populate as a size rather than as a boolean, so we don't have to duplicate the size rounding logic in mm_populate(). Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:47 +04:00
*populate = 0;
mm: introduce mm_populate() for populating new vmas When creating new mappings using the MAP_POPULATE / MAP_LOCKED flags (or with MCL_FUTURE in effect), we want to populate the pages within the newly created vmas. This may take a while as we may have to read pages from disk, so ideally we want to do this outside of the write-locked mmap_sem region. This change introduces mm_populate(), which is used to defer populating such mappings until after the mmap_sem write lock has been released. This is implemented as a generalization of the former do_mlock_pages(), which accomplished the same task but was using during mlock() / mlockall(). Signed-off-by: Michel Lespinasse <walken@google.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:37 +04:00
mm/mmap.c: optimization of do_mmap_pgoff function The simple check for zero length memory mapping may be performed earlier. So that in case of zero length memory mapping some unnecessary code is not executed at all. It does not make the code less readable and saves some CPU cycles. Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@gmail.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 02:58:39 +03:00
if (!len)
return -EINVAL;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* Does the application expect PROT_READ to imply PROT_EXEC?
*
* (the exception is when the underlying filesystem is noexec
* mounted, in which case we dont add PROT_EXEC.)
*/
if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
vfs: Commit to never having exectuables on proc and sysfs. Today proc and sysfs do not contain any executable files. Several applications today mount proc or sysfs without noexec and nosuid and then depend on there being no exectuables files on proc or sysfs. Having any executable files show on proc or sysfs would cause a user space visible regression, and most likely security problems. Therefore commit to never allowing executables on proc and sysfs by adding a new flag to mark them as filesystems without executables and enforce that flag. Test the flag where MNT_NOEXEC is tested today, so that the only user visible effect will be that exectuables will be treated as if the execute bit is cleared. The filesystems proc and sysfs do not currently incoporate any executable files so this does not result in any user visible effects. This makes it unnecessary to vet changes to proc and sysfs tightly for adding exectuable files or changes to chattr that would modify existing files, as no matter what the individual file say they will not be treated as exectuable files by the vfs. Not having to vet changes to closely is important as without this we are only one proc_create call (or another goof up in the implementation of notify_change) from having problematic executables on proc. Those mistakes are all too easy to make and would create a situation where there are security issues or the assumptions of some program having to be broken (and cause userspace regressions). Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2015-06-29 22:42:03 +03:00
if (!(file && path_noexec(&file->f_path)))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
prot |= PROT_EXEC;
mm: introduce MAP_FIXED_NOREPLACE Patch series "mm: introduce MAP_FIXED_NOREPLACE", v2. This has started as a follow up discussion [3][4] resulting in the runtime failure caused by hardening patch [5] which removes MAP_FIXED from the elf loader because MAP_FIXED is inherently dangerous as it might silently clobber an existing underlying mapping (e.g. stack). The reason for the failure is that some architectures enforce an alignment for the given address hint without MAP_FIXED used (e.g. for shared or file backed mappings). One way around this would be excluding those archs which do alignment tricks from the hardening [6]. The patch is really trivial but it has been objected, rightfully so, that this screams for a more generic solution. We basically want a non-destructive MAP_FIXED. The first patch introduced MAP_FIXED_NOREPLACE which enforces the given address but unlike MAP_FIXED it fails with EEXIST if the given range conflicts with an existing one. The flag is introduced as a completely new one rather than a MAP_FIXED extension because of the backward compatibility. We really want a never-clobber semantic even on older kernels which do not recognize the flag. Unfortunately mmap sucks wrt flags evaluation because we do not EINVAL on unknown flags. On those kernels we would simply use the traditional hint based semantic so the caller can still get a different address (which sucks) but at least not silently corrupt an existing mapping. I do not see a good way around that. Except we won't export expose the new semantic to the userspace at all. It seems there are users who would like to have something like that. Jemalloc has been mentioned by Michael Ellerman [7] Florian Weimer has mentioned the following: : glibc ld.so currently maps DSOs without hints. This means that the kernel : will map right next to each other, and the offsets between them a completely : predictable. We would like to change that and supply a random address in a : window of the address space. If there is a conflict, we do not want the : kernel to pick a non-random address. Instead, we would try again with a : random address. John Hubbard has mentioned CUDA example : a) Searches /proc/<pid>/maps for a "suitable" region of available : VA space. "Suitable" generally means it has to have a base address : within a certain limited range (a particular device model might : have odd limitations, for example), it has to be large enough, and : alignment has to be large enough (again, various devices may have : constraints that lead us to do this). : : This is of course subject to races with other threads in the process. : : Let's say it finds a region starting at va. : : b) Next it does: : p = mmap(va, ...) : : *without* setting MAP_FIXED, of course (so va is just a hint), to : attempt to safely reserve that region. If p != va, then in most cases, : this is a failure (almost certainly due to another thread getting a : mapping from that region before we did), and so this layer now has to : call munmap(), before returning a "failure: retry" to upper layers. : : IMPROVEMENT: --> if instead, we could call this: : : p = mmap(va, ... MAP_FIXED_NOREPLACE ...) : : , then we could skip the munmap() call upon failure. This : is a small thing, but it is useful here. (Thanks to Piotr : Jaroszynski and Mark Hairgrove for helping me get that detail : exactly right, btw.) : : c) After that, CUDA suballocates from p, via: : : q = mmap(sub_region_start, ... MAP_FIXED ...) : : Interestingly enough, "freeing" is also done via MAP_FIXED, and : setting PROT_NONE to the subregion. Anyway, I just included (c) for : general interest. Atomic address range probing in the multithreaded programs in general sounds like an interesting thing to me. The second patch simply replaces MAP_FIXED use in elf loader by MAP_FIXED_NOREPLACE. I believe other places which rely on MAP_FIXED should follow. Actually real MAP_FIXED usages should be docummented properly and they should be more of an exception. [1] http://lkml.kernel.org/r/20171116101900.13621-1-mhocko@kernel.org [2] http://lkml.kernel.org/r/20171129144219.22867-1-mhocko@kernel.org [3] http://lkml.kernel.org/r/20171107162217.382cd754@canb.auug.org.au [4] http://lkml.kernel.org/r/1510048229.12079.7.camel@abdul.in.ibm.com [5] http://lkml.kernel.org/r/20171023082608.6167-1-mhocko@kernel.org [6] http://lkml.kernel.org/r/20171113094203.aofz2e7kueitk55y@dhcp22.suse.cz [7] http://lkml.kernel.org/r/87efp1w7vy.fsf@concordia.ellerman.id.au This patch (of 2): MAP_FIXED is used quite often to enforce mapping at the particular range. The main problem of this flag is, however, that it is inherently dangerous because it unmaps existing mappings covered by the requested range. This can cause silent memory corruptions. Some of them even with serious security implications. While the current semantic might be really desiderable in many cases there are others which would want to enforce the given range but rather see a failure than a silent memory corruption on a clashing range. Please note that there is no guarantee that a given range is obeyed by the mmap even when it is free - e.g. arch specific code is allowed to apply an alignment. Introduce a new MAP_FIXED_NOREPLACE flag for mmap to achieve this behavior. It has the same semantic as MAP_FIXED wrt. the given address request with a single exception that it fails with EEXIST if the requested address is already covered by an existing mapping. We still do rely on get_unmaped_area to handle all the arch specific MAP_FIXED treatment and check for a conflicting vma after it returns. The flag is introduced as a completely new one rather than a MAP_FIXED extension because of the backward compatibility. We really want a never-clobber semantic even on older kernels which do not recognize the flag. Unfortunately mmap sucks wrt. flags evaluation because we do not EINVAL on unknown flags. On those kernels we would simply use the traditional hint based semantic so the caller can still get a different address (which sucks) but at least not silently corrupt an existing mapping. I do not see a good way around that. [mpe@ellerman.id.au: fix whitespace] [fail on clashing range with EEXIST as per Florian Weimer] [set MAP_FIXED before round_hint_to_min as per Khalid Aziz] Link: http://lkml.kernel.org/r/20171213092550.2774-2-mhocko@kernel.org Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Russell King - ARM Linux <linux@armlinux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Joel Stanley <joel@jms.id.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Jason Evans <jasone@google.com> Cc: David Goldblatt <davidtgoldblatt@gmail.com> Cc: Edward Tomasz Napierała <trasz@FreeBSD.org> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 02:35:57 +03:00
/* force arch specific MAP_FIXED handling in get_unmapped_area */
if (flags & MAP_FIXED_NOREPLACE)
flags |= MAP_FIXED;
Security: round mmap hint address above mmap_min_addr If mmap_min_addr is set and a process attempts to mmap (not fixed) with a non-null hint address less than mmap_min_addr the mapping will fail the security checks. Since this is just a hint address this patch will round such a hint address above mmap_min_addr. gcj was found to try to be very frugal with vm usage and give hint addresses in the 8k-32k range. Without this patch all such programs failed and with the patch they happily get a higher address. This patch is wrappad in CONFIG_SECURITY since mmap_min_addr doesn't exist without it and there would be no security check possible no matter what. So we should not bother compiling in this rounding if it is just a waste of time. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2007-11-27 02:47:40 +03:00
if (!(flags & MAP_FIXED))
addr = round_hint_to_min(addr);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Careful about overflows.. */
len = PAGE_ALIGN(len);
Take arch_mmap_check() into get_unmapped_area() Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-03 23:23:11 +03:00
if (!len)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -ENOMEM;
/* offset overflow? */
if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
return -EOVERFLOW;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Too many mappings? */
if (mm->map_count > sysctl_max_map_count)
return -ENOMEM;
/* Obtain the address to map to. we verify (or select) it and ensure
* that it represents a valid section of the address space.
*/
addr = get_unmapped_area(file, addr, len, pgoff, flags);
mm/mmap.c: use IS_ERR_VALUE to check return value of get_unmapped_area get_unmapped_area() returns an address or -errno on failure. Historically we have checked for the failure by offset_in_page() which is correct but quite hard to read. Newer code started using IS_ERR_VALUE which is much easier to read. Convert remaining users of offset_in_page as well. [mhocko@suse.com: rewrite changelog] [mhocko@kernel.org: fix mremap.c and uprobes.c sites also] Link: http://lkml.kernel.org/r/20191012102512.28051-1-pugaowei@gmail.com Signed-off-by: Gaowei Pu <pugaowei@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Rik van Riel <riel@surriel.com> Cc: Qian Cai <cai@lca.pw> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 04:51:03 +03:00
if (IS_ERR_VALUE(addr))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return addr;
mm: introduce MAP_FIXED_NOREPLACE Patch series "mm: introduce MAP_FIXED_NOREPLACE", v2. This has started as a follow up discussion [3][4] resulting in the runtime failure caused by hardening patch [5] which removes MAP_FIXED from the elf loader because MAP_FIXED is inherently dangerous as it might silently clobber an existing underlying mapping (e.g. stack). The reason for the failure is that some architectures enforce an alignment for the given address hint without MAP_FIXED used (e.g. for shared or file backed mappings). One way around this would be excluding those archs which do alignment tricks from the hardening [6]. The patch is really trivial but it has been objected, rightfully so, that this screams for a more generic solution. We basically want a non-destructive MAP_FIXED. The first patch introduced MAP_FIXED_NOREPLACE which enforces the given address but unlike MAP_FIXED it fails with EEXIST if the given range conflicts with an existing one. The flag is introduced as a completely new one rather than a MAP_FIXED extension because of the backward compatibility. We really want a never-clobber semantic even on older kernels which do not recognize the flag. Unfortunately mmap sucks wrt flags evaluation because we do not EINVAL on unknown flags. On those kernels we would simply use the traditional hint based semantic so the caller can still get a different address (which sucks) but at least not silently corrupt an existing mapping. I do not see a good way around that. Except we won't export expose the new semantic to the userspace at all. It seems there are users who would like to have something like that. Jemalloc has been mentioned by Michael Ellerman [7] Florian Weimer has mentioned the following: : glibc ld.so currently maps DSOs without hints. This means that the kernel : will map right next to each other, and the offsets between them a completely : predictable. We would like to change that and supply a random address in a : window of the address space. If there is a conflict, we do not want the : kernel to pick a non-random address. Instead, we would try again with a : random address. John Hubbard has mentioned CUDA example : a) Searches /proc/<pid>/maps for a "suitable" region of available : VA space. "Suitable" generally means it has to have a base address : within a certain limited range (a particular device model might : have odd limitations, for example), it has to be large enough, and : alignment has to be large enough (again, various devices may have : constraints that lead us to do this). : : This is of course subject to races with other threads in the process. : : Let's say it finds a region starting at va. : : b) Next it does: : p = mmap(va, ...) : : *without* setting MAP_FIXED, of course (so va is just a hint), to : attempt to safely reserve that region. If p != va, then in most cases, : this is a failure (almost certainly due to another thread getting a : mapping from that region before we did), and so this layer now has to : call munmap(), before returning a "failure: retry" to upper layers. : : IMPROVEMENT: --> if instead, we could call this: : : p = mmap(va, ... MAP_FIXED_NOREPLACE ...) : : , then we could skip the munmap() call upon failure. This : is a small thing, but it is useful here. (Thanks to Piotr : Jaroszynski and Mark Hairgrove for helping me get that detail : exactly right, btw.) : : c) After that, CUDA suballocates from p, via: : : q = mmap(sub_region_start, ... MAP_FIXED ...) : : Interestingly enough, "freeing" is also done via MAP_FIXED, and : setting PROT_NONE to the subregion. Anyway, I just included (c) for : general interest. Atomic address range probing in the multithreaded programs in general sounds like an interesting thing to me. The second patch simply replaces MAP_FIXED use in elf loader by MAP_FIXED_NOREPLACE. I believe other places which rely on MAP_FIXED should follow. Actually real MAP_FIXED usages should be docummented properly and they should be more of an exception. [1] http://lkml.kernel.org/r/20171116101900.13621-1-mhocko@kernel.org [2] http://lkml.kernel.org/r/20171129144219.22867-1-mhocko@kernel.org [3] http://lkml.kernel.org/r/20171107162217.382cd754@canb.auug.org.au [4] http://lkml.kernel.org/r/1510048229.12079.7.camel@abdul.in.ibm.com [5] http://lkml.kernel.org/r/20171023082608.6167-1-mhocko@kernel.org [6] http://lkml.kernel.org/r/20171113094203.aofz2e7kueitk55y@dhcp22.suse.cz [7] http://lkml.kernel.org/r/87efp1w7vy.fsf@concordia.ellerman.id.au This patch (of 2): MAP_FIXED is used quite often to enforce mapping at the particular range. The main problem of this flag is, however, that it is inherently dangerous because it unmaps existing mappings covered by the requested range. This can cause silent memory corruptions. Some of them even with serious security implications. While the current semantic might be really desiderable in many cases there are others which would want to enforce the given range but rather see a failure than a silent memory corruption on a clashing range. Please note that there is no guarantee that a given range is obeyed by the mmap even when it is free - e.g. arch specific code is allowed to apply an alignment. Introduce a new MAP_FIXED_NOREPLACE flag for mmap to achieve this behavior. It has the same semantic as MAP_FIXED wrt. the given address request with a single exception that it fails with EEXIST if the requested address is already covered by an existing mapping. We still do rely on get_unmaped_area to handle all the arch specific MAP_FIXED treatment and check for a conflicting vma after it returns. The flag is introduced as a completely new one rather than a MAP_FIXED extension because of the backward compatibility. We really want a never-clobber semantic even on older kernels which do not recognize the flag. Unfortunately mmap sucks wrt. flags evaluation because we do not EINVAL on unknown flags. On those kernels we would simply use the traditional hint based semantic so the caller can still get a different address (which sucks) but at least not silently corrupt an existing mapping. I do not see a good way around that. [mpe@ellerman.id.au: fix whitespace] [fail on clashing range with EEXIST as per Florian Weimer] [set MAP_FIXED before round_hint_to_min as per Khalid Aziz] Link: http://lkml.kernel.org/r/20171213092550.2774-2-mhocko@kernel.org Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Russell King - ARM Linux <linux@armlinux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Joel Stanley <joel@jms.id.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Jason Evans <jasone@google.com> Cc: David Goldblatt <davidtgoldblatt@gmail.com> Cc: Edward Tomasz Napierała <trasz@FreeBSD.org> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 02:35:57 +03:00
if (flags & MAP_FIXED_NOREPLACE) {
struct vm_area_struct *vma = find_vma(mm, addr);
mm/mmap.c: don't clobber partially overlapping VMA with MAP_FIXED_NOREPLACE Daniel Micay reports that attempting to use MAP_FIXED_NOREPLACE in an application causes that application to randomly crash. The existing check for handling MAP_FIXED_NOREPLACE looks up the first VMA that either overlaps or follows the requested region, and then bails out if that VMA overlaps *the start* of the requested region. It does not bail out if the VMA only overlaps another part of the requested region. Fix it by checking that the found VMA only starts at or after the end of the requested region, in which case there is no overlap. Test case: user@debian:~$ cat mmap_fixed_simple.c #include <sys/mman.h> #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #ifndef MAP_FIXED_NOREPLACE #define MAP_FIXED_NOREPLACE 0x100000 #endif int main(void) { char *p; errno = 0; p = mmap((void*)0x10001000, 0x4000, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED_NOREPLACE, -1, 0); printf("p1=%p err=%m\n", p); errno = 0; p = mmap((void*)0x10000000, 0x2000, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED_NOREPLACE, -1, 0); printf("p2=%p err=%m\n", p); char cmd[100]; sprintf(cmd, "cat /proc/%d/maps", getpid()); system(cmd); return 0; } user@debian:~$ gcc -o mmap_fixed_simple mmap_fixed_simple.c user@debian:~$ ./mmap_fixed_simple p1=0x10001000 err=Success p2=0x10000000 err=Success 10000000-10002000 r--p 00000000 00:00 0 10002000-10005000 ---p 00000000 00:00 0 564a9a06f000-564a9a070000 r-xp 00000000 fe:01 264004 /home/user/mmap_fixed_simple 564a9a26f000-564a9a270000 r--p 00000000 fe:01 264004 /home/user/mmap_fixed_simple 564a9a270000-564a9a271000 rw-p 00001000 fe:01 264004 /home/user/mmap_fixed_simple 564a9a54a000-564a9a56b000 rw-p 00000000 00:00 0 [heap] 7f8eba447000-7f8eba5dc000 r-xp 00000000 fe:01 405885 /lib/x86_64-linux-gnu/libc-2.24.so 7f8eba5dc000-7f8eba7dc000 ---p 00195000 fe:01 405885 /lib/x86_64-linux-gnu/libc-2.24.so 7f8eba7dc000-7f8eba7e0000 r--p 00195000 fe:01 405885 /lib/x86_64-linux-gnu/libc-2.24.so 7f8eba7e0000-7f8eba7e2000 rw-p 00199000 fe:01 405885 /lib/x86_64-linux-gnu/libc-2.24.so 7f8eba7e2000-7f8eba7e6000 rw-p 00000000 00:00 0 7f8eba7e6000-7f8eba809000 r-xp 00000000 fe:01 405876 /lib/x86_64-linux-gnu/ld-2.24.so 7f8eba9e9000-7f8eba9eb000 rw-p 00000000 00:00 0 7f8ebaa06000-7f8ebaa09000 rw-p 00000000 00:00 0 7f8ebaa09000-7f8ebaa0a000 r--p 00023000 fe:01 405876 /lib/x86_64-linux-gnu/ld-2.24.so 7f8ebaa0a000-7f8ebaa0b000 rw-p 00024000 fe:01 405876 /lib/x86_64-linux-gnu/ld-2.24.so 7f8ebaa0b000-7f8ebaa0c000 rw-p 00000000 00:00 0 7ffcc99fa000-7ffcc9a1b000 rw-p 00000000 00:00 0 [stack] 7ffcc9b44000-7ffcc9b47000 r--p 00000000 00:00 0 [vvar] 7ffcc9b47000-7ffcc9b49000 r-xp 00000000 00:00 0 [vdso] ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall] user@debian:~$ uname -a Linux debian 4.19.0-rc6+ #181 SMP Wed Oct 3 23:43:42 CEST 2018 x86_64 GNU/Linux user@debian:~$ As you can see, the first page of the mapping at 0x10001000 was clobbered. Link: http://lkml.kernel.org/r/20181010152736.99475-1-jannh@google.com Fixes: a4ff8e8620d3 ("mm: introduce MAP_FIXED_NOREPLACE") Signed-off-by: Jann Horn <jannh@google.com> Reported-by: Daniel Micay <danielmicay@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-13 07:34:32 +03:00
if (vma && vma->vm_start < addr + len)
mm: introduce MAP_FIXED_NOREPLACE Patch series "mm: introduce MAP_FIXED_NOREPLACE", v2. This has started as a follow up discussion [3][4] resulting in the runtime failure caused by hardening patch [5] which removes MAP_FIXED from the elf loader because MAP_FIXED is inherently dangerous as it might silently clobber an existing underlying mapping (e.g. stack). The reason for the failure is that some architectures enforce an alignment for the given address hint without MAP_FIXED used (e.g. for shared or file backed mappings). One way around this would be excluding those archs which do alignment tricks from the hardening [6]. The patch is really trivial but it has been objected, rightfully so, that this screams for a more generic solution. We basically want a non-destructive MAP_FIXED. The first patch introduced MAP_FIXED_NOREPLACE which enforces the given address but unlike MAP_FIXED it fails with EEXIST if the given range conflicts with an existing one. The flag is introduced as a completely new one rather than a MAP_FIXED extension because of the backward compatibility. We really want a never-clobber semantic even on older kernels which do not recognize the flag. Unfortunately mmap sucks wrt flags evaluation because we do not EINVAL on unknown flags. On those kernels we would simply use the traditional hint based semantic so the caller can still get a different address (which sucks) but at least not silently corrupt an existing mapping. I do not see a good way around that. Except we won't export expose the new semantic to the userspace at all. It seems there are users who would like to have something like that. Jemalloc has been mentioned by Michael Ellerman [7] Florian Weimer has mentioned the following: : glibc ld.so currently maps DSOs without hints. This means that the kernel : will map right next to each other, and the offsets between them a completely : predictable. We would like to change that and supply a random address in a : window of the address space. If there is a conflict, we do not want the : kernel to pick a non-random address. Instead, we would try again with a : random address. John Hubbard has mentioned CUDA example : a) Searches /proc/<pid>/maps for a "suitable" region of available : VA space. "Suitable" generally means it has to have a base address : within a certain limited range (a particular device model might : have odd limitations, for example), it has to be large enough, and : alignment has to be large enough (again, various devices may have : constraints that lead us to do this). : : This is of course subject to races with other threads in the process. : : Let's say it finds a region starting at va. : : b) Next it does: : p = mmap(va, ...) : : *without* setting MAP_FIXED, of course (so va is just a hint), to : attempt to safely reserve that region. If p != va, then in most cases, : this is a failure (almost certainly due to another thread getting a : mapping from that region before we did), and so this layer now has to : call munmap(), before returning a "failure: retry" to upper layers. : : IMPROVEMENT: --> if instead, we could call this: : : p = mmap(va, ... MAP_FIXED_NOREPLACE ...) : : , then we could skip the munmap() call upon failure. This : is a small thing, but it is useful here. (Thanks to Piotr : Jaroszynski and Mark Hairgrove for helping me get that detail : exactly right, btw.) : : c) After that, CUDA suballocates from p, via: : : q = mmap(sub_region_start, ... MAP_FIXED ...) : : Interestingly enough, "freeing" is also done via MAP_FIXED, and : setting PROT_NONE to the subregion. Anyway, I just included (c) for : general interest. Atomic address range probing in the multithreaded programs in general sounds like an interesting thing to me. The second patch simply replaces MAP_FIXED use in elf loader by MAP_FIXED_NOREPLACE. I believe other places which rely on MAP_FIXED should follow. Actually real MAP_FIXED usages should be docummented properly and they should be more of an exception. [1] http://lkml.kernel.org/r/20171116101900.13621-1-mhocko@kernel.org [2] http://lkml.kernel.org/r/20171129144219.22867-1-mhocko@kernel.org [3] http://lkml.kernel.org/r/20171107162217.382cd754@canb.auug.org.au [4] http://lkml.kernel.org/r/1510048229.12079.7.camel@abdul.in.ibm.com [5] http://lkml.kernel.org/r/20171023082608.6167-1-mhocko@kernel.org [6] http://lkml.kernel.org/r/20171113094203.aofz2e7kueitk55y@dhcp22.suse.cz [7] http://lkml.kernel.org/r/87efp1w7vy.fsf@concordia.ellerman.id.au This patch (of 2): MAP_FIXED is used quite often to enforce mapping at the particular range. The main problem of this flag is, however, that it is inherently dangerous because it unmaps existing mappings covered by the requested range. This can cause silent memory corruptions. Some of them even with serious security implications. While the current semantic might be really desiderable in many cases there are others which would want to enforce the given range but rather see a failure than a silent memory corruption on a clashing range. Please note that there is no guarantee that a given range is obeyed by the mmap even when it is free - e.g. arch specific code is allowed to apply an alignment. Introduce a new MAP_FIXED_NOREPLACE flag for mmap to achieve this behavior. It has the same semantic as MAP_FIXED wrt. the given address request with a single exception that it fails with EEXIST if the requested address is already covered by an existing mapping. We still do rely on get_unmaped_area to handle all the arch specific MAP_FIXED treatment and check for a conflicting vma after it returns. The flag is introduced as a completely new one rather than a MAP_FIXED extension because of the backward compatibility. We really want a never-clobber semantic even on older kernels which do not recognize the flag. Unfortunately mmap sucks wrt. flags evaluation because we do not EINVAL on unknown flags. On those kernels we would simply use the traditional hint based semantic so the caller can still get a different address (which sucks) but at least not silently corrupt an existing mapping. I do not see a good way around that. [mpe@ellerman.id.au: fix whitespace] [fail on clashing range with EEXIST as per Florian Weimer] [set MAP_FIXED before round_hint_to_min as per Khalid Aziz] Link: http://lkml.kernel.org/r/20171213092550.2774-2-mhocko@kernel.org Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Russell King - ARM Linux <linux@armlinux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Joel Stanley <joel@jms.id.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Jason Evans <jasone@google.com> Cc: David Goldblatt <davidtgoldblatt@gmail.com> Cc: Edward Tomasz Napierała <trasz@FreeBSD.org> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 02:35:57 +03:00
return -EEXIST;
}
mm/core, x86/mm/pkeys: Add execute-only protection keys support Protection keys provide new page-based protection in hardware. But, they have an interesting attribute: they only affect data accesses and never affect instruction fetches. That means that if we set up some memory which is set as "access-disabled" via protection keys, we can still execute from it. This patch uses protection keys to set up mappings to do just that. If a user calls: mmap(..., PROT_EXEC); or mprotect(ptr, sz, PROT_EXEC); (note PROT_EXEC-only without PROT_READ/WRITE), the kernel will notice this, and set a special protection key on the memory. It also sets the appropriate bits in the Protection Keys User Rights (PKRU) register so that the memory becomes unreadable and unwritable. I haven't found any userspace that does this today. With this facility in place, we expect userspace to move to use it eventually. Userspace _could_ start doing this today. Any PROT_EXEC calls get converted to PROT_READ inside the kernel, and would transparently be upgraded to "true" PROT_EXEC with this code. IOW, userspace never has to do any PROT_EXEC runtime detection. This feature provides enhanced protection against leaking executable memory contents. This helps thwart attacks which are attempting to find ROP gadgets on the fly. But, the security provided by this approach is not comprehensive. The PKRU register which controls access permissions is a normal user register writable from unprivileged userspace. An attacker who can execute the 'wrpkru' instruction can easily disable the protection provided by this feature. The protection key that is used for execute-only support is permanently dedicated at compile time. This is fine for now because there is currently no API to set a protection key other than this one. Despite there being a constant PKRU value across the entire system, we do not set it unless this feature is in use in a process. That is to preserve the PKRU XSAVE 'init state', which can lead to faster context switches. PKRU *is* a user register and the kernel is modifying it. That means that code doing: pkru = rdpkru() pkru |= 0x100; mmap(..., PROT_EXEC); wrpkru(pkru); could lose the bits in PKRU that enforce execute-only permissions. To avoid this, we suggest avoiding ever calling mmap() or mprotect() when the PKRU value is expected to be unstable. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Gang <gang.chen.5i5j@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave@sr71.net> Cc: David Hildenbrand <dahi@linux.vnet.ibm.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Piotr Kwapulinski <kwapulinski.piotr@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Vladimir Murzin <vladimir.murzin@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: keescook@google.com Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210240.CB4BB5CA@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-13 00:02:40 +03:00
if (prot == PROT_EXEC) {
pkey = execute_only_pkey(mm);
if (pkey < 0)
pkey = 0;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Do simple checking here so the lower-level routines won't have
* to. we assume access permissions have been handled by the open
* of the memory object, so we don't do any here.
*/
mm: remove unnecessary wrapper function do_mmap_pgoff() The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db7f82 ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:37 +03:00
vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
mmap: remove unnecessary code If (flags & MAP_LOCKED) is true, it means vm_flags has already contained the bit VM_LOCKED which is set by calc_vm_flag_bits(). So there is no need to reset it again, just remove it. Signed-off-by: Huang Shijie <shijie8@gmail.com> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 04:03:36 +04:00
if (flags & MAP_LOCKED)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (!can_do_mlock())
return -EPERM;
mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:26:50 +04:00
mm/mmap.c: add mlock_future_check() helper Both do_brk and do_mmap_pgoff verify that we are actually capable of locking future pages if the corresponding VM_LOCKED flags are used. Encapsulate this logic into a single mlock_future_check() helper function. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-22 03:49:15 +04:00
if (mlock_future_check(mm, vm_flags, len))
return -EAGAIN;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (file) {
mm: do_mmap_pgoff: cleanup the usage of file_inode() Simple cleanup. Move "struct inode *inode" variable into "if (file)" block to simplify the code and avoid the unnecessary check. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Colin Cross <ccross@android.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:20:19 +04:00
struct inode *inode = file_inode(file);
mm: introduce MAP_SHARED_VALIDATE, a mechanism to safely define new mmap flags The mmap(2) syscall suffers from the ABI anti-pattern of not validating unknown flags. However, proposals like MAP_SYNC need a mechanism to define new behavior that is known to fail on older kernels without the support. Define a new MAP_SHARED_VALIDATE flag pattern that is guaranteed to fail on all legacy mmap implementations. It is worth noting that the original proposal was for a standalone MAP_VALIDATE flag. However, when that could not be supported by all archs Linus observed: I see why you *think* you want a bitmap. You think you want a bitmap because you want to make MAP_VALIDATE be part of MAP_SYNC etc, so that people can do ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_SYNC, fd, 0); and "know" that MAP_SYNC actually takes. And I'm saying that whole wish is bogus. You're fundamentally depending on special semantics, just make it explicit. It's already not portable, so don't try to make it so. Rename that MAP_VALIDATE as MAP_SHARED_VALIDATE, make it have a value of 0x3, and make people do ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED_VALIDATE | MAP_SYNC, fd, 0); and then the kernel side is easier too (none of that random garbage playing games with looking at the "MAP_VALIDATE bit", but just another case statement in that map type thing. Boom. Done. Similar to ->fallocate() we also want the ability to validate the support for new flags on a per ->mmap() 'struct file_operations' instance basis. Towards that end arrange for flags to be generically validated against a mmap_supported_flags exported by 'struct file_operations'. By default all existing flags are implicitly supported, but new flags require MAP_SHARED_VALIDATE and per-instance-opt-in. Cc: Jan Kara <jack@suse.cz> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Suggested-by: Christoph Hellwig <hch@lst.de> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-11-01 18:36:30 +03:00
unsigned long flags_mask;
mmap: introduce sane default mmap limits The internal VM "mmap()" interfaces are based on the mmap target doing everything using page indexes rather than byte offsets, because traditionally (ie 32-bit) we had the situation that the byte offset didn't fit in a register. So while the mmap virtual address was limited by the word size of the architecture, the backing store was not. So we're basically passing "pgoff" around as a page index, in order to be able to describe backing store locations that are much bigger than the word size (think files larger than 4GB etc). But while this all makes a ton of sense conceptually, we've been dogged by various drivers that don't really understand this, and internally work with byte offsets, and then try to work with the page index by turning it into a byte offset with "pgoff << PAGE_SHIFT". Which obviously can overflow. Adding the size of the mapping to it to get the byte offset of the end of the backing store just exacerbates the problem, and if you then use this overflow-prone value to check various limits of your device driver mmap capability, you're just setting yourself up for problems. The correct thing for drivers to do is to do their limit math in page indices, the way the interface is designed. Because the generic mmap code _does_ test that the index doesn't overflow, since that's what the mmap code really cares about. HOWEVER. Finding and fixing various random drivers is a sisyphean task, so let's just see if we can just make the core mmap() code do the limiting for us. Realistically, the only "big" backing stores we need to care about are regular files and block devices, both of which are known to do this properly, and which have nice well-defined limits for how much data they can access. So let's special-case just those two known cases, and then limit other random mmap users to a backing store that still fits in "unsigned long". Realistically, that's not much of a limit at all on 64-bit, and on 32-bit architectures the only worry might be the GPU drivers, which can have big physical address spaces. To make it possible for drivers like that to say that they are 64-bit clean, this patch does repurpose the "FMODE_UNSIGNED_OFFSET" bit in the file flags to allow drivers to mark their file descriptors as safe in the full 64-bit mmap address space. [ The timing for doing this is less than optimal, and this should really go in a merge window. But realistically, this needs wide testing more than it needs anything else, and being main-line is the only way to do that. So the earlier the better, even if it's outside the proper development cycle - Linus ] Cc: Kees Cook <keescook@chromium.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Willy Tarreau <w@1wt.eu> Cc: Dave Airlie <airlied@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-11 19:52:01 +03:00
if (!file_mmap_ok(file, inode, pgoff, len))
return -EOVERFLOW;
mm: introduce MAP_SHARED_VALIDATE, a mechanism to safely define new mmap flags The mmap(2) syscall suffers from the ABI anti-pattern of not validating unknown flags. However, proposals like MAP_SYNC need a mechanism to define new behavior that is known to fail on older kernels without the support. Define a new MAP_SHARED_VALIDATE flag pattern that is guaranteed to fail on all legacy mmap implementations. It is worth noting that the original proposal was for a standalone MAP_VALIDATE flag. However, when that could not be supported by all archs Linus observed: I see why you *think* you want a bitmap. You think you want a bitmap because you want to make MAP_VALIDATE be part of MAP_SYNC etc, so that people can do ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_SYNC, fd, 0); and "know" that MAP_SYNC actually takes. And I'm saying that whole wish is bogus. You're fundamentally depending on special semantics, just make it explicit. It's already not portable, so don't try to make it so. Rename that MAP_VALIDATE as MAP_SHARED_VALIDATE, make it have a value of 0x3, and make people do ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED_VALIDATE | MAP_SYNC, fd, 0); and then the kernel side is easier too (none of that random garbage playing games with looking at the "MAP_VALIDATE bit", but just another case statement in that map type thing. Boom. Done. Similar to ->fallocate() we also want the ability to validate the support for new flags on a per ->mmap() 'struct file_operations' instance basis. Towards that end arrange for flags to be generically validated against a mmap_supported_flags exported by 'struct file_operations'. By default all existing flags are implicitly supported, but new flags require MAP_SHARED_VALIDATE and per-instance-opt-in. Cc: Jan Kara <jack@suse.cz> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Suggested-by: Christoph Hellwig <hch@lst.de> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-11-01 18:36:30 +03:00
flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags;
mm: do_mmap_pgoff: cleanup the usage of file_inode() Simple cleanup. Move "struct inode *inode" variable into "if (file)" block to simplify the code and avoid the unnecessary check. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Colin Cross <ccross@android.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:20:19 +04:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
switch (flags & MAP_TYPE) {
case MAP_SHARED:
mm: introduce MAP_SHARED_VALIDATE, a mechanism to safely define new mmap flags The mmap(2) syscall suffers from the ABI anti-pattern of not validating unknown flags. However, proposals like MAP_SYNC need a mechanism to define new behavior that is known to fail on older kernels without the support. Define a new MAP_SHARED_VALIDATE flag pattern that is guaranteed to fail on all legacy mmap implementations. It is worth noting that the original proposal was for a standalone MAP_VALIDATE flag. However, when that could not be supported by all archs Linus observed: I see why you *think* you want a bitmap. You think you want a bitmap because you want to make MAP_VALIDATE be part of MAP_SYNC etc, so that people can do ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_SYNC, fd, 0); and "know" that MAP_SYNC actually takes. And I'm saying that whole wish is bogus. You're fundamentally depending on special semantics, just make it explicit. It's already not portable, so don't try to make it so. Rename that MAP_VALIDATE as MAP_SHARED_VALIDATE, make it have a value of 0x3, and make people do ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED_VALIDATE | MAP_SYNC, fd, 0); and then the kernel side is easier too (none of that random garbage playing games with looking at the "MAP_VALIDATE bit", but just another case statement in that map type thing. Boom. Done. Similar to ->fallocate() we also want the ability to validate the support for new flags on a per ->mmap() 'struct file_operations' instance basis. Towards that end arrange for flags to be generically validated against a mmap_supported_flags exported by 'struct file_operations'. By default all existing flags are implicitly supported, but new flags require MAP_SHARED_VALIDATE and per-instance-opt-in. Cc: Jan Kara <jack@suse.cz> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Suggested-by: Christoph Hellwig <hch@lst.de> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-11-01 18:36:30 +03:00
/*
* Force use of MAP_SHARED_VALIDATE with non-legacy
* flags. E.g. MAP_SYNC is dangerous to use with
* MAP_SHARED as you don't know which consistency model
* you will get. We silently ignore unsupported flags
* with MAP_SHARED to preserve backward compatibility.
*/
flags &= LEGACY_MAP_MASK;
mm: use fallthrough; Convert the various /* fallthrough */ comments to the pseudo-keyword fallthrough; Done via script: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/ Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: http://lkml.kernel.org/r/f62fea5d10eb0ccfc05d87c242a620c261219b66.camel@perches.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 06:08:39 +03:00
fallthrough;
mm: introduce MAP_SHARED_VALIDATE, a mechanism to safely define new mmap flags The mmap(2) syscall suffers from the ABI anti-pattern of not validating unknown flags. However, proposals like MAP_SYNC need a mechanism to define new behavior that is known to fail on older kernels without the support. Define a new MAP_SHARED_VALIDATE flag pattern that is guaranteed to fail on all legacy mmap implementations. It is worth noting that the original proposal was for a standalone MAP_VALIDATE flag. However, when that could not be supported by all archs Linus observed: I see why you *think* you want a bitmap. You think you want a bitmap because you want to make MAP_VALIDATE be part of MAP_SYNC etc, so that people can do ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_SYNC, fd, 0); and "know" that MAP_SYNC actually takes. And I'm saying that whole wish is bogus. You're fundamentally depending on special semantics, just make it explicit. It's already not portable, so don't try to make it so. Rename that MAP_VALIDATE as MAP_SHARED_VALIDATE, make it have a value of 0x3, and make people do ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED_VALIDATE | MAP_SYNC, fd, 0); and then the kernel side is easier too (none of that random garbage playing games with looking at the "MAP_VALIDATE bit", but just another case statement in that map type thing. Boom. Done. Similar to ->fallocate() we also want the ability to validate the support for new flags on a per ->mmap() 'struct file_operations' instance basis. Towards that end arrange for flags to be generically validated against a mmap_supported_flags exported by 'struct file_operations'. By default all existing flags are implicitly supported, but new flags require MAP_SHARED_VALIDATE and per-instance-opt-in. Cc: Jan Kara <jack@suse.cz> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Suggested-by: Christoph Hellwig <hch@lst.de> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-11-01 18:36:30 +03:00
case MAP_SHARED_VALIDATE:
if (flags & ~flags_mask)
return -EOPNOTSUPP;
vfs: don't allow writes to swap files Don't let userspace write to an active swap file because the kernel effectively has a long term lease on the storage and things could get seriously corrupted if we let this happen. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2019-08-20 17:55:16 +03:00
if (prot & PROT_WRITE) {
if (!(file->f_mode & FMODE_WRITE))
return -EACCES;
if (IS_SWAPFILE(file->f_mapping->host))
return -ETXTBSY;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* Make sure we don't allow writing to an append-only
* file..
*/
if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
return -EACCES;
/*
* Make sure there are no mandatory locks on the file.
*/
locks: fix locks_mandatory_locked to respect file-private locks As Trond pointed out, you can currently deadlock yourself by setting a file-private lock on a file that requires mandatory locking and then trying to do I/O on it. Avoid this problem by plumbing some knowledge of file-private locks into the mandatory locking code. In order to do this, we must pass down information about the struct file that's being used to locks_verify_locked. Reported-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: J. Bruce Fields <bfields@redhat.com>
2014-03-10 17:54:15 +04:00
if (locks_verify_locked(file))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -EAGAIN;
vm_flags |= VM_SHARED | VM_MAYSHARE;
if (!(file->f_mode & FMODE_WRITE))
vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
mm: use fallthrough; Convert the various /* fallthrough */ comments to the pseudo-keyword fallthrough; Done via script: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/ Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: http://lkml.kernel.org/r/f62fea5d10eb0ccfc05d87c242a620c261219b66.camel@perches.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 06:08:39 +03:00
fallthrough;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
case MAP_PRIVATE:
if (!(file->f_mode & FMODE_READ))
return -EACCES;
vfs: Commit to never having exectuables on proc and sysfs. Today proc and sysfs do not contain any executable files. Several applications today mount proc or sysfs without noexec and nosuid and then depend on there being no exectuables files on proc or sysfs. Having any executable files show on proc or sysfs would cause a user space visible regression, and most likely security problems. Therefore commit to never allowing executables on proc and sysfs by adding a new flag to mark them as filesystems without executables and enforce that flag. Test the flag where MNT_NOEXEC is tested today, so that the only user visible effect will be that exectuables will be treated as if the execute bit is cleared. The filesystems proc and sysfs do not currently incoporate any executable files so this does not result in any user visible effects. This makes it unnecessary to vet changes to proc and sysfs tightly for adding exectuable files or changes to chattr that would modify existing files, as no matter what the individual file say they will not be treated as exectuable files by the vfs. Not having to vet changes to closely is important as without this we are only one proc_create call (or another goof up in the implementation of notify_change) from having problematic executables on proc. Those mistakes are all too easy to make and would create a situation where there are security issues or the assumptions of some program having to be broken (and cause userspace regressions). Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2015-06-29 22:42:03 +03:00
if (path_noexec(&file->f_path)) {
Fix VM_MAYEXEC calculation .. and clean up the file mapping code while at it. No point in having a "if (file)" repeated twice, and generally doing similar checks in two different sections of the same code Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-16 01:09:55 +04:00
if (vm_flags & VM_EXEC)
return -EPERM;
vm_flags &= ~VM_MAYEXEC;
}
file->f_op is never NULL... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-09-23 00:27:52 +04:00
if (!file->f_op->mmap)
Fix VM_MAYEXEC calculation .. and clean up the file mapping code while at it. No point in having a "if (file)" repeated twice, and generally doing similar checks in two different sections of the same code Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-16 01:09:55 +04:00
return -ENODEV;
mm: shift VM_GROWS* check from mmap_region() to do_mmap_pgoff() mmap() doesn't allow the non-anonymous mappings with VM_GROWS* bit set. In particular this means that mmap_region()->vma_merge(file, vm_flags) must always fail if "vm_flags & VM_GROWS" is set incorrectly. So it does not make sense to check VM_GROWS* after we already allocated the new vma, the only caller, do_mmap_pgoff(), which can pass this flag can do the check itself. And this looks a bit more correct, mmap_region() already unmapped the old mapping at this stage. But if mmap() is going to fail, it should avoid do_munmap() if possible. Note: we check VM_GROWS at the end to ensure that do_mmap_pgoff() won't return EINVAL in the case when it currently returns another error code. Many thanks to Hugh who nacked the buggy v1. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:20:18 +04:00
if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
return -EINVAL;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
break;
default:
return -EINVAL;
}
} else {
switch (flags & MAP_TYPE) {
case MAP_SHARED:
mm: shift VM_GROWS* check from mmap_region() to do_mmap_pgoff() mmap() doesn't allow the non-anonymous mappings with VM_GROWS* bit set. In particular this means that mmap_region()->vma_merge(file, vm_flags) must always fail if "vm_flags & VM_GROWS" is set incorrectly. So it does not make sense to check VM_GROWS* after we already allocated the new vma, the only caller, do_mmap_pgoff(), which can pass this flag can do the check itself. And this looks a bit more correct, mmap_region() already unmapped the old mapping at this stage. But if mmap() is going to fail, it should avoid do_munmap() if possible. Note: we check VM_GROWS at the end to ensure that do_mmap_pgoff() won't return EINVAL in the case when it currently returns another error code. Many thanks to Hugh who nacked the buggy v1. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:20:18 +04:00
if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
return -EINVAL;
mmap: fix petty bug in anonymous shared mmap offset handling Anonymous mappings should ignore offset but shared anonymous mapping forgot to clear it and makes the following legit test program trigger SIGBUS. #include <sys/mman.h> #include <stdio.h> #include <errno.h> #define PAGE_SIZE 4096 int main(void) { char *p; int i; p = mmap(NULL, 2 * PAGE_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, PAGE_SIZE); if (p == MAP_FAILED) { perror("mmap"); return 1; } for (i = 0; i < 2; i++) { printf("page %d\n", i); p[i * 4096] = i; } return 0; } Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Hugh Dickins <hugh@veritas.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-03 18:09:47 +04:00
/*
* Ignore pgoff.
*/
pgoff = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
vm_flags |= VM_SHARED | VM_MAYSHARE;
break;
case MAP_PRIVATE:
/*
* Set pgoff according to addr for anon_vma.
*/
pgoff = addr >> PAGE_SHIFT;
break;
default:
return -EINVAL;
}
}
mm: remove flags argument to mmap_region After the MAP_POPULATE handling has been moved to mmap_region() call sites, the only remaining use of the flags argument is to pass the MAP_NORESERVE flag. This can be just as easily handled by do_mmap_pgoff(), so do that and remove the mmap_region() flags parameter. [akpm@linux-foundation.org: remove double parens] Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:43 +04:00
/*
* Set 'VM_NORESERVE' if we should not account for the
* memory use of this mapping.
*/
if (flags & MAP_NORESERVE) {
/* We honor MAP_NORESERVE if allowed to overcommit */
if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
vm_flags |= VM_NORESERVE;
/* hugetlb applies strict overcommit unless MAP_NORESERVE */
if (file && is_file_hugepages(file))
vm_flags |= VM_NORESERVE;
}
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
addr = mmap_region(file, addr, len, vm_flags, pgoff, uf);
Revert "mm: introduce VM_POPULATE flag to better deal with racy userspace programs" This reverts commit 186930500985 ("mm: introduce VM_POPULATE flag to better deal with racy userspace programs"). VM_POPULATE only has any effect when userspace plays racy games with vmas by trying to unmap and remap memory regions that mmap or mlock are operating on. Also, the only effect of VM_POPULATE when userspace plays such games is that it avoids populating new memory regions that get remapped into the address range that was being operated on by the original mmap or mlock calls. Let's remove VM_POPULATE as there isn't any strong argument to mandate a new vm_flag. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-29 03:26:23 +04:00
if (!IS_ERR_VALUE(addr) &&
((vm_flags & VM_LOCKED) ||
(flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE))
mm: make do_mmap_pgoff return populate as a size in bytes, not as a bool do_mmap_pgoff() rounds up the desired size to the next PAGE_SIZE multiple, however there was no equivalent code in mm_populate(), which caused issues. This could be fixed by introduced the same rounding in mm_populate(), however I think it's preferable to make do_mmap_pgoff() return populate as a size rather than as a boolean, so we don't have to duplicate the size rounding logic in mm_populate(). Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:47 +04:00
*populate = len;
mm: introduce mm_populate() for populating new vmas When creating new mappings using the MAP_POPULATE / MAP_LOCKED flags (or with MCL_FUTURE in effect), we want to populate the pages within the newly created vmas. This may take a while as we may have to read pages from disk, so ideally we want to do this outside of the write-locked mmap_sem region. This change introduces mm_populate(), which is used to defer populating such mappings until after the mmap_sem write lock has been released. This is implemented as a generalization of the former do_mlock_pages(), which accomplished the same task but was using during mlock() / mlockall(). Signed-off-by: Michel Lespinasse <walken@google.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:37 +04:00
return addr;
split mmap This is a straightforward split of do_mmap_pgoff() into two functions: - do_mmap_pgoff() checks the parameters, and calculates the vma flags. Then it calls - mmap_region(), which does the actual mapping Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 10:38:26 +04:00
}
VM: add "vm_mmap()" helper function This continues the theme started with vm_brk() and vm_munmap(): vm_mmap() does the same thing as do_mmap(), but additionally does the required VM locking. This uninlines (and rewrites it to be clearer) do_mmap(), which sadly duplicates it in mm/mmap.c and mm/nommu.c. But that way we don't have to export our internal do_mmap_pgoff() function. Some day we hopefully don't have to export do_mmap() either, if all modular users can become the simpler vm_mmap() instead. We're actually very close to that already, with the notable exception of the (broken) use in i810, and a couple of stragglers in binfmt_elf. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-21 04:13:58 +04:00
mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff() Using this helper allows us to avoid the in-kernel calls to the sys_mmap_pgoff() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_mmap_pgoff(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-03-11 13:34:46 +03:00
unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,
unsigned long fd, unsigned long pgoff)
mm: move sys_mmap_pgoff from util.c Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c, where we'd expect to find such code: especially now that it contains the MAP_HUGETLB handling. Revert mm/util.c to how it was in 2.6.32. This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32, whereas 2.6.33-rc2 reported -ENOSYS. Perhaps validate_mmap_request() should reject it with -EINVAL? Add that later if necessary. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-30 23:17:34 +03:00
{
struct file *file = NULL;
mm/mmap.c: do not initialize retval in mmap_pgoff() When fget() fails we can return -EBADF directly. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:35 +03:00
unsigned long retval;
mm: move sys_mmap_pgoff from util.c Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c, where we'd expect to find such code: especially now that it contains the MAP_HUGETLB handling. Revert mm/util.c to how it was in 2.6.32. This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32, whereas 2.6.33-rc2 reported -ENOSYS. Perhaps validate_mmap_request() should reject it with -EINVAL? Add that later if necessary. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-30 23:17:34 +03:00
if (!(flags & MAP_ANONYMOUS)) {
audit mmap Normal syscall audit doesn't catch 5th argument of syscall. It also doesn't catch the contents of userland structures pointed to be syscall argument, so for both old and new mmap(2) ABI it doesn't record the descriptor we are mapping. For old one it also misses flags. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-30 10:54:44 +04:00
audit_mmap_fd(fd, flags);
mm: move sys_mmap_pgoff from util.c Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c, where we'd expect to find such code: especially now that it contains the MAP_HUGETLB handling. Revert mm/util.c to how it was in 2.6.32. This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32, whereas 2.6.33-rc2 reported -ENOSYS. Perhaps validate_mmap_request() should reject it with -EINVAL? Add that later if necessary. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-30 23:17:34 +03:00
file = fget(fd);
if (!file)
mm/mmap.c: do not initialize retval in mmap_pgoff() When fget() fails we can return -EBADF directly. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:35 +03:00
return -EBADF;
mm/mmap: optimize a branch judgment in ksys_mmap_pgoff() Look at the pseudo code below. It's very clear that, the judgement "!is_file_hugepages(file)" at 3) is duplicated to the one at 1), we can use "else if" to avoid it. And the assignment "retval = -EINVAL" at 2) is only needed by the branch 3), because "retval" will be overwritten at 4). No functional change, but it can reduce the code size. Maybe more clearer? Before: text data bss dec hex filename 28733 1590 1 30324 7674 mm/mmap.o After: text data bss dec hex filename 28701 1590 1 30292 7654 mm/mmap.o ====pseudo code====: if (!(flags & MAP_ANONYMOUS)) { ... 1) if (is_file_hugepages(file)) len = ALIGN(len, huge_page_size(hstate_file(file))); 2) retval = -EINVAL; 3) if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) goto out_fput; } else if (flags & MAP_HUGETLB) { ... } ... 4) retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); out_fput: ... return retval; Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200705080112.1405-1-thunder.leizhen@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:22:59 +03:00
if (is_file_hugepages(file)) {
hugetlbfs: fix mmap failure in unaligned size request The current kernel returns -EINVAL unless a given mmap length is "almost" hugepage aligned. This is because in sys_mmap_pgoff() the given length is passed to vm_mmap_pgoff() as it is without being aligned with hugepage boundary. This is a regression introduced in commit 40716e29243d ("hugetlbfs: fix alignment of huge page requests"), where alignment code is pushed into hugetlb_file_setup() and the variable len in caller side is not changed. To fix this, this patch partially reverts that commit, and adds alignment code in caller side. And it also introduces hstate_sizelog() in order to get proper hstate to specified hugepage size. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=56881 [akpm@linux-foundation.org: fix warning when CONFIG_HUGETLB_PAGE=n] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: <iceman_dvd@yahoo.com> Cc: Steven Truelove <steven.truelove@utoronto.ca> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-08 03:18:13 +04:00
len = ALIGN(len, huge_page_size(hstate_file(file)));
mm/mmap: optimize a branch judgment in ksys_mmap_pgoff() Look at the pseudo code below. It's very clear that, the judgement "!is_file_hugepages(file)" at 3) is duplicated to the one at 1), we can use "else if" to avoid it. And the assignment "retval = -EINVAL" at 2) is only needed by the branch 3), because "retval" will be overwritten at 4). No functional change, but it can reduce the code size. Maybe more clearer? Before: text data bss dec hex filename 28733 1590 1 30324 7674 mm/mmap.o After: text data bss dec hex filename 28701 1590 1 30292 7654 mm/mmap.o ====pseudo code====: if (!(flags & MAP_ANONYMOUS)) { ... 1) if (is_file_hugepages(file)) len = ALIGN(len, huge_page_size(hstate_file(file))); 2) retval = -EINVAL; 3) if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) goto out_fput; } else if (flags & MAP_HUGETLB) { ... } ... 4) retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); out_fput: ... return retval; Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200705080112.1405-1-thunder.leizhen@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:22:59 +03:00
} else if (unlikely(flags & MAP_HUGETLB)) {
retval = -EINVAL;
mmap: allow MAP_HUGETLB for hugetlbfs files v2 It is counterintuitive at best that mmap'ing a hugetlbfs file with MAP_HUGETLB fails, while mmap'ing it without will a) succeed and b) return huge pages. v2: use is_file_hugepages(), as suggested by Jianguo Signed-off-by: Joern Engel <joern@logfs.org> Cc: Jianguo Wu <wujianguo@huawei.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 03:00:26 +04:00
goto out_fput;
mm/mmap: optimize a branch judgment in ksys_mmap_pgoff() Look at the pseudo code below. It's very clear that, the judgement "!is_file_hugepages(file)" at 3) is duplicated to the one at 1), we can use "else if" to avoid it. And the assignment "retval = -EINVAL" at 2) is only needed by the branch 3), because "retval" will be overwritten at 4). No functional change, but it can reduce the code size. Maybe more clearer? Before: text data bss dec hex filename 28733 1590 1 30324 7674 mm/mmap.o After: text data bss dec hex filename 28701 1590 1 30292 7654 mm/mmap.o ====pseudo code====: if (!(flags & MAP_ANONYMOUS)) { ... 1) if (is_file_hugepages(file)) len = ALIGN(len, huge_page_size(hstate_file(file))); 2) retval = -EINVAL; 3) if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) goto out_fput; } else if (flags & MAP_HUGETLB) { ... } ... 4) retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); out_fput: ... return retval; Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200705080112.1405-1-thunder.leizhen@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:22:59 +03:00
}
mm: move sys_mmap_pgoff from util.c Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c, where we'd expect to find such code: especially now that it contains the MAP_HUGETLB handling. Revert mm/util.c to how it was in 2.6.32. This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32, whereas 2.6.33-rc2 reported -ENOSYS. Perhaps validate_mmap_request() should reject it with -EINVAL? Add that later if necessary. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-30 23:17:34 +03:00
} else if (flags & MAP_HUGETLB) {
struct user_struct *user = NULL;
ipc/shmc.c: eliminate ugly 80-col tricks Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 03:01:08 +04:00
struct hstate *hs;
hugetlbfs: fix mmap failure in unaligned size request The current kernel returns -EINVAL unless a given mmap length is "almost" hugepage aligned. This is because in sys_mmap_pgoff() the given length is passed to vm_mmap_pgoff() as it is without being aligned with hugepage boundary. This is a regression introduced in commit 40716e29243d ("hugetlbfs: fix alignment of huge page requests"), where alignment code is pushed into hugetlb_file_setup() and the variable len in caller side is not changed. To fix this, this patch partially reverts that commit, and adds alignment code in caller side. And it also introduces hstate_sizelog() in order to get proper hstate to specified hugepage size. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=56881 [akpm@linux-foundation.org: fix warning when CONFIG_HUGETLB_PAGE=n] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: <iceman_dvd@yahoo.com> Cc: Steven Truelove <steven.truelove@utoronto.ca> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-08 03:18:13 +04:00
mm/mmap: replace SHM_HUGE_MASK with MAP_HUGE_MASK inside mmap_pgoff Commit 091d0d55b286 ("shm: fix null pointer deref when userspace specifies invalid hugepage size") had replaced MAP_HUGE_MASK with SHM_HUGE_MASK. Though both of them contain the same numeric value of 0x3f, MAP_HUGE_MASK flag sounds more appropriate than the other one in the context. Hence change it back. Link: http://lkml.kernel.org/r/20170404045635.616-1-khandual@linux.vnet.ibm.com Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Balbir Singh <bsingharora@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-04 00:55:00 +03:00
hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
shm: fix null pointer deref when userspace specifies invalid hugepage size Dave reported an oops triggered by trinity: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: newseg+0x10d/0x390 PGD cf8c1067 PUD cf8c2067 PMD 0 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC CPU: 2 PID: 7636 Comm: trinity-child2 Not tainted 3.9.0+#67 ... Call Trace: ipcget+0x182/0x380 SyS_shmget+0x5a/0x60 tracesys+0xdd/0xe2 This bug was introduced by commit af73e4d9506d ("hugetlbfs: fix mmap failure in unaligned size request"). Reported-by: Dave Jones <davej@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Li Zefan <lizfan@huawei.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-09 11:08:15 +04:00
if (!hs)
return -EINVAL;
len = ALIGN(len, huge_page_size(hs));
mm: move sys_mmap_pgoff from util.c Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c, where we'd expect to find such code: especially now that it contains the MAP_HUGETLB handling. Revert mm/util.c to how it was in 2.6.32. This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32, whereas 2.6.33-rc2 reported -ENOSYS. Perhaps validate_mmap_request() should reject it with -EINVAL? Add that later if necessary. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-30 23:17:34 +03:00
/*
* VM_NORESERVE is used because the reservations will be
* taken when vm_ops->mmap() is called
* A dummy user value is used because we are not locking
* memory so no accounting is necessary
*/
hugetlbfs: fix mmap failure in unaligned size request The current kernel returns -EINVAL unless a given mmap length is "almost" hugepage aligned. This is because in sys_mmap_pgoff() the given length is passed to vm_mmap_pgoff() as it is without being aligned with hugepage boundary. This is a regression introduced in commit 40716e29243d ("hugetlbfs: fix alignment of huge page requests"), where alignment code is pushed into hugetlb_file_setup() and the variable len in caller side is not changed. To fix this, this patch partially reverts that commit, and adds alignment code in caller side. And it also introduces hstate_sizelog() in order to get proper hstate to specified hugepage size. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=56881 [akpm@linux-foundation.org: fix warning when CONFIG_HUGETLB_PAGE=n] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: <iceman_dvd@yahoo.com> Cc: Steven Truelove <steven.truelove@utoronto.ca> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-08 03:18:13 +04:00
file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB There was some desire in large applications using MAP_HUGETLB or SHM_HUGETLB to use 1GB huge pages on some mappings, and stay with 2MB on others. This is useful together with NUMA policy: use 2MB interleaving on some mappings, but 1GB on local mappings. This patch extends the IPC/SHM syscall interfaces slightly to allow specifying the page size. It borrows some upper bits in the existing flag arguments and allows encoding the log of the desired page size in addition to the *_HUGETLB flag. When 0 is specified the default size is used, this makes the change fully compatible. Extending the internal hugetlb code to handle this is straight forward. Instead of a single mount it just keeps an array of them and selects the right mount based on the specified page size. When no page size is specified it uses the mount of the default page size. The change is not visible in /proc/mounts because internal mounts don't appear there. It also has very little overhead: the additional mounts just consume a super block, but not more memory when not used. I also exported the new flags to the user headers (they were previously under __KERNEL__). Right now only symbols for x86 and some other architecture for 1GB and 2MB are defined. The interface should already work for all other architectures though. Only architectures that define multiple hugetlb sizes actually need it (that is currently x86, tile, powerpc). However tile and powerpc have user configurable hugetlb sizes, so it's not easy to add defines. A program on those architectures would need to query sysfs and use the appropiate log2. [akpm@linux-foundation.org: cleanups] [rientjes@google.com: fix build] [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:34 +04:00
VM_NORESERVE,
&user, HUGETLB_ANONHUGE_INODE,
(flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
mm: move sys_mmap_pgoff from util.c Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c, where we'd expect to find such code: especially now that it contains the MAP_HUGETLB handling. Revert mm/util.c to how it was in 2.6.32. This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32, whereas 2.6.33-rc2 reported -ENOSYS. Perhaps validate_mmap_request() should reject it with -EINVAL? Add that later if necessary. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-30 23:17:34 +03:00
if (IS_ERR(file))
return PTR_ERR(file);
}
flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
mm: make vm_mmap killable All the callers of vm_mmap seem to check for the failure already and bail out in one way or another on the error which means that we can change it to use killable version of vm_mmap_pgoff and return -EINTR if the current task gets killed while waiting for mmap_sem. This also means that vm_mmap_pgoff can be killable by default and drop the additional parameter. This will help in the OOM conditions when the oom victim might be stuck waiting for the mmap_sem for write which in turn can block oom_reaper which relies on the mmap_sem for read to make a forward progress and reclaim the address space of the victim. Please note that load_elf_binary is ignoring vm_mmap error for current->personality & MMAP_PAGE_ZERO case but that shouldn't be a problem because the address is not used anywhere and we never return to the userspace if we got killed. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-24 02:25:30 +03:00
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
mmap: allow MAP_HUGETLB for hugetlbfs files v2 It is counterintuitive at best that mmap'ing a hugetlbfs file with MAP_HUGETLB fails, while mmap'ing it without will a) succeed and b) return huge pages. v2: use is_file_hugepages(), as suggested by Jianguo Signed-off-by: Joern Engel <joern@logfs.org> Cc: Jianguo Wu <wujianguo@huawei.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 03:00:26 +04:00
out_fput:
mm: move sys_mmap_pgoff from util.c Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c, where we'd expect to find such code: especially now that it contains the MAP_HUGETLB handling. Revert mm/util.c to how it was in 2.6.32. This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32, whereas 2.6.33-rc2 reported -ENOSYS. Perhaps validate_mmap_request() should reject it with -EINVAL? Add that later if necessary. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-30 23:17:34 +03:00
if (file)
fput(file);
return retval;
}
mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff() Using this helper allows us to avoid the in-kernel calls to the sys_mmap_pgoff() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_mmap_pgoff(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-03-11 13:34:46 +03:00
SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, pgoff)
{
return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
}
Add generic sys_old_mmap() Add a generic implementation of the old mmap() syscall, which expects its argument in a memory block and switch all architectures over to use it. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Reviewed-by: H. Peter Anvin <hpa@zytor.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Greg Ungerer <gerg@uclinux.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-11 02:21:15 +03:00
#ifdef __ARCH_WANT_SYS_OLD_MMAP
struct mmap_arg_struct {
unsigned long addr;
unsigned long len;
unsigned long prot;
unsigned long flags;
unsigned long fd;
unsigned long offset;
};
SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
{
struct mmap_arg_struct a;
if (copy_from_user(&a, arg, sizeof(a)))
return -EFAULT;
mm/mmap: use offset_in_page macro linux/mm.h provides offset_in_page() macro. Let's use already predefined macro instead of (addr & ~PAGE_MASK). Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:46:54 +03:00
if (offset_in_page(a.offset))
Add generic sys_old_mmap() Add a generic implementation of the old mmap() syscall, which expects its argument in a memory block and switch all architectures over to use it. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Reviewed-by: H. Peter Anvin <hpa@zytor.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Greg Ungerer <gerg@uclinux.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-11 02:21:15 +03:00
return -EINVAL;
mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff() Using this helper allows us to avoid the in-kernel calls to the sys_mmap_pgoff() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_mmap_pgoff(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-03-11 13:34:46 +03:00
return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
a.offset >> PAGE_SHIFT);
Add generic sys_old_mmap() Add a generic implementation of the old mmap() syscall, which expects its argument in a memory block and switch all architectures over to use it. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Reviewed-by: H. Peter Anvin <hpa@zytor.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Greg Ungerer <gerg@uclinux.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-11 02:21:15 +03:00
}
#endif /* __ARCH_WANT_SYS_OLD_MMAP */
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
/*
mm: fix some typos in mm directory No functional change. Link: http://lkml.kernel.org/r/20190118235123.27843-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-06 02:46:22 +03:00
* Some shared mappings will want the pages marked read-only
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
* to track write events. If so, we'll downgrade vm_page_prot
* to the private version (using protection_map[] without the
* VM_SHARED bit).
*/
mm: vm_page_prot: update with WRITE_ONCE/READ_ONCE vma->vm_page_prot is read lockless from the rmap_walk, it may be updated concurrently and this prevents the risk of reading intermediate values. Link: http://lkml.kernel.org/r/1474660305-19222-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:22 +03:00
int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot)
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
{
mm: don't access vm_flags as 'int' The type of vma->vm_flags is 'unsigned long'. Neither 'int' nor 'unsigned int'. This patch fixes such misuse. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> [ Changed to use a typedef - we'll extend it to cover more cases later, since there has been discussion about making it a 64-bit type.. - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-26 14:16:19 +04:00
vm_flags_t vm_flags = vma->vm_flags;
mm, dax: VMA with vm_ops->pfn_mkwrite wants to be write-notified For VM_PFNMAP and VM_MIXEDMAP we use vm_ops->pfn_mkwrite instead of vm_ops->page_mkwrite to notify abort write access. This means we want vma->vm_page_prot to be write-protected if the VMA provides this vm_ops. A theoretical scenario that will cause these missed events is: On writable mapping with vm_ops->pfn_mkwrite, but without vm_ops->page_mkwrite: read fault followed by write access to the pfn. Writable pte will be set up on read fault and write fault will not be generated. I found it examining Dave's complaint on generic/080: http://lkml.kernel.org/g/20150831233803.GO3902@dastard Although I don't think it's the reason. It shouldn't be a problem for ext2/ext4 as they provide both pfn_mkwrite and page_mkwrite. [akpm@linux-foundation.org: add local vm_ops to avoid 80-cols mess] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Yigal Korman <yigal@plexistor.com> Acked-by: Boaz Harrosh <boaz@plexistor.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-23 00:59:12 +03:00
const struct vm_operations_struct *vm_ops = vma->vm_ops;
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
/* If it was private or non-writable, the write bit is already clear */
if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
return 0;
/* The backer wishes to know when pages are first written to? */
mm, dax: VMA with vm_ops->pfn_mkwrite wants to be write-notified For VM_PFNMAP and VM_MIXEDMAP we use vm_ops->pfn_mkwrite instead of vm_ops->page_mkwrite to notify abort write access. This means we want vma->vm_page_prot to be write-protected if the VMA provides this vm_ops. A theoretical scenario that will cause these missed events is: On writable mapping with vm_ops->pfn_mkwrite, but without vm_ops->page_mkwrite: read fault followed by write access to the pfn. Writable pte will be set up on read fault and write fault will not be generated. I found it examining Dave's complaint on generic/080: http://lkml.kernel.org/g/20150831233803.GO3902@dastard Although I don't think it's the reason. It shouldn't be a problem for ext2/ext4 as they provide both pfn_mkwrite and page_mkwrite. [akpm@linux-foundation.org: add local vm_ops to avoid 80-cols mess] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Yigal Korman <yigal@plexistor.com> Acked-by: Boaz Harrosh <boaz@plexistor.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-23 00:59:12 +03:00
if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite))
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
return 1;
mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:55:46 +04:00
/* The open routine did something to the protections that pgprot_modify
* won't preserve? */
mm: vm_page_prot: update with WRITE_ONCE/READ_ONCE vma->vm_page_prot is read lockless from the rmap_walk, it may be updated concurrently and this prevents the risk of reading intermediate values. Link: http://lkml.kernel.org/r/1474660305-19222-1-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 03:01:22 +03:00
if (pgprot_val(vm_page_prot) !=
pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags)))
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
return 0;
mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:55:46 +04:00
/* Do we need to track softdirty? */
if (IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) && !(vm_flags & VM_SOFTDIRTY))
return 1;
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
/* Specialty mapping? */
mm: kill vma flag VM_INSERTPAGE Merge VM_INSERTPAGE into VM_MIXEDMAP. VM_MIXEDMAP VMA can mix pure-pfn ptes, special ptes and normal ptes. Now copy_page_range() always copies VM_MIXEDMAP VMA on fork like VM_PFNMAP. If driver populates whole VMA at mmap() it probably not expects page-faults. This patch removes special check from vma_wants_writenotify() which disables pages write tracking for VMA populated via vm_instert_page(). BDI below mapped file should not use dirty-accounting, moreover do_wp_page() can handle this. vm_insert_page() still marks vma after first usage. Usually it is called from f_op->mmap() handler under mm->mmap_sem write-lock, so it able to change vma->vm_flags. Caller must set VM_MIXEDMAP at mmap time if it wants to call this function from other places, for example from page-fault handler. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Carsten Otte <cotte@de.ibm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Eric Paris <eparis@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Kentaro Takeda <takedakn@nttdata.co.jp> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Venkatesh Pallipadi <venki@google.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:28:40 +04:00
if (vm_flags & VM_PFNMAP)
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
return 0;
/* Can the mapping track the dirty pages? */
return vma->vm_file && vma->vm_file->f_mapping &&
bdi: replace BDI_CAP_NO_{WRITEBACK,ACCT_DIRTY} with a single flag Replace the two negative flags that are always used together with a single positive flag that indicates the writeback capability instead of two related non-capabilities. Also remove the pointless wrappers to just check the flag. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-24 09:51:40 +03:00
mapping_can_writeback(vma->vm_file->f_mapping);
Remove fs.h from mm.h Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-30 02:36:13 +04:00
}
Stop playing silly games with the VM_ACCOUNT flag The mmap_region() code would temporarily set the VM_ACCOUNT flag for anonymous shared mappings just to inform shmem_zero_setup() that it should enable accounting for the resulting shm object. It would then clear the flag after calling ->mmap (for the /dev/zero case) or doing shmem_zero_setup() (for the MAP_ANON case). This just resulted in vma merge issues, but also made for just unnecessary confusion. Use the already-existing VM_NORESERVE flag for this instead, and let shmem_{zero|file}_setup() just figure it out from that. This also happens to make it obvious that the new DRI2 GEM layer uses a non-reserving backing store for its object allocation - which is quite possibly not intentional. But since I didn't want to change semantics in this patch, I left it alone, and just updated the caller to use the new flag semantics. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-01 02:08:56 +03:00
/*
* We account for memory if it's a private writeable mapping,
Do not account for the address space used by hugetlbfs using VM_ACCOUNT When overcommit is disabled, the core VM accounts for pages used by anonymous shared, private mappings and special mappings. It keeps track of VMAs that should be accounted for with VM_ACCOUNT and VMAs that never had a reserve with VM_NORESERVE. Overcommit for hugetlbfs is much riskier than overcommit for base pages due to contiguity requirements. It avoids overcommiting on both shared and private mappings using reservation counters that are checked and updated during mmap(). This ensures (within limits) that hugepages exist in the future when faults occurs or it is too easy to applications to be SIGKILLed. As hugetlbfs makes its own reservations of a different unit to the base page size, VM_ACCOUNT should never be set. Even if the units were correct, we would double account for the usage in the core VM and hugetlbfs. VM_NORESERVE may be set because an application can request no reserves be made for hugetlbfs at the risk of getting killed later. With commit fc8744adc870a8d4366908221508bb113d8b72ee, VM_NORESERVE and VM_ACCOUNT are getting unconditionally set for hugetlbfs-backed mappings. This breaks the accounting for both the core VM and hugetlbfs, can trigger an OOM storm when hugepage pools are too small lockups and corrupted counters otherwise are used. This patch brings hugetlbfs more in line with how the core VM treats VM_NORESERVE but prevents VM_ACCOUNT being set. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-10 17:02:27 +03:00
* not hugepages and VM_NORESERVE wasn't set.
Stop playing silly games with the VM_ACCOUNT flag The mmap_region() code would temporarily set the VM_ACCOUNT flag for anonymous shared mappings just to inform shmem_zero_setup() that it should enable accounting for the resulting shm object. It would then clear the flag after calling ->mmap (for the /dev/zero case) or doing shmem_zero_setup() (for the MAP_ANON case). This just resulted in vma merge issues, but also made for just unnecessary confusion. Use the already-existing VM_NORESERVE flag for this instead, and let shmem_{zero|file}_setup() just figure it out from that. This also happens to make it obvious that the new DRI2 GEM layer uses a non-reserving backing store for its object allocation - which is quite possibly not intentional. But since I didn't want to change semantics in this patch, I left it alone, and just updated the caller to use the new flag semantics. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-01 02:08:56 +03:00
*/
mm: don't access vm_flags as 'int' The type of vma->vm_flags is 'unsigned long'. Neither 'int' nor 'unsigned int'. This patch fixes such misuse. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> [ Changed to use a typedef - we'll extend it to cover more cases later, since there has been discussion about making it a 64-bit type.. - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-26 14:16:19 +04:00
static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
Stop playing silly games with the VM_ACCOUNT flag The mmap_region() code would temporarily set the VM_ACCOUNT flag for anonymous shared mappings just to inform shmem_zero_setup() that it should enable accounting for the resulting shm object. It would then clear the flag after calling ->mmap (for the /dev/zero case) or doing shmem_zero_setup() (for the MAP_ANON case). This just resulted in vma merge issues, but also made for just unnecessary confusion. Use the already-existing VM_NORESERVE flag for this instead, and let shmem_{zero|file}_setup() just figure it out from that. This also happens to make it obvious that the new DRI2 GEM layer uses a non-reserving backing store for its object allocation - which is quite possibly not intentional. But since I didn't want to change semantics in this patch, I left it alone, and just updated the caller to use the new flag semantics. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-01 02:08:56 +03:00
{
Do not account for the address space used by hugetlbfs using VM_ACCOUNT When overcommit is disabled, the core VM accounts for pages used by anonymous shared, private mappings and special mappings. It keeps track of VMAs that should be accounted for with VM_ACCOUNT and VMAs that never had a reserve with VM_NORESERVE. Overcommit for hugetlbfs is much riskier than overcommit for base pages due to contiguity requirements. It avoids overcommiting on both shared and private mappings using reservation counters that are checked and updated during mmap(). This ensures (within limits) that hugepages exist in the future when faults occurs or it is too easy to applications to be SIGKILLed. As hugetlbfs makes its own reservations of a different unit to the base page size, VM_ACCOUNT should never be set. Even if the units were correct, we would double account for the usage in the core VM and hugetlbfs. VM_NORESERVE may be set because an application can request no reserves be made for hugetlbfs at the risk of getting killed later. With commit fc8744adc870a8d4366908221508bb113d8b72ee, VM_NORESERVE and VM_ACCOUNT are getting unconditionally set for hugetlbfs-backed mappings. This breaks the accounting for both the core VM and hugetlbfs, can trigger an OOM storm when hugepage pools are too small lockups and corrupted counters otherwise are used. This patch brings hugetlbfs more in line with how the core VM treats VM_NORESERVE but prevents VM_ACCOUNT being set. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-10 17:02:27 +03:00
/*
* hugetlb has its own accounting separate from the core VM
* VM_HUGETLB may not be set yet so we cannot check for that flag.
*/
if (file && is_file_hugepages(file))
return 0;
Stop playing silly games with the VM_ACCOUNT flag The mmap_region() code would temporarily set the VM_ACCOUNT flag for anonymous shared mappings just to inform shmem_zero_setup() that it should enable accounting for the resulting shm object. It would then clear the flag after calling ->mmap (for the /dev/zero case) or doing shmem_zero_setup() (for the MAP_ANON case). This just resulted in vma merge issues, but also made for just unnecessary confusion. Use the already-existing VM_NORESERVE flag for this instead, and let shmem_{zero|file}_setup() just figure it out from that. This also happens to make it obvious that the new DRI2 GEM layer uses a non-reserving backing store for its object allocation - which is quite possibly not intentional. But since I didn't want to change semantics in this patch, I left it alone, and just updated the caller to use the new flag semantics. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-01 02:08:56 +03:00
return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
}
split mmap This is a straightforward split of do_mmap_pgoff() into two functions: - do_mmap_pgoff() checks the parameters, and calculates the vma flags. Then it calls - mmap_region(), which does the actual mapping Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 10:38:26 +04:00
unsigned long mmap_region(struct file *file, unsigned long addr,
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
struct list_head *uf)
split mmap This is a straightforward split of do_mmap_pgoff() into two functions: - do_mmap_pgoff() checks the parameters, and calculates the vma flags. Then it calls - mmap_region(), which does the actual mapping Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 10:38:26 +04:00
{
struct mm_struct *mm = current->mm;
mm: mmap: merge vma after call_mmap() if possible The vm_flags may be changed after call_mmap() because drivers may set some flags for their own purpose. As a result, we failed to merge the adjacent vma due to the different vm_flags as userspace can't pass in the same one. Try to merge vma after call_mmap() to fix this issue. Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1594954065-23733-1-git-send-email-linmiaohe@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:34 +03:00
struct vm_area_struct *vma, *prev, *merge;
split mmap This is a straightforward split of do_mmap_pgoff() into two functions: - do_mmap_pgoff() checks the parameters, and calculates the vma flags. Then it calls - mmap_region(), which does the actual mapping Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 10:38:26 +04:00
int error;
struct rb_node **rb_link, *rb_parent;
unsigned long charged = 0;
mm/mmap: check for RLIMIT_AS before unmapping Fix a corner case for MAP_FIXED when requested mapping length is larger than rlimit for virtual memory. In such case any overlapping mappings are unmapped before we check for the limit and return ENOMEM. The check is moved before the loop that unmaps overlapping parts of existing mappings. When we are about to hit the limit (currently mapped pages + len > limit) we scan for overlapping pages and check again accounting for them. This fixes situation when userspace program expects that the previous mappings are preserved after the mmap() syscall has returned with error. (POSIX clearly states that successfull mapping shall replace any previous mappings.) This corner case was found and can be tested with LTP testcase: testcases/open_posix_testsuite/conformance/interfaces/mmap/24-2.c In this case the mmap, which is clearly over current limit, unmaps dynamic libraries and the testcase segfaults right after returning into userspace. I've also looked at the second instance of the unmapping loop in the do_brk(). The do_brk() is called from brk() syscall and from vm_brk(). The brk() syscall checks for overlapping mappings and bails out when there are any (so it can't be triggered from the brk syscall). The vm_brk() is called only from binmft handlers so it shouldn't be triggered unless binmft handler created overlapping mappings. Signed-off-by: Cyril Hrubis <chrubis@suse.cz> Reviewed-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:33 +04:00
/* Check against address space limit. */
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
mm/mmap: check for RLIMIT_AS before unmapping Fix a corner case for MAP_FIXED when requested mapping length is larger than rlimit for virtual memory. In such case any overlapping mappings are unmapped before we check for the limit and return ENOMEM. The check is moved before the loop that unmaps overlapping parts of existing mappings. When we are about to hit the limit (currently mapped pages + len > limit) we scan for overlapping pages and check again accounting for them. This fixes situation when userspace program expects that the previous mappings are preserved after the mmap() syscall has returned with error. (POSIX clearly states that successfull mapping shall replace any previous mappings.) This corner case was found and can be tested with LTP testcase: testcases/open_posix_testsuite/conformance/interfaces/mmap/24-2.c In this case the mmap, which is clearly over current limit, unmaps dynamic libraries and the testcase segfaults right after returning into userspace. I've also looked at the second instance of the unmapping loop in the do_brk(). The do_brk() is called from brk() syscall and from vm_brk(). The brk() syscall checks for overlapping mappings and bails out when there are any (so it can't be triggered from the brk syscall). The vm_brk() is called only from binmft handlers so it shouldn't be triggered unless binmft handler created overlapping mappings. Signed-off-by: Cyril Hrubis <chrubis@suse.cz> Reviewed-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:33 +04:00
unsigned long nr_pages;
/*
* MAP_FIXED may remove pages of mappings that intersects with
* requested mapping. Account for the pages it would unmap.
*/
nr_pages = count_vma_pages_range(mm, addr, addr + len);
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
if (!may_expand_vm(mm, vm_flags,
(len >> PAGE_SHIFT) - nr_pages))
mm/mmap: check for RLIMIT_AS before unmapping Fix a corner case for MAP_FIXED when requested mapping length is larger than rlimit for virtual memory. In such case any overlapping mappings are unmapped before we check for the limit and return ENOMEM. The check is moved before the loop that unmaps overlapping parts of existing mappings. When we are about to hit the limit (currently mapped pages + len > limit) we scan for overlapping pages and check again accounting for them. This fixes situation when userspace program expects that the previous mappings are preserved after the mmap() syscall has returned with error. (POSIX clearly states that successfull mapping shall replace any previous mappings.) This corner case was found and can be tested with LTP testcase: testcases/open_posix_testsuite/conformance/interfaces/mmap/24-2.c In this case the mmap, which is clearly over current limit, unmaps dynamic libraries and the testcase segfaults right after returning into userspace. I've also looked at the second instance of the unmapping loop in the do_brk(). The do_brk() is called from brk() syscall and from vm_brk(). The brk() syscall checks for overlapping mappings and bails out when there are any (so it can't be triggered from the brk syscall). The vm_brk() is called only from binmft handlers so it shouldn't be triggered unless binmft handler created overlapping mappings. Signed-off-by: Cyril Hrubis <chrubis@suse.cz> Reviewed-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:33 +04:00
return -ENOMEM;
}
mm/mmap: add inline munmap_vma_range() for code readability There are two locations that have a block of code for munmapping a vma range. Change those two locations to use a function and add meaningful comments about what happens to the arguments, which was unclear in the previous code. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200818154707.2515169-2-Liam.Howlett@Oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 02:14:09 +03:00
/* Clear old maps, set up prev, rb_link, rb_parent, and uf */
if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
return -ENOMEM;
Stop playing silly games with the VM_ACCOUNT flag The mmap_region() code would temporarily set the VM_ACCOUNT flag for anonymous shared mappings just to inform shmem_zero_setup() that it should enable accounting for the resulting shm object. It would then clear the flag after calling ->mmap (for the /dev/zero case) or doing shmem_zero_setup() (for the MAP_ANON case). This just resulted in vma merge issues, but also made for just unnecessary confusion. Use the already-existing VM_NORESERVE flag for this instead, and let shmem_{zero|file}_setup() just figure it out from that. This also happens to make it obvious that the new DRI2 GEM layer uses a non-reserving backing store for its object allocation - which is quite possibly not intentional. But since I didn't want to change semantics in this patch, I left it alone, and just updated the caller to use the new flag semantics. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-01 02:08:56 +03:00
/*
* Private writable mapping: check memory availability
*/
Do not account for the address space used by hugetlbfs using VM_ACCOUNT When overcommit is disabled, the core VM accounts for pages used by anonymous shared, private mappings and special mappings. It keeps track of VMAs that should be accounted for with VM_ACCOUNT and VMAs that never had a reserve with VM_NORESERVE. Overcommit for hugetlbfs is much riskier than overcommit for base pages due to contiguity requirements. It avoids overcommiting on both shared and private mappings using reservation counters that are checked and updated during mmap(). This ensures (within limits) that hugepages exist in the future when faults occurs or it is too easy to applications to be SIGKILLed. As hugetlbfs makes its own reservations of a different unit to the base page size, VM_ACCOUNT should never be set. Even if the units were correct, we would double account for the usage in the core VM and hugetlbfs. VM_NORESERVE may be set because an application can request no reserves be made for hugetlbfs at the risk of getting killed later. With commit fc8744adc870a8d4366908221508bb113d8b72ee, VM_NORESERVE and VM_ACCOUNT are getting unconditionally set for hugetlbfs-backed mappings. This breaks the accounting for both the core VM and hugetlbfs, can trigger an OOM storm when hugepage pools are too small lockups and corrupted counters otherwise are used. This patch brings hugetlbfs more in line with how the core VM treats VM_NORESERVE but prevents VM_ACCOUNT being set. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-10 17:02:27 +03:00
if (accountable_mapping(file, vm_flags)) {
Stop playing silly games with the VM_ACCOUNT flag The mmap_region() code would temporarily set the VM_ACCOUNT flag for anonymous shared mappings just to inform shmem_zero_setup() that it should enable accounting for the resulting shm object. It would then clear the flag after calling ->mmap (for the /dev/zero case) or doing shmem_zero_setup() (for the MAP_ANON case). This just resulted in vma merge issues, but also made for just unnecessary confusion. Use the already-existing VM_NORESERVE flag for this instead, and let shmem_{zero|file}_setup() just figure it out from that. This also happens to make it obvious that the new DRI2 GEM layer uses a non-reserving backing store for its object allocation - which is quite possibly not intentional. But since I didn't want to change semantics in this patch, I left it alone, and just updated the caller to use the new flag semantics. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-01 02:08:56 +03:00
charged = len >> PAGE_SHIFT;
mm: collapse security_vm_enough_memory() variants into a single function Collapse security_vm_enough_memory() variants into a single function. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Morris <jmorris@namei.org>
2012-02-13 07:58:52 +04:00
if (security_vm_enough_memory_mm(mm, charged))
Stop playing silly games with the VM_ACCOUNT flag The mmap_region() code would temporarily set the VM_ACCOUNT flag for anonymous shared mappings just to inform shmem_zero_setup() that it should enable accounting for the resulting shm object. It would then clear the flag after calling ->mmap (for the /dev/zero case) or doing shmem_zero_setup() (for the MAP_ANON case). This just resulted in vma merge issues, but also made for just unnecessary confusion. Use the already-existing VM_NORESERVE flag for this instead, and let shmem_{zero|file}_setup() just figure it out from that. This also happens to make it obvious that the new DRI2 GEM layer uses a non-reserving backing store for its object allocation - which is quite possibly not intentional. But since I didn't want to change semantics in this patch, I left it alone, and just updated the caller to use the new flag semantics. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-01 02:08:56 +03:00
return -ENOMEM;
vm_flags |= VM_ACCOUNT;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/*
Fix OOPS in mmap_region() when merging adjacent VM_LOCKED file segments As of commit ba470de43188cdbff795b5da43a1474523c6c2fb ("map: handle mlocked pages during map, remap, unmap") we now use the 'vma' variable at the end of mmap_region() to handle the page-in of newly mapped mlocked pages. However, if we merged adjacent vma's together, the vma we're using may be stale. We historically consciously avoided using it after the merge operation, but that got overlooked when redoing the locked page handling. This commit simplifies mmap_region() by doing any vma merges early, avoiding the issue entirely, and 'vma' will always be valid. As pointed out by Hugh Dickins, this depends on any drivers that change the page offset of flags to have set one of the VM_SPECIAL bits (so that they cannot trigger the early merge logic), but that's true in general. Reported-and-tested-by: Maksim Yevmenkin <maksim.yevmenkin@gmail.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-30 04:46:42 +03:00
* Can we just expand an old mapping?
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
vma = vma_merge(mm, prev, addr, addr + len, vm_flags,
NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX);
Fix OOPS in mmap_region() when merging adjacent VM_LOCKED file segments As of commit ba470de43188cdbff795b5da43a1474523c6c2fb ("map: handle mlocked pages during map, remap, unmap") we now use the 'vma' variable at the end of mmap_region() to handle the page-in of newly mapped mlocked pages. However, if we merged adjacent vma's together, the vma we're using may be stale. We historically consciously avoided using it after the merge operation, but that got overlooked when redoing the locked page handling. This commit simplifies mmap_region() by doing any vma merges early, avoiding the issue entirely, and 'vma' will always be valid. As pointed out by Hugh Dickins, this depends on any drivers that change the page offset of flags to have set one of the VM_SPECIAL bits (so that they cannot trigger the early merge logic), but that's true in general. Reported-and-tested-by: Maksim Yevmenkin <maksim.yevmenkin@gmail.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-30 04:46:42 +03:00
if (vma)
goto out;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* Determine the object being mapped and call the appropriate
* specific mapper. the address has already been validated, but
* not unmapped, but the maps are removed from the list.
*/
mm: make vm_area_alloc() initialize core fields Like vm_area_dup(), it initializes the anon_vma_chain head, and the basic mm pointer. The rest of the fields end up being different for different users, although the plan is to also initialize the 'vm_ops' field to a dummy entry. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-22 01:24:03 +03:00
vma = vm_area_alloc(mm);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (!vma) {
error = -ENOMEM;
goto unacct_error;
}
vma->vm_start = addr;
vma->vm_end = addr + len;
vma->vm_flags = vm_flags;
setup vma->vm_page_prot by vm_get_page_prot() This patch uses vm_get_page_prot() to setup vma->vm_page_prot. Though inside vm_get_page_prot() the protection flags is AND with (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED), it does not hurt correct code. Signed-off-by: Coly Li <coyli@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 10:39:15 +04:00
vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
vma->vm_pgoff = pgoff;
if (file) {
if (vm_flags & VM_DENYWRITE) {
error = deny_write_access(file);
if (error)
goto free_vma;
}
mm: allow drivers to prevent new writable mappings This patch (of 6): The i_mmap_writable field counts existing writable mappings of an address_space. To allow drivers to prevent new writable mappings, make this counter signed and prevent new writable mappings if it is negative. This is modelled after i_writecount and DENYWRITE. This will be required by the shmem-sealing infrastructure to prevent any new writable mappings after the WRITE seal has been set. In case there exists a writable mapping, this operation will fail with EBUSY. Note that we rely on the fact that iff you already own a writable mapping, you can increase the counter without using the helpers. This is the same that we do for i_writecount. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ryan Lortie <desrt@desrt.ca> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <zonque@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-09 01:25:25 +04:00
if (vm_flags & VM_SHARED) {
error = mapping_map_writable(file->f_mapping);
if (error)
goto allow_write_and_free_vma;
}
/* ->mmap() can change vma->vm_file, but must guarantee that
* vma_link() below can deny write-access if VM_DENYWRITE is set
* and map writably if VM_SHARED is set. This usually means the
* new file must not have been exposed to user-space, yet.
*/
make get_file() return its argument simplifies a bunch of callers... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-08-27 22:48:26 +04:00
vma->vm_file = get_file(file);
mm: use helper for calling f_op->mmap() Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-20 18:51:23 +03:00
error = call_mmap(file, vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (error)
goto unmap_and_free_vma;
mmap: save some cycles for the shared anonymous mapping shmem_zero_setup() does not change vm_start, pgoff or vm_flags, only some drivers change them (such as /driver/video/bfin-t350mcqb-fb.c). Move these codes to a more proper place to save cycles for shared anonymous mapping. Signed-off-by: Huang Shijie <shijie8@gmail.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 04:03:41 +04:00
mm: mmap: merge vma after call_mmap() if possible The vm_flags may be changed after call_mmap() because drivers may set some flags for their own purpose. As a result, we failed to merge the adjacent vma due to the different vm_flags as userspace can't pass in the same one. Try to merge vma after call_mmap() to fix this issue. Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1594954065-23733-1-git-send-email-linmiaohe@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:34 +03:00
/* If vm_flags changed after call_mmap(), we should try merge vma again
* as we may succeed this time.
*/
if (unlikely(vm_flags != vma->vm_flags && prev)) {
merge = vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_flags,
NULL, vma->vm_file, vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX);
if (merge) {
mm: mmap: Fix general protection fault in unlink_file_vma() The syzbot reported the below general protection fault: general protection fault, probably for non-canonical address 0xe00eeaee0000003b: 0000 [#1] PREEMPT SMP KASAN KASAN: maybe wild-memory-access in range [0x00777770000001d8-0x00777770000001df] CPU: 1 PID: 10488 Comm: syz-executor721 Not tainted 5.9.0-rc3-syzkaller #0 RIP: 0010:unlink_file_vma+0x57/0xb0 mm/mmap.c:164 Call Trace: free_pgtables+0x1b3/0x2f0 mm/memory.c:415 exit_mmap+0x2c0/0x530 mm/mmap.c:3184 __mmput+0x122/0x470 kernel/fork.c:1076 mmput+0x53/0x60 kernel/fork.c:1097 exit_mm kernel/exit.c:483 [inline] do_exit+0xa8b/0x29f0 kernel/exit.c:793 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:136 [inline] exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:167 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:242 entry_SYSCALL_64_after_hwframe+0x44/0xa9 It's because the ->mmap() callback can change vma->vm_file and fput the original file. But the commit d70cec898324 ("mm: mmap: merge vma after call_mmap() if possible") failed to catch this case and always fput() the original file, hence add an extra fput(). [ Thanks Hillf for pointing this extra fput() out. ] Fixes: d70cec898324 ("mm: mmap: merge vma after call_mmap() if possible") Reported-by: syzbot+c5d5a51dcbb558ca0cb5@syzkaller.appspotmail.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christian König <ckoenig.leichtzumerken@gmail.com> Cc: Hongxiang Lou <louhongxiang@huawei.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Dave Airlie <airlied@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: John Hubbard <jhubbard@nvidia.com> Link: https://lkml.kernel.org/r/20200916090733.31427-1-linmiaohe@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-11 09:16:34 +03:00
/* ->mmap() can change vma->vm_file and fput the original file. So
* fput the vma->vm_file here or we would add an extra fput for file
* and cause general protection fault ultimately.
*/
fput(vma->vm_file);
mm: mmap: merge vma after call_mmap() if possible The vm_flags may be changed after call_mmap() because drivers may set some flags for their own purpose. As a result, we failed to merge the adjacent vma due to the different vm_flags as userspace can't pass in the same one. Try to merge vma after call_mmap() to fix this issue. Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1594954065-23733-1-git-send-email-linmiaohe@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:34 +03:00
vm_area_free(vma);
vma = merge;
/* Update vm_flags and possible addr to pick up the change. We don't
* warn here if addr changed as the vma is not linked by vma_link().
*/
addr = vma->vm_start;
vm_flags = vma->vm_flags;
goto unmap_writable;
}
}
mmap: save some cycles for the shared anonymous mapping shmem_zero_setup() does not change vm_start, pgoff or vm_flags, only some drivers change them (such as /driver/video/bfin-t350mcqb-fb.c). Move these codes to a more proper place to save cycles for shared anonymous mapping. Signed-off-by: Huang Shijie <shijie8@gmail.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 04:03:41 +04:00
/* Can addr have changed??
*
* Answer: Yes, several device drivers can do it in their
* f_op->mmap method. -DaveM
mm: WARN_ON_ONCE if f_op->mmap() change vma's start address During reviewing the source code, I found a comment which mention that after f_op->mmap(), vma's start address can be changed. I didn't verify that it is really possible, because there are so many f_op->mmap() implementation. But if there are some mmap() which change vma's start address, it is possible error situation, because we already prepare prev vma, rb_link and rb_parent and these are related to original address. So add WARN_ON_ONCE for finding that this situtation really happens. Signed-off-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:51:53 +04:00
* Bug: If addr is changed, prev, rb_link, rb_parent should
* be updated for vma_link()
mmap: save some cycles for the shared anonymous mapping shmem_zero_setup() does not change vm_start, pgoff or vm_flags, only some drivers change them (such as /driver/video/bfin-t350mcqb-fb.c). Move these codes to a more proper place to save cycles for shared anonymous mapping. Signed-off-by: Huang Shijie <shijie8@gmail.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 04:03:41 +04:00
*/
mm: WARN_ON_ONCE if f_op->mmap() change vma's start address During reviewing the source code, I found a comment which mention that after f_op->mmap(), vma's start address can be changed. I didn't verify that it is really possible, because there are so many f_op->mmap() implementation. But if there are some mmap() which change vma's start address, it is possible error situation, because we already prepare prev vma, rb_link and rb_parent and these are related to original address. So add WARN_ON_ONCE for finding that this situtation really happens. Signed-off-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:51:53 +04:00
WARN_ON_ONCE(addr != vma->vm_start);
mmap: save some cycles for the shared anonymous mapping shmem_zero_setup() does not change vm_start, pgoff or vm_flags, only some drivers change them (such as /driver/video/bfin-t350mcqb-fb.c). Move these codes to a more proper place to save cycles for shared anonymous mapping. Signed-off-by: Huang Shijie <shijie8@gmail.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 04:03:41 +04:00
addr = vma->vm_start;
vm_flags = vma->vm_flags;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
} else if (vm_flags & VM_SHARED) {
error = shmem_zero_setup(vma);
if (error)
goto free_vma;
mm: fix vma_is_anonymous() false-positives vma_is_anonymous() relies on ->vm_ops being NULL to detect anonymous VMA. This is unreliable as ->mmap may not set ->vm_ops. False-positive vma_is_anonymous() may lead to crashes: next ffff8801ce5e7040 prev ffff8801d20eca50 mm ffff88019c1e13c0 prot 27 anon_vma ffff88019680cdd8 vm_ops 0000000000000000 pgoff 0 file ffff8801b2ec2d00 private_data 0000000000000000 flags: 0xff(read|write|exec|shared|mayread|maywrite|mayexec|mayshare) ------------[ cut here ]------------ kernel BUG at mm/memory.c:1422! invalid opcode: 0000 [#1] SMP KASAN CPU: 0 PID: 18486 Comm: syz-executor3 Not tainted 4.18.0-rc3+ #136 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:zap_pmd_range mm/memory.c:1421 [inline] RIP: 0010:zap_pud_range mm/memory.c:1466 [inline] RIP: 0010:zap_p4d_range mm/memory.c:1487 [inline] RIP: 0010:unmap_page_range+0x1c18/0x2220 mm/memory.c:1508 Call Trace: unmap_single_vma+0x1a0/0x310 mm/memory.c:1553 zap_page_range_single+0x3cc/0x580 mm/memory.c:1644 unmap_mapping_range_vma mm/memory.c:2792 [inline] unmap_mapping_range_tree mm/memory.c:2813 [inline] unmap_mapping_pages+0x3a7/0x5b0 mm/memory.c:2845 unmap_mapping_range+0x48/0x60 mm/memory.c:2880 truncate_pagecache+0x54/0x90 mm/truncate.c:800 truncate_setsize+0x70/0xb0 mm/truncate.c:826 simple_setattr+0xe9/0x110 fs/libfs.c:409 notify_change+0xf13/0x10f0 fs/attr.c:335 do_truncate+0x1ac/0x2b0 fs/open.c:63 do_sys_ftruncate+0x492/0x560 fs/open.c:205 __do_sys_ftruncate fs/open.c:215 [inline] __se_sys_ftruncate fs/open.c:213 [inline] __x64_sys_ftruncate+0x59/0x80 fs/open.c:213 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Reproducer: #include <stdio.h> #include <stddef.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/ioctl.h> #include <sys/mman.h> #include <unistd.h> #include <fcntl.h> #define KCOV_INIT_TRACE _IOR('c', 1, unsigned long) #define KCOV_ENABLE _IO('c', 100) #define KCOV_DISABLE _IO('c', 101) #define COVER_SIZE (1024<<10) #define KCOV_TRACE_PC 0 #define KCOV_TRACE_CMP 1 int main(int argc, char **argv) { int fd; unsigned long *cover; system("mount -t debugfs none /sys/kernel/debug"); fd = open("/sys/kernel/debug/kcov", O_RDWR); ioctl(fd, KCOV_INIT_TRACE, COVER_SIZE); cover = mmap(NULL, COVER_SIZE * sizeof(unsigned long), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); munmap(cover, COVER_SIZE * sizeof(unsigned long)); cover = mmap(NULL, COVER_SIZE * sizeof(unsigned long), PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); memset(cover, 0, COVER_SIZE * sizeof(unsigned long)); ftruncate(fd, 3UL << 20); return 0; } This can be fixed by assigning anonymous VMAs own vm_ops and not relying on it being NULL. If ->mmap() failed to set ->vm_ops, mmap_region() will set it to dummy_vm_ops. This way we will have non-NULL ->vm_ops for all VMAs. Link: http://lkml.kernel.org/r/20180724121139.62570-4-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: syzbot+3f84280d52be9b7083cc@syzkaller.appspotmail.com Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-27 02:37:35 +03:00
} else {
vma_set_anonymous(vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: Introduce arch_validate_flags() Similarly to arch_validate_prot() called from do_mprotect_pkey(), an architecture may need to sanity-check the new vm_flags. Define a dummy function always returning true. In addition to do_mprotect_pkey(), also invoke it from mmap_region() prior to updating vma->vm_page_prot to allow the architecture code to veto potentially inconsistent vm_flags. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org>
2019-11-25 20:27:06 +03:00
/* Allow architectures to sanity-check the vm_flags */
if (!arch_validate_flags(vma->vm_flags)) {
error = -EINVAL;
if (file)
goto unmap_and_free_vma;
else
goto free_vma;
}
Fix OOPS in mmap_region() when merging adjacent VM_LOCKED file segments As of commit ba470de43188cdbff795b5da43a1474523c6c2fb ("map: handle mlocked pages during map, remap, unmap") we now use the 'vma' variable at the end of mmap_region() to handle the page-in of newly mapped mlocked pages. However, if we merged adjacent vma's together, the vma we're using may be stale. We historically consciously avoided using it after the merge operation, but that got overlooked when redoing the locked page handling. This commit simplifies mmap_region() by doing any vma merges early, avoiding the issue entirely, and 'vma' will always be valid. As pointed out by Hugh Dickins, this depends on any drivers that change the page offset of flags to have set one of the VM_SPECIAL bits (so that they cannot trigger the early merge logic), but that's true in general. Reported-and-tested-by: Maksim Yevmenkin <maksim.yevmenkin@gmail.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-30 04:46:42 +03:00
vma_link(mm, vma, prev, rb_link, rb_parent);
mmap_region: cleanup the final vma_merge() related code It is not easy to actually understand the "if (!file || !vma_merge())" code, turn it into "if (file && vma_merge())". This makes immediately obvious that the subsequent "if (file)" is superfluous. As Hugh Dickins pointed out, we can also factor out the ->i_writecount corrections, and add a small comment about that. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 13:12:10 +04:00
/* Once vma denies write, undo our temporary denial count */
mm: allow drivers to prevent new writable mappings This patch (of 6): The i_mmap_writable field counts existing writable mappings of an address_space. To allow drivers to prevent new writable mappings, make this counter signed and prevent new writable mappings if it is negative. This is modelled after i_writecount and DENYWRITE. This will be required by the shmem-sealing infrastructure to prevent any new writable mappings after the WRITE seal has been set. In case there exists a writable mapping, this operation will fail with EBUSY. Note that we rely on the fact that iff you already own a writable mapping, you can increase the counter without using the helpers. This is the same that we do for i_writecount. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ryan Lortie <desrt@desrt.ca> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <zonque@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-09 01:25:25 +04:00
if (file) {
mm: mmap: merge vma after call_mmap() if possible The vm_flags may be changed after call_mmap() because drivers may set some flags for their own purpose. As a result, we failed to merge the adjacent vma due to the different vm_flags as userspace can't pass in the same one. Try to merge vma after call_mmap() to fix this issue. Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1594954065-23733-1-git-send-email-linmiaohe@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:34 +03:00
unmap_writable:
mm: allow drivers to prevent new writable mappings This patch (of 6): The i_mmap_writable field counts existing writable mappings of an address_space. To allow drivers to prevent new writable mappings, make this counter signed and prevent new writable mappings if it is negative. This is modelled after i_writecount and DENYWRITE. This will be required by the shmem-sealing infrastructure to prevent any new writable mappings after the WRITE seal has been set. In case there exists a writable mapping, this operation will fail with EBUSY. Note that we rely on the fact that iff you already own a writable mapping, you can increase the counter without using the helpers. This is the same that we do for i_writecount. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ryan Lortie <desrt@desrt.ca> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <zonque@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-09 01:25:25 +04:00
if (vm_flags & VM_SHARED)
mapping_unmap_writable(file->f_mapping);
if (vm_flags & VM_DENYWRITE)
allow_write_access(file);
}
mm: mmap_region: kill correct_wcount/inode, use allow_write_access() correct_wcount and inode in mmap_region() just complicate the code. This boolean was needed previously, when deny_write_access() was called before vma_merge(), now we can simply check VM_DENYWRITE and do allow_write_access() if it is set. allow_write_access() checks file != NULL, so this is safe even if it was possible to use VM_DENYWRITE && !file. Just we need to ensure we use the same file which was deny_write_access()'ed, so the patch also moves "file = vma->vm_file" down after allow_write_access(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Colin Cross <ccross@android.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:20:20 +04:00
file = vma->vm_file;
mmap_region: cleanup the final vma_merge() related code It is not easy to actually understand the "if (!file || !vma_merge())" code, turn it into "if (file && vma_merge())". This makes immediately obvious that the subsequent "if (file)" is superfluous. As Hugh Dickins pointed out, we can also factor out the ->i_writecount corrections, and add a small comment about that. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 13:12:10 +04:00
out:
perf: Do the big rename: Performance Counters -> Performance Events Bye-bye Performance Counters, welcome Performance Events! In the past few months the perfcounters subsystem has grown out its initial role of counting hardware events, and has become (and is becoming) a much broader generic event enumeration, reporting, logging, monitoring, analysis facility. Naming its core object 'perf_counter' and naming the subsystem 'perfcounters' has become more and more of a misnomer. With pending code like hw-breakpoints support the 'counter' name is less and less appropriate. All in one, we've decided to rename the subsystem to 'performance events' and to propagate this rename through all fields, variables and API names. (in an ABI compatible fashion) The word 'event' is also a bit shorter than 'counter' - which makes it slightly more convenient to write/handle as well. Thanks goes to Stephane Eranian who first observed this misnomer and suggested a rename. User-space tooling and ABI compatibility is not affected - this patch should be function-invariant. (Also, defconfigs were not touched to keep the size down.) This patch has been generated via the following script: FILES=$(find * -type f | grep -vE 'oprofile|[^K]config') sed -i \ -e 's/PERF_EVENT_/PERF_RECORD_/g' \ -e 's/PERF_COUNTER/PERF_EVENT/g' \ -e 's/perf_counter/perf_event/g' \ -e 's/nb_counters/nb_events/g' \ -e 's/swcounter/swevent/g' \ -e 's/tpcounter_event/tp_event/g' \ $FILES for N in $(find . -name perf_counter.[ch]); do M=$(echo $N | sed 's/perf_counter/perf_event/g') mv $N $M done FILES=$(find . -name perf_event.*) sed -i \ -e 's/COUNTER_MASK/REG_MASK/g' \ -e 's/COUNTER/EVENT/g' \ -e 's/\<event\>/event_id/g' \ -e 's/counter/event/g' \ -e 's/Counter/Event/g' \ $FILES ... to keep it as correct as possible. This script can also be used by anyone who has pending perfcounters patches - it converts a Linux kernel tree over to the new naming. We tried to time this change to the point in time where the amount of pending patches is the smallest: the end of the merge window. Namespace clashes were fixed up in a preparatory patch - and some stylistic fallout will be fixed up in a subsequent patch. ( NOTE: 'counters' are still the proper terminology when we deal with hardware registers - and these sed scripts are a bit over-eager in renaming them. I've undone some of that, but in case there's something left where 'counter' would be better than 'event' we can undo that on an individual basis instead of touching an otherwise nicely automated patch. ) Suggested-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-21 14:02:48 +04:00
perf_event_mmap(vma);
perf_counter: executable mmap() information Currently the profiling information returns userspace IPs but no way to correlate them to userspace code. Userspace could look into /proc/$pid/maps but that might not be current or even present anymore at the time of analyzing the IPs. Therefore provide means to track the mmap information and provide it in the output stream. XXX: only covers mmap()/munmap(), mremap() and mprotect() are missing. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Mackerras <paulus@samba.org> Cc: Andrew Morton <akpm@linux-foundation.org> Orig-LKML-Reference: <20090330171023.417259499@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-30 21:07:05 +04:00
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (vm_flags & VM_LOCKED) {
dax: remove VM_MIXEDMAP for fsdax and device dax This patch is reworked from an earlier patch that Dan has posted: https://patchwork.kernel.org/patch/10131727/ VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that the memory page it is dealing with is not typical memory from the linear map. The get_user_pages_fast() path, since it does not resolve the vma, is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we use that as a VM_MIXEDMAP replacement in some locations. In the cases where there is no pte to consult we fallback to using vma_is_dax() to detect the VM_MIXEDMAP special case. Now that we have explicit driver pfn_t-flag opt-in/opt-out for get_user_pages() support for DAX we can stop setting VM_MIXEDMAP. This also means we no longer need to worry about safely manipulating vm_flags in a future where we support dynamically changing the dax mode of a file. DAX should also now be supported with madvise_behavior(), vma_merge(), and copy_page_range(). This patch has been tested against ndctl unit test. It has also been tested against xfstests commit: 625515d using fake pmem created by memmap and no additional issues have been observed. Link: http://lkml.kernel.org/r/152847720311.55924.16999195879201817653.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-18 01:43:40 +03:00
if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) ||
is_vm_hugetlb_page(vma) ||
vma == get_gate_vma(current->mm))
mm: introduce VM_LOCKONFAULT The cost of faulting in all memory to be locked can be very high when working with large mappings. If only portions of the mapping will be used this can incur a high penalty for locking. For the example of a large file, this is the usage pattern for a large statical language model (probably applies to other statical or graphical models as well). For the security example, any application transacting in data that cannot be swapped out (credit card data, medical records, etc). This patch introduces the ability to request that pages are not pre-faulted, but are placed on the unevictable LRU when they are finally faulted in. The VM_LOCKONFAULT flag will be used together with VM_LOCKED and has no effect when set without VM_LOCKED. Setting the VM_LOCKONFAULT flag for a VMA will cause pages faulted into that VMA to be added to the unevictable LRU when they are faulted or if they are already present, but will not cause any missing pages to be faulted in. Exposing this new lock state means that we cannot overload the meaning of the FOLL_POPULATE flag any longer. Prior to this patch it was used to mean that the VMA for a fault was locked. This means we need the new FOLL_MLOCK flag to communicate the locked state of a VMA. FOLL_POPULATE will now only control if the VMA should be populated and in the case of VM_LOCKONFAULT, it will not be set. Signed-off-by: Eric B Munson <emunson@akamai.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:51:36 +03:00
vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
dax: remove VM_MIXEDMAP for fsdax and device dax This patch is reworked from an earlier patch that Dan has posted: https://patchwork.kernel.org/patch/10131727/ VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that the memory page it is dealing with is not typical memory from the linear map. The get_user_pages_fast() path, since it does not resolve the vma, is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we use that as a VM_MIXEDMAP replacement in some locations. In the cases where there is no pte to consult we fallback to using vma_is_dax() to detect the VM_MIXEDMAP special case. Now that we have explicit driver pfn_t-flag opt-in/opt-out for get_user_pages() support for DAX we can stop setting VM_MIXEDMAP. This also means we no longer need to worry about safely manipulating vm_flags in a future where we support dynamically changing the dax mode of a file. DAX should also now be supported with madvise_behavior(), vma_merge(), and copy_page_range(). This patch has been tested against ndctl unit test. It has also been tested against xfstests commit: 625515d using fake pmem created by memmap and no additional issues have been observed. Link: http://lkml.kernel.org/r/152847720311.55924.16999195879201817653.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-18 01:43:40 +03:00
else
mm->locked_vm += (len >> PAGE_SHIFT);
mm: introduce mm_populate() for populating new vmas When creating new mappings using the MAP_POPULATE / MAP_LOCKED flags (or with MCL_FUTURE in effect), we want to populate the pages within the newly created vmas. This may take a while as we may have to read pages from disk, so ideally we want to do this outside of the write-locked mmap_sem region. This change introduces mm_populate(), which is used to defer populating such mappings until after the mmap_sem write lock has been released. This is implemented as a generalization of the former do_mlock_pages(), which accomplished the same task but was using during mlock() / mlockall(). Signed-off-by: Michel Lespinasse <walken@google.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:37 +04:00
}
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 13:26:42 +04:00
uprobes: Fix mmap_region()'s mm->mm_rb corruption if uprobe_mmap() fails This patch fixes: https://bugzilla.redhat.com/show_bug.cgi?id=843640 If mmap_region()->uprobe_mmap() fails, unmap_and_free_vma path does unmap_region() but does not remove the soon-to-be-freed vma from rb tree. Actually there are more problems but this is how William noticed this bug. Perhaps we could do do_munmap() + return in this case, but in fact it is simply wrong to abort if uprobe_mmap() fails. Until at least we move the !UPROBE_COPY_INSN code from install_breakpoint() to uprobe_register(). For example, uprobe_mmap()->install_breakpoint() can fail if the probed insn is not supported (remember, uprobe_register() succeeds if nobody mmaps inode/offset), mmap() should not fail in this case. dup_mmap()->uprobe_mmap() is wrong too by the same reason, fork() can race with uprobe_register() and fail for no reason if it wins the race and does install_breakpoint() first. And, if nothing else, both mmap_region() and dup_mmap() return success if uprobe_mmap() fails. Change them to ignore the error code from uprobe_mmap(). Reported-and-tested-by: William Cohen <wcohen@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> # v3.5 Cc: Anton Arapov <anton@redhat.com> Cc: William Cohen <wcohen@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120819171042.GB26957@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-08-19 21:10:42 +04:00
if (file)
uprobe_mmap(vma);
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 13:26:42 +04:00
mm: track vma changes with VM_SOFTDIRTY bit Pavel reported that in case if vma area get unmapped and then mapped (or expanded) in-place, the soft dirty tracker won't be able to recognize this situation since it works on pte level and ptes are get zapped on unmap, loosing soft dirty bit of course. So to resolve this situation we need to track actions on vma level, there VM_SOFTDIRTY flag comes in. When new vma area created (or old expanded) we set this bit, and keep it here until application calls for clearing soft dirty bit. Thus when user space application track memory changes now it can detect if vma area is renewed. Reported-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Matt Mackall <mpm@selenic.com> Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:22:24 +04:00
/*
* New (or expanded) vma always get soft dirty status.
* Otherwise user-space soft-dirty page tracker won't
* be able to distinguish situation when vma area unmapped,
* then new mapped in-place (which must be aimed as
* a completely new data area).
*/
vma->vm_flags |= VM_SOFTDIRTY;
mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:55:46 +04:00
vma_set_page_prot(vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return addr;
unmap_and_free_vma:
vma->vm_file = NULL;
fput(file);
/* Undo any partial mapping done by a device driver. */
[PATCH] freepgt: free_pgtables use vma list Recent woes with some arches needing their own pgd_addr_end macro; and 4-level clear_page_range regression since 2.6.10's clear_page_tables; and its long-standing well-known inefficiency in searching throughout the higher-level page tables for those few entries to clear and free: all can be blamed on ignoring the list of vmas when we free page tables. Replace exit_mmap's clear_page_range of the total user address space by free_pgtables operating on the mm's vma list; unmap_region use it in the same way, giving floor and ceiling beyond which it may not free tables. This brings lmbench fork/exec/sh numbers back to 2.6.10 (unless preempt is enabled, in which case latency fixes spoil unmap_vmas throughput). Beware: the do_mmap_pgoff driver failure case must now use unmap_region instead of zap_page_range, since a page table might have been allocated, and can only be freed while it is touched by some vma. Move free_pgtables from mmap.c to memory.c, where its lower levels are adapted from the clear_page_range levels. (Most of free_pgtables' old code was actually for a non-existent case, prev not properly set up, dating from before hch gave us split_vma.) Pass mmu_gather** in the public interfaces, since we might want to add latency lockdrops later; but no attempt to do so yet, going by vma should itself reduce latency. But what if is_hugepage_only_range? Those ia64 and ppc64 cases need careful examination: put that off until a later patch of the series. What of x86_64's 32bit vdso page __map_syscall32 maps outside any vma? And the range to sparc64's flush_tlb_pgtables? It's less clear to me now that we need to do more than is done here - every PMD_SIZE ever occupied will be flushed, do we really have to flush every PGDIR_SIZE ever partially occupied? A shame to complicate it unnecessarily. Special thanks to David Miller for time spent repairing my ceilings. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:15 +04:00
unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
charged = 0;
mm: allow drivers to prevent new writable mappings This patch (of 6): The i_mmap_writable field counts existing writable mappings of an address_space. To allow drivers to prevent new writable mappings, make this counter signed and prevent new writable mappings if it is negative. This is modelled after i_writecount and DENYWRITE. This will be required by the shmem-sealing infrastructure to prevent any new writable mappings after the WRITE seal has been set. In case there exists a writable mapping, this operation will fail with EBUSY. Note that we rely on the fact that iff you already own a writable mapping, you can increase the counter without using the helpers. This is the same that we do for i_writecount. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ryan Lortie <desrt@desrt.ca> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <zonque@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-09 01:25:25 +04:00
if (vm_flags & VM_SHARED)
mapping_unmap_writable(file->f_mapping);
allow_write_and_free_vma:
if (vm_flags & VM_DENYWRITE)
allow_write_access(file);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
free_vma:
mm: use helper functions for allocating and freeing vm_area structs The vm_area_struct is one of the most fundamental memory management objects, but the management of it is entirely open-coded evertwhere, ranging from allocation and freeing (using kmem_cache_[z]alloc and kmem_cache_free) to initializing all the fields. We want to unify this in order to end up having some unified initialization of the vmas, and the first step to this is to at least have basic allocation functions. Right now those functions are literally just wrappers around the kmem_cache_*() calls. This is a purely mechanical conversion: # new vma: kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc() # copy old vma kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old) # free vma kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma) to the point where the old vma passed in to the vm_area_dup() function isn't even used yet (because I've left all the old manual initialization alone). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-21 23:48:51 +03:00
vm_area_free(vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
unacct_error:
if (charged)
vm_unacct_memory(charged);
return error;
}
mmap: remove inline of vm_unmapped_area Patch series "mm: mmap: add mmap trace point", v3. Create mmap trace file and add trace point of vm_unmapped_area(). This patch (of 2): In preparation for next patch remove inline of vm_unmapped_area and move code to mmap.c. There is no logical change. Also remove unmapped_area[_topdown] out of mm.h, there is no code calling to them. Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200320055823.27089-2-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:10 +03:00
static unsigned long unmapped_area(struct vm_unmapped_area_info *info)
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
{
/*
* We implement the search by looking for an rbtree node that
* immediately follows a suitable gap. That is,
* - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
* - gap_end = vma->vm_start >= info->low_limit + length;
* - gap_end - gap_start >= length
*/
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long length, low_limit, high_limit, gap_start, gap_end;
/* Adjust search length to account for worst case alignment overhead */
length = info->length + info->align_mask;
if (length < info->length)
return -ENOMEM;
/* Adjust search limits by the desired length */
if (info->high_limit < length)
return -ENOMEM;
high_limit = info->high_limit - length;
if (info->low_limit > high_limit)
return -ENOMEM;
low_limit = info->low_limit + length;
/* Check if rbtree root looks promising */
if (RB_EMPTY_ROOT(&mm->mm_rb))
goto check_highest;
vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
if (vma->rb_subtree_gap < length)
goto check_highest;
while (true) {
/* Visit left subtree if it looks promising */
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
gap_end = vm_start_gap(vma);
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
if (gap_end >= low_limit && vma->vm_rb.rb_left) {
struct vm_area_struct *left =
rb_entry(vma->vm_rb.rb_left,
struct vm_area_struct, vm_rb);
if (left->rb_subtree_gap >= length) {
vma = left;
continue;
}
}
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
check_current:
/* Check if current node has a suitable gap */
if (gap_start > high_limit)
return -ENOMEM;
mm: fix new crash in unmapped_area_topdown() Trinity gets kernel BUG at mm/mmap.c:1963! in about 3 minutes of mmap testing. That's the VM_BUG_ON(gap_end < gap_start) at the end of unmapped_area_topdown(). Linus points out how MAP_FIXED (which does not have to respect our stack guard gap intentions) could result in gap_end below gap_start there. Fix that, and the similar case in its alternative, unmapped_area(). Cc: stable@vger.kernel.org Fixes: 1be7107fbe18 ("mm: larger stack guard gap, between vmas") Reported-by: Dave Jones <davej@codemonkey.org.uk> Debugged-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-20 12:10:44 +03:00
if (gap_end >= low_limit &&
gap_end > gap_start && gap_end - gap_start >= length)
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
goto found;
/* Visit right subtree if it looks promising */
if (vma->vm_rb.rb_right) {
struct vm_area_struct *right =
rb_entry(vma->vm_rb.rb_right,
struct vm_area_struct, vm_rb);
if (right->rb_subtree_gap >= length) {
vma = right;
continue;
}
}
/* Go back up the rbtree to find next candidate node */
while (true) {
struct rb_node *prev = &vma->vm_rb;
if (!rb_parent(prev))
goto check_highest;
vma = rb_entry(rb_parent(prev),
struct vm_area_struct, vm_rb);
if (prev == vma->vm_rb.rb_left) {
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
gap_start = vm_end_gap(vma->vm_prev);
gap_end = vm_start_gap(vma);
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
goto check_current;
}
}
}
check_highest:
/* Check highest gap, which does not precede any rbtree node */
gap_start = mm->highest_vm_end;
gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */
if (gap_start > high_limit)
return -ENOMEM;
found:
/* We found a suitable gap. Clip it with the original low_limit. */
if (gap_start < info->low_limit)
gap_start = info->low_limit;
/* Adjust gap address to the desired alignment */
gap_start += (info->align_offset - gap_start) & info->align_mask;
VM_BUG_ON(gap_start + info->length > info->high_limit);
VM_BUG_ON(gap_start + info->length > gap_end);
return gap_start;
}
mmap: remove inline of vm_unmapped_area Patch series "mm: mmap: add mmap trace point", v3. Create mmap trace file and add trace point of vm_unmapped_area(). This patch (of 2): In preparation for next patch remove inline of vm_unmapped_area and move code to mmap.c. There is no logical change. Also remove unmapped_area[_topdown] out of mm.h, there is no code calling to them. Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200320055823.27089-2-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:10 +03:00
static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long length, low_limit, high_limit, gap_start, gap_end;
/* Adjust search length to account for worst case alignment overhead */
length = info->length + info->align_mask;
if (length < info->length)
return -ENOMEM;
/*
* Adjust search limits by the desired length.
* See implementation comment at top of unmapped_area().
*/
gap_end = info->high_limit;
if (gap_end < length)
return -ENOMEM;
high_limit = gap_end - length;
if (info->low_limit > high_limit)
return -ENOMEM;
low_limit = info->low_limit + length;
/* Check highest gap, which does not precede any rbtree node */
gap_start = mm->highest_vm_end;
if (gap_start <= high_limit)
goto found_highest;
/* Check if rbtree root looks promising */
if (RB_EMPTY_ROOT(&mm->mm_rb))
return -ENOMEM;
vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
if (vma->rb_subtree_gap < length)
return -ENOMEM;
while (true) {
/* Visit right subtree if it looks promising */
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
if (gap_start <= high_limit && vma->vm_rb.rb_right) {
struct vm_area_struct *right =
rb_entry(vma->vm_rb.rb_right,
struct vm_area_struct, vm_rb);
if (right->rb_subtree_gap >= length) {
vma = right;
continue;
}
}
check_current:
/* Check if current node has a suitable gap */
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
gap_end = vm_start_gap(vma);
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
if (gap_end < low_limit)
return -ENOMEM;
mm: fix new crash in unmapped_area_topdown() Trinity gets kernel BUG at mm/mmap.c:1963! in about 3 minutes of mmap testing. That's the VM_BUG_ON(gap_end < gap_start) at the end of unmapped_area_topdown(). Linus points out how MAP_FIXED (which does not have to respect our stack guard gap intentions) could result in gap_end below gap_start there. Fix that, and the similar case in its alternative, unmapped_area(). Cc: stable@vger.kernel.org Fixes: 1be7107fbe18 ("mm: larger stack guard gap, between vmas") Reported-by: Dave Jones <davej@codemonkey.org.uk> Debugged-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-20 12:10:44 +03:00
if (gap_start <= high_limit &&
gap_end > gap_start && gap_end - gap_start >= length)
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
goto found;
/* Visit left subtree if it looks promising */
if (vma->vm_rb.rb_left) {
struct vm_area_struct *left =
rb_entry(vma->vm_rb.rb_left,
struct vm_area_struct, vm_rb);
if (left->rb_subtree_gap >= length) {
vma = left;
continue;
}
}
/* Go back up the rbtree to find next candidate node */
while (true) {
struct rb_node *prev = &vma->vm_rb;
if (!rb_parent(prev))
return -ENOMEM;
vma = rb_entry(rb_parent(prev),
struct vm_area_struct, vm_rb);
if (prev == vma->vm_rb.rb_right) {
gap_start = vma->vm_prev ?
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
vm_end_gap(vma->vm_prev) : 0;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
goto check_current;
}
}
}
found:
/* We found a suitable gap. Clip it with the original high_limit. */
if (gap_end > info->high_limit)
gap_end = info->high_limit;
found_highest:
/* Compute highest gap address at the desired alignment */
gap_end -= info->length;
gap_end -= (gap_end - info->align_offset) & info->align_mask;
VM_BUG_ON(gap_end < info->low_limit);
VM_BUG_ON(gap_end < gap_start);
return gap_end;
}
mmap: remove inline of vm_unmapped_area Patch series "mm: mmap: add mmap trace point", v3. Create mmap trace file and add trace point of vm_unmapped_area(). This patch (of 2): In preparation for next patch remove inline of vm_unmapped_area and move code to mmap.c. There is no logical change. Also remove unmapped_area[_topdown] out of mm.h, there is no code calling to them. Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200320055823.27089-2-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:10 +03:00
/*
* Search for an unmapped address range.
*
* We are looking for a range that:
* - does not intersect with any VMA;
* - is contained within the [low_limit, high_limit) interval;
* - is at least the desired size.
* - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
*/
unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info)
{
mm: mmap: add trace point of vm_unmapped_area Even on 64 bit kernel, the mmap failure can happen for a 32 bit task. Virtual memory space shortage of a task on mmap is reported to userspace as -ENOMEM. It can be confused as physical memory shortage of overall system. The vm_unmapped_area can be called to by some drivers or other kernel core system like filesystem. In my platform, GPU driver calls to vm_unmapped_area and the driver returns -ENOMEM even in GPU side shortage. It can be hard to distinguish which code layer returns the -ENOMEM. Create mmap trace file and add trace point of vm_unmapped_area. i.e.) 277.156599: vm_unmapped_area: addr=77e0d03000 err=0 total_vm=0x17014b flags=0x1 len=0x400000 lo=0x8000 hi=0x7878c27000 mask=0x0 ofs=0x1 342.838740: vm_unmapped_area: addr=0 err=-12 total_vm=0xffb08 flags=0x0 len=0x100000 lo=0x40000000 hi=0xfffff000 mask=0x0 ofs=0x22 [akpm@linux-foundation.org: prefix address printk with 0x, per Matthew] Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200320055823.27089-3-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:13 +03:00
unsigned long addr;
mmap: remove inline of vm_unmapped_area Patch series "mm: mmap: add mmap trace point", v3. Create mmap trace file and add trace point of vm_unmapped_area(). This patch (of 2): In preparation for next patch remove inline of vm_unmapped_area and move code to mmap.c. There is no logical change. Also remove unmapped_area[_topdown] out of mm.h, there is no code calling to them. Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200320055823.27089-2-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:10 +03:00
if (info->flags & VM_UNMAPPED_AREA_TOPDOWN)
mm: mmap: add trace point of vm_unmapped_area Even on 64 bit kernel, the mmap failure can happen for a 32 bit task. Virtual memory space shortage of a task on mmap is reported to userspace as -ENOMEM. It can be confused as physical memory shortage of overall system. The vm_unmapped_area can be called to by some drivers or other kernel core system like filesystem. In my platform, GPU driver calls to vm_unmapped_area and the driver returns -ENOMEM even in GPU side shortage. It can be hard to distinguish which code layer returns the -ENOMEM. Create mmap trace file and add trace point of vm_unmapped_area. i.e.) 277.156599: vm_unmapped_area: addr=77e0d03000 err=0 total_vm=0x17014b flags=0x1 len=0x400000 lo=0x8000 hi=0x7878c27000 mask=0x0 ofs=0x1 342.838740: vm_unmapped_area: addr=0 err=-12 total_vm=0xffb08 flags=0x0 len=0x100000 lo=0x40000000 hi=0xfffff000 mask=0x0 ofs=0x22 [akpm@linux-foundation.org: prefix address printk with 0x, per Matthew] Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200320055823.27089-3-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:13 +03:00
addr = unmapped_area_topdown(info);
mmap: remove inline of vm_unmapped_area Patch series "mm: mmap: add mmap trace point", v3. Create mmap trace file and add trace point of vm_unmapped_area(). This patch (of 2): In preparation for next patch remove inline of vm_unmapped_area and move code to mmap.c. There is no logical change. Also remove unmapped_area[_topdown] out of mm.h, there is no code calling to them. Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200320055823.27089-2-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:10 +03:00
else
mm: mmap: add trace point of vm_unmapped_area Even on 64 bit kernel, the mmap failure can happen for a 32 bit task. Virtual memory space shortage of a task on mmap is reported to userspace as -ENOMEM. It can be confused as physical memory shortage of overall system. The vm_unmapped_area can be called to by some drivers or other kernel core system like filesystem. In my platform, GPU driver calls to vm_unmapped_area and the driver returns -ENOMEM even in GPU side shortage. It can be hard to distinguish which code layer returns the -ENOMEM. Create mmap trace file and add trace point of vm_unmapped_area. i.e.) 277.156599: vm_unmapped_area: addr=77e0d03000 err=0 total_vm=0x17014b flags=0x1 len=0x400000 lo=0x8000 hi=0x7878c27000 mask=0x0 ofs=0x1 342.838740: vm_unmapped_area: addr=0 err=-12 total_vm=0xffb08 flags=0x0 len=0x100000 lo=0x40000000 hi=0xfffff000 mask=0x0 ofs=0x22 [akpm@linux-foundation.org: prefix address printk with 0x, per Matthew] Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200320055823.27089-3-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:13 +03:00
addr = unmapped_area(info);
trace_vm_unmapped_area(addr, info);
return addr;
mmap: remove inline of vm_unmapped_area Patch series "mm: mmap: add mmap trace point", v3. Create mmap trace file and add trace point of vm_unmapped_area(). This patch (of 2): In preparation for next patch remove inline of vm_unmapped_area and move code to mmap.c. There is no logical change. Also remove unmapped_area[_topdown] out of mm.h, there is no code calling to them. Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200320055823.27089-2-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 07:09:10 +03:00
}
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
#ifndef arch_get_mmap_end
#define arch_get_mmap_end(addr) (TASK_SIZE)
#endif
#ifndef arch_get_mmap_base
#define arch_get_mmap_base(addr, base) (base)
#endif
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Get an address range which is currently unmapped.
* For shmat() with addr=0.
*
* Ugly calling convention alert:
* Return value with the low bits set means error value,
* ie
* if (ret & ~PAGE_MASK)
* error = ret;
*
* This function "knows" that -ENOMEM has the bits set.
*/
#ifndef HAVE_ARCH_UNMAPPED_AREA
unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
struct vm_area_struct *vma, *prev;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
struct vm_unmapped_area_info info;
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
const unsigned long mmap_end = arch_get_mmap_end(addr);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
if (len > mmap_end - mmap_min_addr)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -ENOMEM;
get_unmapped_area handles MAP_FIXED in generic code generic arch_get_unmapped_area() now handles MAP_FIXED. Now that all implementations have been fixed, change the toplevel get_unmapped_area() to call into arch or drivers for the MAP_FIXED case. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: William Irwin <bill.irwin@oracle.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 01:50:13 +04:00
if (flags & MAP_FIXED)
return addr;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (addr) {
addr = PAGE_ALIGN(addr);
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
vma = find_vma_prev(mm, addr, &prev);
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
if (mmap_end - len >= addr && addr >= mmap_min_addr &&
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
(!vma || addr + len <= vm_start_gap(vma)) &&
(!prev || addr >= vm_end_gap(prev)))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return addr;
}
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
info.flags = 0;
info.length = len;
mmap: arch_get_unmapped_area(): use proper mmap base for bottom up direction This is more or less the generic variant of commit 41aacc1eea64 ("x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member"). So effectively architectures which use an own arch_pick_mmap_layout() implementation but call the generic arch_get_unmapped_area() now can also randomize their mmap_base. All architectures which have an own arch_pick_mmap_layout() and call the generic arch_get_unmapped_area() (arm64, s390, tile) currently set mmap_base to TASK_UNMAPPED_BASE. This is also true for the generic arch_pick_mmap_layout() function. So this change is a no-op currently. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Radu Caragea <sinaelgl@gmail.com> Cc: Michel Lespinasse <walken@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 03:07:54 +04:00
info.low_limit = mm->mmap_base;
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
info.high_limit = mmap_end;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
info.align_mask = 0;
mm/mmap.c: initialize align_offset explicitly for vm_unmapped_area On passing requirement to vm_unmapped_area, arch_get_unmapped_area and arch_get_unmapped_area_topdown did not set align_offset. Internally on both unmapped_area and unmapped_area_topdown, if info->align_mask is 0, then info->align_offset was meaningless. But commit df529cabb7a2 ("mm: mmap: add trace point of vm_unmapped_area") always prints info->align_offset even though it is uninitialized. Fix this uninitialized value issue by setting it to 0 explicitly. Before: vm_unmapped_area: addr=0x755b155000 err=0 total_vm=0x15aaf0 flags=0x1 len=0x109000 lo=0x8000 hi=0x75eed48000 mask=0x0 ofs=0x4022 After: vm_unmapped_area: addr=0x74a4ca1000 err=0 total_vm=0x168ab1 flags=0x1 len=0x9000 lo=0x8000 hi=0x753d94b000 mask=0x0 ofs=0x0 Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200409094035.19457-1-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-11 00:32:48 +03:00
info.align_offset = 0;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
return vm_unmapped_area(&info);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
#endif
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* This mmap-allocator allocates new areas top-down from below the
* stack's low limit (the base):
*/
#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
unsigned long
mm/mmap.c: remove some redundancy in arch_get_unmapped_area_topdown() The variable 'addr' is redundant in arch_get_unmapped_area_topdown(), just use parameter 'addr0' directly. Then remove the const qualifier of the parameter, and change its name to 'addr'. And in according with other functions, remove the const qualifier of all other no-pointer parameters in function arch_get_unmapped_area_topdown(). Link: http://lkml.kernel.org/r/20190127041112.25599-1-nullptr.cpp@gmail.com Signed-off-by: Yang Fan <nullptr.cpp@gmail.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Cc: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-06 02:46:16 +03:00
arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
struct vm_area_struct *vma, *prev;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
struct mm_struct *mm = current->mm;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
struct vm_unmapped_area_info info;
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
const unsigned long mmap_end = arch_get_mmap_end(addr);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* requested length too big for entire address space */
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
if (len > mmap_end - mmap_min_addr)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -ENOMEM;
get_unmapped_area handles MAP_FIXED in generic code generic arch_get_unmapped_area() now handles MAP_FIXED. Now that all implementations have been fixed, change the toplevel get_unmapped_area() to call into arch or drivers for the MAP_FIXED case. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: William Irwin <bill.irwin@oracle.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 01:50:13 +04:00
if (flags & MAP_FIXED)
return addr;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* requesting a specific address */
if (addr) {
addr = PAGE_ALIGN(addr);
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
vma = find_vma_prev(mm, addr, &prev);
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
if (mmap_end - len >= addr && addr >= mmap_min_addr &&
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
(!vma || addr + len <= vm_start_gap(vma)) &&
(!prev || addr >= vm_end_gap(prev)))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return addr;
}
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
mm: ensure get_unmapped_area() returns higher address than mmap_min_addr This patch fixes the problem that get_unmapped_area() can return illegal address and result in failing mmap(2) etc. In case that the address higher than PAGE_SIZE is set to /proc/sys/vm/mmap_min_addr, the address lower than mmap_min_addr can be returned by get_unmapped_area(), even if you do not pass any virtual address hint (i.e. the second argument). This is because the current get_unmapped_area() code does not take into account mmap_min_addr. This leads to two actual problems as follows: 1. mmap(2) can fail with EPERM on the process without CAP_SYS_RAWIO, although any illegal parameter is not passed. 2. The bottom-up search path after the top-down search might not work in arch_get_unmapped_area_topdown(). Note: The first and third chunk of my patch, which changes "len" check, are for more precise check using mmap_min_addr, and not for solving the above problem. [How to reproduce] --- test.c ------------------------------------------------- #include <stdio.h> #include <unistd.h> #include <sys/mman.h> #include <sys/errno.h> int main(int argc, char *argv[]) { void *ret = NULL, *last_map; size_t pagesize = sysconf(_SC_PAGESIZE); do { last_map = ret; ret = mmap(0, pagesize, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); // printf("ret=%p\n", ret); } while (ret != MAP_FAILED); if (errno != ENOMEM) { printf("ERR: unexpected errno: %d (last map=%p)\n", errno, last_map); } return 0; } --------------------------------------------------------------- $ gcc -m32 -o test test.c $ sudo sysctl -w vm.mmap_min_addr=65536 vm.mmap_min_addr = 65536 $ ./test (run as non-priviledge user) ERR: unexpected errno: 1 (last map=0x10000) Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com> Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 03:08:21 +04:00
info.low_limit = max(PAGE_SIZE, mmap_min_addr);
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
info.high_limit = arch_get_mmap_base(addr, mm->mmap_base);
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
info.align_mask = 0;
mm/mmap.c: initialize align_offset explicitly for vm_unmapped_area On passing requirement to vm_unmapped_area, arch_get_unmapped_area and arch_get_unmapped_area_topdown did not set align_offset. Internally on both unmapped_area and unmapped_area_topdown, if info->align_mask is 0, then info->align_offset was meaningless. But commit df529cabb7a2 ("mm: mmap: add trace point of vm_unmapped_area") always prints info->align_offset even though it is uninitialized. Fix this uninitialized value issue by setting it to 0 explicitly. Before: vm_unmapped_area: addr=0x755b155000 err=0 total_vm=0x15aaf0 flags=0x1 len=0x109000 lo=0x8000 hi=0x75eed48000 mask=0x0 ofs=0x4022 After: vm_unmapped_area: addr=0x74a4ca1000 err=0 total_vm=0x168ab1 flags=0x1 len=0x9000 lo=0x8000 hi=0x753d94b000 mask=0x0 ofs=0x0 Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200409094035.19457-1-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-11 00:32:48 +03:00
info.align_offset = 0;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
addr = vm_unmapped_area(&info);
mm: search from free_area_cache for the bigger size If the required size is bigger than cached_hole_size it is better to search from free_area_cache - it is easier to get a free region, specifically for the 64 bit process whose address space is large enough Do it just as hugetlb_get_unmapped_area_topdown() in arch/x86/mm/hugetlbpage.c Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hillf Danton <dhillf@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-22 03:33:56 +04:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
mm/mmap: use offset_in_page macro linux/mm.h provides offset_in_page() macro. Let's use already predefined macro instead of (addr & ~PAGE_MASK). Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:46:54 +03:00
if (offset_in_page(addr)) {
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
VM_BUG_ON(addr != -ENOMEM);
info.flags = 0;
info.low_limit = TASK_UNMAPPED_BASE;
mm: mmap: Allow for "high" userspace addresses This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of arch_get_unmapped_* functions. However, on arm64 we use the generic versions of these functions. Rather than duplicate the generic arch_get_unmapped_* implementations for arm64, this patch instead introduces two architectural helper macros and applies them to arch_get_unmapped_*: arch_get_mmap_end(addr) - get mmap upper limit depending on addr hint arch_get_mmap_base(addr, base) - get mmap_base depending on addr hint If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 01:50:36 +03:00
info.high_limit = mmap_end;
mm: vm_unmapped_area() lookup function Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end information to look up for suitable virtual address space gaps. struct vm_unmapped_area_info is used to define the desired allocation request: - lowest or highest possible address matching the remaining constraints - desired gap length - low/high address limits that the gap must fit into - alignment mask and offset Also update the generic arch_get_unmapped_area[_topdown] functions to make use of vm_unmapped_area() instead of implementing a brute force search. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:49 +04:00
addr = vm_unmapped_area(&info);
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return addr;
}
#endif
unsigned long
get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
get_unmapped_area handles MAP_FIXED in generic code generic arch_get_unmapped_area() now handles MAP_FIXED. Now that all implementations have been fixed, change the toplevel get_unmapped_area() to call into arch or drivers for the MAP_FIXED case. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: William Irwin <bill.irwin@oracle.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 01:50:13 +04:00
unsigned long (*get_area)(struct file *, unsigned long,
unsigned long, unsigned long, unsigned long);
Take arch_mmap_check() into get_unmapped_area() Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-03 23:23:11 +03:00
unsigned long error = arch_mmap_check(addr, len, flags);
if (error)
return error;
/* Careful about overflows.. */
if (len > TASK_SIZE)
return -ENOMEM;
get_unmapped_area handles MAP_FIXED in generic code generic arch_get_unmapped_area() now handles MAP_FIXED. Now that all implementations have been fixed, change the toplevel get_unmapped_area() to call into arch or drivers for the MAP_FIXED case. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: William Irwin <bill.irwin@oracle.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 01:50:13 +04:00
get_area = current->mm->get_unmapped_area;
shmem: get_unmapped_area align huge page Provide a shmem_get_unmapped_area method in file_operations, called at mmap time to decide the mapping address. It could be conditional on CONFIG_TRANSPARENT_HUGEPAGE, but save #ifdefs in other places by making it unconditional. shmem_get_unmapped_area() first calls the usual mm->get_unmapped_area (which we treat as a black box, highly dependent on architecture and config and executable layout). Lots of conditions, and in most cases it just goes with the address that chose; but when our huge stars are rightly aligned, yet that did not provide a suitable address, go back to ask for a larger arena, within which to align the mapping suitably. There have to be some direct calls to shmem_get_unmapped_area(), not via the file_operations: because of the way shmem_zero_setup() is called to create a shmem object late in the mmap sequence, when MAP_SHARED is requested with MAP_ANONYMOUS or /dev/zero. Though this only matters when /proc/sys/vm/shmem_huge has been set. Link: http://lkml.kernel.org/r/1466021202-61880-29-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27 01:26:15 +03:00
if (file) {
if (file->f_op->get_unmapped_area)
get_area = file->f_op->get_unmapped_area;
} else if (flags & MAP_SHARED) {
/*
* mmap_region() will call shmem_zero_setup() to create a file,
* so use shmem's get_unmapped_area in case it can be huge.
mm: remove unnecessary wrapper function do_mmap_pgoff() The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db7f82 ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:37 +03:00
* do_mmap() will clear pgoff, so match alignment.
shmem: get_unmapped_area align huge page Provide a shmem_get_unmapped_area method in file_operations, called at mmap time to decide the mapping address. It could be conditional on CONFIG_TRANSPARENT_HUGEPAGE, but save #ifdefs in other places by making it unconditional. shmem_get_unmapped_area() first calls the usual mm->get_unmapped_area (which we treat as a black box, highly dependent on architecture and config and executable layout). Lots of conditions, and in most cases it just goes with the address that chose; but when our huge stars are rightly aligned, yet that did not provide a suitable address, go back to ask for a larger arena, within which to align the mapping suitably. There have to be some direct calls to shmem_get_unmapped_area(), not via the file_operations: because of the way shmem_zero_setup() is called to create a shmem object late in the mmap sequence, when MAP_SHARED is requested with MAP_ANONYMOUS or /dev/zero. Though this only matters when /proc/sys/vm/shmem_huge has been set. Link: http://lkml.kernel.org/r/1466021202-61880-29-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27 01:26:15 +03:00
*/
pgoff = 0;
get_area = shmem_get_unmapped_area;
}
get_unmapped_area handles MAP_FIXED in generic code generic arch_get_unmapped_area() now handles MAP_FIXED. Now that all implementations have been fixed, change the toplevel get_unmapped_area() to call into arch or drivers for the MAP_FIXED case. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: William Irwin <bill.irwin@oracle.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 01:50:13 +04:00
addr = get_area(file, addr, len, pgoff, flags);
if (IS_ERR_VALUE(addr))
return addr;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
Fix get_unmapped_area sanity tests As noted by Chris Wright, we need to do the full range of tests regardless of whether MAP_FIXED is set or not, so re-organize get_unmapped_area() slightly to do the sanity checks unconditionally.
2005-05-20 09:43:37 +04:00
if (addr > TASK_SIZE - len)
return -ENOMEM;
mm/mmap: use offset_in_page macro linux/mm.h provides offset_in_page() macro. Let's use already predefined macro instead of (addr & ~PAGE_MASK). Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:46:54 +03:00
if (offset_in_page(addr))
Fix get_unmapped_area sanity tests As noted by Chris Wright, we need to do the full range of tests regardless of whether MAP_FIXED is set or not, so re-organize get_unmapped_area() slightly to do the sanity checks unconditionally.
2005-05-20 09:43:37 +04:00
return -EINVAL;
get_unmapped_area handles MAP_FIXED in generic code generic arch_get_unmapped_area() now handles MAP_FIXED. Now that all implementations have been fixed, change the toplevel get_unmapped_area() to call into arch or drivers for the MAP_FIXED case. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: William Irwin <bill.irwin@oracle.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 01:50:13 +04:00
move security_mmap_addr() to saner place it really should be done by get_unmapped_area(); that cuts down on the amount of callers considerably and it's the right place for that stuff anyway. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-31 01:13:15 +04:00
error = security_mmap_addr(addr);
return error ? error : addr;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
EXPORT_SYMBOL(get_unmapped_area);
/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
mm/mmap.c: fix coding style Fix a little of the coding style in mm/mmap.c [akpm@linux-foundation.org: cleanup] Signed-off-by: ZhenwenXu <helight.xu@gmail.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-07 01:40:21 +03:00
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm: per-thread vma caching This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 02:37:25 +04:00
struct rb_node *rb_node;
struct vm_area_struct *vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm/mmap.c: find_vma(): remove unnecessary if(mm) check The "if (mm)" check is not required in find_vma, as the kernel code calls find_vma only when it is absolutely sure that the mm_struct arg to it is non-NULL. Remove the if(mm) check and adding the a WARN_ONCE(!mm) for now. This will serve the purpose of mandating that the execution context(user-mode/kernel-mode) be known before find_vma is called. Also fixed 2 checkpatch.pl errors in the declaration of the rb_node and vma_tmp local variables. I was browsing through the internet and read a discussion at https://lkml.org/lkml/2012/3/27/342 which discusses removal of the validation check within find_vma. Since no-one responded, I decided to send this patch with Andrew's suggestions. [akpm@linux-foundation.org: add remove-me comment] Signed-off-by: Rajman Mekaco <rajman.mekaco@gmail.com> Cc: Kautuk Consul <consul.kautuk@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-30 02:06:21 +04:00
/* Check the cache first. */
mm: per-thread vma caching This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 02:37:25 +04:00
vma = vmacache_find(mm, addr);
if (likely(vma))
return vma;
mm/mmap.c: find_vma(): remove unnecessary if(mm) check The "if (mm)" check is not required in find_vma, as the kernel code calls find_vma only when it is absolutely sure that the mm_struct arg to it is non-NULL. Remove the if(mm) check and adding the a WARN_ONCE(!mm) for now. This will serve the purpose of mandating that the execution context(user-mode/kernel-mode) be known before find_vma is called. Also fixed 2 checkpatch.pl errors in the declaration of the rb_node and vma_tmp local variables. I was browsing through the internet and read a discussion at https://lkml.org/lkml/2012/3/27/342 which discusses removal of the validation check within find_vma. Since no-one responded, I decided to send this patch with Andrew's suggestions. [akpm@linux-foundation.org: add remove-me comment] Signed-off-by: Rajman Mekaco <rajman.mekaco@gmail.com> Cc: Kautuk Consul <consul.kautuk@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-30 02:06:21 +04:00
mm: per-thread vma caching This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 02:37:25 +04:00
rb_node = mm->mm_rb.rb_node;
mm/mmap.c: find_vma(): remove unnecessary if(mm) check The "if (mm)" check is not required in find_vma, as the kernel code calls find_vma only when it is absolutely sure that the mm_struct arg to it is non-NULL. Remove the if(mm) check and adding the a WARN_ONCE(!mm) for now. This will serve the purpose of mandating that the execution context(user-mode/kernel-mode) be known before find_vma is called. Also fixed 2 checkpatch.pl errors in the declaration of the rb_node and vma_tmp local variables. I was browsing through the internet and read a discussion at https://lkml.org/lkml/2012/3/27/342 which discusses removal of the validation check within find_vma. Since no-one responded, I decided to send this patch with Andrew's suggestions. [akpm@linux-foundation.org: add remove-me comment] Signed-off-by: Rajman Mekaco <rajman.mekaco@gmail.com> Cc: Kautuk Consul <consul.kautuk@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-30 02:06:21 +04:00
mm: per-thread vma caching This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 02:37:25 +04:00
while (rb_node) {
struct vm_area_struct *tmp;
tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
if (tmp->vm_end > addr) {
vma = tmp;
if (tmp->vm_start <= addr)
break;
rb_node = rb_node->rb_left;
} else
rb_node = rb_node->rb_right;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: per-thread vma caching This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 02:37:25 +04:00
if (vma)
vmacache_update(addr, vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return vma;
}
EXPORT_SYMBOL(find_vma);
mm: simplify find_vma_prev() commit 297c5eee37 ("mm: make the vma list be doubly linked") added the vm_prev member to vm_area_struct. We can simplify find_vma_prev() by using it. Also, this change helps to improve page fault performance because it has stronger locality of reference. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-11 03:08:07 +04:00
/*
* Same as find_vma, but also return a pointer to the previous VMA in *pprev.
*/
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
struct vm_area_struct *
find_vma_prev(struct mm_struct *mm, unsigned long addr,
struct vm_area_struct **pprev)
{
mm: simplify find_vma_prev() commit 297c5eee37 ("mm: make the vma list be doubly linked") added the vm_prev member to vm_area_struct. We can simplify find_vma_prev() by using it. Also, this change helps to improve page fault performance because it has stronger locality of reference. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-11 03:08:07 +04:00
struct vm_area_struct *vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: simplify find_vma_prev() commit 297c5eee37 ("mm: make the vma list be doubly linked") added the vm_prev member to vm_area_struct. We can simplify find_vma_prev() by using it. Also, this change helps to improve page fault performance because it has stronger locality of reference. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-11 03:08:07 +04:00
vma = find_vma(mm, addr);
mm: fix find_vma_prev Commit 6bd4837de96e ("mm: simplify find_vma_prev()") broke memory management on PA-RISC. After application of the patch, programs that allocate big arrays on the stack crash with segfault, for example, this will crash if compiled without optimization: int main() { char array[200000]; array[199999] = 0; return 0; } The reason is that PA-RISC has up-growing stack and the stack is usually the last memory area. In the above example, a page fault happens above the stack. Previously, if we passed too high address to find_vma_prev, it returned NULL and stored the last VMA in *pprev. After "simplify find_vma_prev" change, it stores NULL in *pprev. Consequently, the stack area is not found and it is not expanded, as it used to be before the change. This patch restores the old behavior and makes it return the last VMA in *pprev if the requested address is higher than address of any other VMA. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 04:52:03 +04:00
if (vma) {
*pprev = vma->vm_prev;
} else {
mm/mmap.c: refine find_vma_prev() with rb_last() When addr is out of range of the whole rb_tree, pprev will point to the right-most node. rb_tree facility already provides a helper function, rb_last(), to do this task. We can leverage this instead of reimplementing it. This patch refines find_vma_prev() with rb_last() to make it a little nicer to read. [akpm@linux-foundation.org: little cleanup, per Vlastimil] Link: http://lkml.kernel.org/r/20190809001928.4950-1-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24 01:39:25 +03:00
struct rb_node *rb_node = rb_last(&mm->mm_rb);
*pprev = rb_node ? rb_entry(rb_node, struct vm_area_struct, vm_rb) : NULL;
mm: fix find_vma_prev Commit 6bd4837de96e ("mm: simplify find_vma_prev()") broke memory management on PA-RISC. After application of the patch, programs that allocate big arrays on the stack crash with segfault, for example, this will crash if compiled without optimization: int main() { char array[200000]; array[199999] = 0; return 0; } The reason is that PA-RISC has up-growing stack and the stack is usually the last memory area. In the above example, a page fault happens above the stack. Previously, if we passed too high address to find_vma_prev, it returned NULL and stored the last VMA in *pprev. After "simplify find_vma_prev" change, it stores NULL in *pprev. Consequently, the stack area is not found and it is not expanded, as it used to be before the change. This patch restores the old behavior and makes it return the last VMA in *pprev if the requested address is higher than address of any other VMA. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 04:52:03 +04:00
}
mm: simplify find_vma_prev() commit 297c5eee37 ("mm: make the vma list be doubly linked") added the vm_prev member to vm_area_struct. We can simplify find_vma_prev() by using it. Also, this change helps to improve page fault performance because it has stronger locality of reference. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-11 03:08:07 +04:00
return vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/*
* Verify that the stack growth is acceptable and
* update accounting. This is shared with both the
* grow-up and grow-down cases.
*/
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
static int acct_stack_growth(struct vm_area_struct *vma,
unsigned long size, unsigned long grow)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
struct mm_struct *mm = vma->vm_mm;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
unsigned long new_start;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* address space limit tests */
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
if (!may_expand_vm(mm, vma->vm_flags, grow))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -ENOMEM;
/* Stack limit test */
mm: use dedicated helper to access rlimit value Use rlimit() helper instead of manually writing whole chain from current task to rlim_cur. Link: http://lkml.kernel.org/r/20170705172811.8027-1-k.opasiak@samsung.com Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11 01:50:03 +03:00
if (size > rlimit(RLIMIT_STACK))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -ENOMEM;
/* mlock limit tests */
if (vma->vm_flags & VM_LOCKED) {
unsigned long locked;
unsigned long limit;
locked = mm->locked_vm + grow;
mm: use dedicated helper to access rlimit value Use rlimit() helper instead of manually writing whole chain from current task to rlim_cur. Link: http://lkml.kernel.org/r/20170705172811.8027-1-k.opasiak@samsung.com Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11 01:50:03 +03:00
limit = rlimit(RLIMIT_MEMLOCK);
mm: use rlimit helpers Make sure compiler won't do weird things with limits. E.g. fetching them twice may return 2 different values after writable limits are implemented. I.e. either use rlimit helpers added in 3e10e716abf3c71bdb5d86b8f507f9e72236c9cd ("resource: add helpers for fetching rlimits") or ACCESS_ONCE if not applicable. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:41:44 +03:00
limit >>= PAGE_SHIFT;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (locked > limit && !capable(CAP_IPC_LOCK))
return -ENOMEM;
}
[PATCH] Don't allow the stack to grow into hugetlb reserved regions When expanding the stack, we don't currently check if the VMA will cross into an area of the address space that is reserved for hugetlb pages. Subsequent faults on the expanded portion of such a VMA will confuse the low-level MMU code, resulting in an OOPS. Check for this. Signed-off-by: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-31 01:35:39 +03:00
/* Check to ensure the stack will not grow into a hugetlb-only region */
new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
vma->vm_end - size;
if (is_hugepage_only_range(vma->vm_mm, new_start, size))
return -EFAULT;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* Overcommit.. This must be the final test, as it will
* update security statistics.
*/
mm: pass correct mm when growing stack Tetsuo Handa reports seeing the WARN_ON(current->mm == NULL) in security_vm_enough_memory(), when do_execve() is touching the target mm's stack, to set up its args and environment. Yes, a UMH_NO_WAIT or UMH_WAIT_PROC call_usermodehelper() spawns an mm-less kernel thread to do the exec. And in any case, that vm_enough_memory check when growing stack ought to be done on the target mm, not on the execer's mm (though apart from the warning, it only makes a slight tweak to OVERCOMMIT_NEVER behaviour). Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-17 00:58:12 +04:00
if (security_vm_enough_memory_mm(mm, grow))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -ENOMEM;
return 0;
}
[PATCH] mm: ia64 use expand_upwards ia64 has expand_backing_store function for growing its Register Backing Store vma upwards. But more complete code for this purpose is found in the CONFIG_STACK_GROWSUP part of mm/mmap.c. Uglify its #ifdefs further to provide expand_upwards for ia64 as well as expand_stack for parisc. The Register Backing Store vma should be marked VM_ACCOUNT. Implement the intention of growing it only a page at a time, instead of passing an address outside of the vma to handle_mm_fault, with unknown consequences. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:16:20 +03:00
#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
[PATCH] mm: ia64 use expand_upwards ia64 has expand_backing_store function for growing its Register Backing Store vma upwards. But more complete code for this purpose is found in the CONFIG_STACK_GROWSUP part of mm/mmap.c. Uglify its #ifdefs further to provide expand_upwards for ia64 as well as expand_stack for parisc. The Register Backing Store vma should be marked VM_ACCOUNT. Implement the intention of growing it only a page at a time, instead of passing an address outside of the vma to handle_mm_fault, with unknown consequences. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:16:20 +03:00
* PA-RISC uses this for its stack; IA64 for its Register Backing Store.
* vma is the last one with address > vma->vm_end. Have to extend vma.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
[PATCH] mm: ia64 use expand_upwards ia64 has expand_backing_store function for growing its Register Backing Store vma upwards. But more complete code for this purpose is found in the CONFIG_STACK_GROWSUP part of mm/mmap.c. Uglify its #ifdefs further to provide expand_upwards for ia64 as well as expand_stack for parisc. The Register Backing Store vma should be marked VM_ACCOUNT. Implement the intention of growing it only a page at a time, instead of passing an address outside of the vma to handle_mm_fault, with unknown consequences. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:16:20 +03:00
int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
struct mm_struct *mm = vma->vm_mm;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
struct vm_area_struct *next;
unsigned long gap_addr;
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
int error = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (!(vma->vm_flags & VM_GROWSUP))
return -EFAULT;
Allow stack to grow up to address space limit Fix expand_upwards() on architectures with an upward-growing stack (parisc, metag and partly IA-64) to allow the stack to reliably grow exactly up to the address space limit given by TASK_SIZE. Signed-off-by: Helge Deller <deller@gmx.de> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 18:34:05 +03:00
/* Guard against exceeding limits of the address space. */
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
address &= PAGE_MASK;
mm: fix overflow check in expand_upwards() Jörn Engel noticed that the expand_upwards() function might not return -ENOMEM in case the requested address is (unsigned long)-PAGE_SIZE and if the architecture didn't defined TASK_SIZE as multiple of PAGE_SIZE. Affected architectures are arm, frv, m68k, blackfin, h8300 and xtensa which all define TASK_SIZE as 0xffffffff, but since none of those have an upwards-growing stack we currently have no actual issue. Nevertheless let's fix this just in case any of the architectures with an upward-growing stack (currently parisc, metag and partly ia64) define TASK_SIZE similar. Link: http://lkml.kernel.org/r/20170702192452.GA11868@p100.box Fixes: bd726c90b6b8 ("Allow stack to grow up to address space limit") Signed-off-by: Helge Deller <deller@gmx.de> Reported-by: Jörn Engel <joern@purestorage.com> Cc: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-15 00:49:38 +03:00
if (address >= (TASK_SIZE & PAGE_MASK))
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
return -ENOMEM;
Allow stack to grow up to address space limit Fix expand_upwards() on architectures with an upward-growing stack (parisc, metag and partly IA-64) to allow the stack to reliably grow exactly up to the address space limit given by TASK_SIZE. Signed-off-by: Helge Deller <deller@gmx.de> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 18:34:05 +03:00
address += PAGE_SIZE;
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
/* Enforce stack_guard_gap */
gap_addr = address + stack_guard_gap;
Allow stack to grow up to address space limit Fix expand_upwards() on architectures with an upward-growing stack (parisc, metag and partly IA-64) to allow the stack to reliably grow exactly up to the address space limit given by TASK_SIZE. Signed-off-by: Helge Deller <deller@gmx.de> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 18:34:05 +03:00
/* Guard against overflow */
if (gap_addr < address || gap_addr > TASK_SIZE)
gap_addr = TASK_SIZE;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
next = vma->vm_next;
mm/vma: make vma_is_accessible() available for general use Lets move vma_is_accessible() helper to include/linux/mm.h which makes it available for general use. While here, this replaces all remaining open encodings for VMA access check with vma_is_accessible(). Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Guo Ren <guoren@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paulburton@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Nick Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/1582520593-30704-3-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 06:03:47 +03:00
if (next && next->vm_start < gap_addr && vma_is_accessible(next)) {
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
if (!(next->vm_flags & VM_GROWSUP))
return -ENOMEM;
/* Check that both stack segments have the same anon_vma? */
}
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
/* We must make sure the anon_vma is allocated. */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
/*
* vma->vm_start/vm_end cannot change under us because the caller
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* is required to hold the mmap_lock in read mode. We need the
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
* anon_vma lock to serialize against concurrent expand_stacks.
*/
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
anon_vma_lock_write(vma->anon_vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Somebody else might have raced and expanded it already */
if (address > vma->vm_end) {
unsigned long size, grow;
size = address - vma->vm_start;
grow = (address - vma->vm_end) >> PAGE_SHIFT;
vm: fix vm_pgoff wrap in upward expansion Commit a626ca6a6564 ("vm: fix vm_pgoff wrap in stack expansion") fixed the case of an expanding mapping causing vm_pgoff wrapping when you had downward stack expansion. But there was another case where IA64 and PA-RISC expand mappings: upward expansion. This fixes that case too. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-10 04:44:42 +04:00
error = -ENOMEM;
if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
error = acct_stack_growth(vma, size, grow);
if (!error) {
mm: protect against concurrent vma expansion expand_stack() runs with a shared mmap_sem lock. Because of this, there could be multiple concurrent stack expansions in the same mm, which may cause problems in the vma gap update code. I propose to solve this by taking the mm->page_table_lock around such vma expansions, in order to avoid the concurrency issue. We only have to worry about concurrent expand_stack() calls here, since we hold a shared mmap_sem lock and all vma modificaitons other than expand_stack() are done under an exclusive mmap_sem lock. I previously tried to achieve the same effect by making sure all growable vmas in a given mm would share the same anon_vma, which we already lock here. However this turned out to be difficult - all of the schemes I tried for refcounting the growable anon_vma and clearing turned out ugly. So, I'm now proposing only the minimal fix. The overhead of taking the page table lock during stack expansion is expected to be small: glibc doesn't use expandable stacks for the threads it creates, so having multiple growable stacks is actually uncommon and we don't expect the page table lock to get bounced between threads. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:52:25 +04:00
/*
* vma_gap_update() doesn't support concurrent
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* updates, but we only hold a shared mmap_lock
mm: protect against concurrent vma expansion expand_stack() runs with a shared mmap_sem lock. Because of this, there could be multiple concurrent stack expansions in the same mm, which may cause problems in the vma gap update code. I propose to solve this by taking the mm->page_table_lock around such vma expansions, in order to avoid the concurrency issue. We only have to worry about concurrent expand_stack() calls here, since we hold a shared mmap_sem lock and all vma modificaitons other than expand_stack() are done under an exclusive mmap_sem lock. I previously tried to achieve the same effect by making sure all growable vmas in a given mm would share the same anon_vma, which we already lock here. However this turned out to be difficult - all of the schemes I tried for refcounting the growable anon_vma and clearing turned out ugly. So, I'm now proposing only the minimal fix. The overhead of taking the page table lock during stack expansion is expected to be small: glibc doesn't use expandable stacks for the threads it creates, so having multiple growable stacks is actually uncommon and we don't expect the page table lock to get bounced between threads. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:52:25 +04:00
* lock here, so we need to protect against
* concurrent vma expansions.
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
* anon_vma_lock_write() doesn't help here, as
mm: protect against concurrent vma expansion expand_stack() runs with a shared mmap_sem lock. Because of this, there could be multiple concurrent stack expansions in the same mm, which may cause problems in the vma gap update code. I propose to solve this by taking the mm->page_table_lock around such vma expansions, in order to avoid the concurrency issue. We only have to worry about concurrent expand_stack() calls here, since we hold a shared mmap_sem lock and all vma modificaitons other than expand_stack() are done under an exclusive mmap_sem lock. I previously tried to achieve the same effect by making sure all growable vmas in a given mm would share the same anon_vma, which we already lock here. However this turned out to be difficult - all of the schemes I tried for refcounting the growable anon_vma and clearing turned out ugly. So, I'm now proposing only the minimal fix. The overhead of taking the page table lock during stack expansion is expected to be small: glibc doesn't use expandable stacks for the threads it creates, so having multiple growable stacks is actually uncommon and we don't expect the page table lock to get bounced between threads. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:52:25 +04:00
* we don't guarantee that all growable vmas
* in a mm share the same root anon vma.
* So, we reuse mm->page_table_lock to guard
* against concurrent vma expansions.
*/
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
spin_lock(&mm->page_table_lock);
mm: fix the racy mm->locked_vm change in "mm->locked_vm += grow" and vm_stat_account() in acct_stack_growth() are not safe; multiple threads using the same ->mm can do this at the same time trying to expans different vma's under down_read(mmap_sem). This means that one of the "locked_vm += grow" changes can be lost and we can miss munlock_vma_pages_all() later. Move this code into the caller(s) under mm->page_table_lock. All other updates to ->locked_vm hold mmap_sem for writing. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:14 +03:00
if (vma->vm_flags & VM_LOCKED)
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
mm->locked_vm += grow;
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
vm_stat_account(mm, vma->vm_flags, grow);
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
anon_vma_interval_tree_pre_update_vma(vma);
vm: fix vm_pgoff wrap in upward expansion Commit a626ca6a6564 ("vm: fix vm_pgoff wrap in stack expansion") fixed the case of an expanding mapping causing vm_pgoff wrapping when you had downward stack expansion. But there was another case where IA64 and PA-RISC expand mappings: upward expansion. This fixes that case too. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-10 04:44:42 +04:00
vma->vm_end = address;
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
anon_vma_interval_tree_post_update_vma(vma);
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
if (vma->vm_next)
vma_gap_update(vma->vm_next);
else
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
mm->highest_vm_end = vm_end_gap(vma);
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
spin_unlock(&mm->page_table_lock);
mm: protect against concurrent vma expansion expand_stack() runs with a shared mmap_sem lock. Because of this, there could be multiple concurrent stack expansions in the same mm, which may cause problems in the vma gap update code. I propose to solve this by taking the mm->page_table_lock around such vma expansions, in order to avoid the concurrency issue. We only have to worry about concurrent expand_stack() calls here, since we hold a shared mmap_sem lock and all vma modificaitons other than expand_stack() are done under an exclusive mmap_sem lock. I previously tried to achieve the same effect by making sure all growable vmas in a given mm would share the same anon_vma, which we already lock here. However this turned out to be difficult - all of the schemes I tried for refcounting the growable anon_vma and clearing turned out ugly. So, I'm now proposing only the minimal fix. The overhead of taking the page table lock during stack expansion is expected to be small: glibc doesn't use expandable stacks for the threads it creates, so having multiple growable stacks is actually uncommon and we don't expect the page table lock to get bounced between threads. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:52:25 +04:00
vm: fix vm_pgoff wrap in upward expansion Commit a626ca6a6564 ("vm: fix vm_pgoff wrap in stack expansion") fixed the case of an expanding mapping causing vm_pgoff wrapping when you had downward stack expansion. But there was another case where IA64 and PA-RISC expand mappings: upward expansion. This fixes that case too. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-10 04:44:42 +04:00
perf_event_mmap(vma);
}
perf: Add non-exec mmap() tracking Add the capacility to track data mmap()s. This can be used together with PERF_SAMPLE_ADDR for data profiling. Signed-off-by: Anton Blanchard <anton@samba.org> [Updated code for stable perf ABI] Signed-off-by: Eric B Munson <ebmunson@us.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1274193049-25997-1-git-send-email-ebmunson@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-18 18:30:49 +04:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
anon_vma_unlock_write(vma->anon_vma);
mm, thp: fix collapsing of hugepages on madvise If an anonymous mapping is not allowed to fault thp memory and then madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never collapse this memory into thp memory. This occurs because the madvise(2) handler for thp, hugepage_madvise(), clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags until the final action of madvise_behavior(). This causes the khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when the vma had previously had VM_NOHUGEPAGE set. Fix this by passing the correct vma flags to the khugepaged mm slot handler. There's no chance khugepaged can run on this vma until after madvise_behavior() returns since we hold mm->mmap_sem. It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags in hugepage_advise(), but I didn't want to introduce special case behavior into madvise_behavior(). I think it's best to just let it always set vma->vm_flags itself. Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Suleiman Souhlal <suleiman@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-30 00:50:31 +03:00
khugepaged_enter_vma_merge(vma, vma->vm_flags);
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
validate_mm(mm);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return error;
}
[PATCH] mm: ia64 use expand_upwards ia64 has expand_backing_store function for growing its Register Backing Store vma upwards. But more complete code for this purpose is found in the CONFIG_STACK_GROWSUP part of mm/mmap.c. Uglify its #ifdefs further to provide expand_upwards for ia64 as well as expand_stack for parisc. The Register Backing Store vma should be marked VM_ACCOUNT. Implement the intention of growing it only a page at a time, instead of passing an address outside of the vma to handle_mm_fault, with unknown consequences. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:16:20 +03:00
#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* vma is the first one with address < vma->vm_start. Have to extend vma.
*/
mm: make expand_downwards() symmetrical with expand_upwards() Currently we have expand_upwards exported while expand_downwards is accessible only via expand_stack or expand_stack_downwards. check_stack_guard_page is a nice example of the asymmetry. It uses expand_stack for VM_GROWSDOWN while expand_upwards is called for VM_GROWSUP case. Let's clean this up by exporting both functions and make those names consistent. Let's use expand_{upwards,downwards} because expanding doesn't always involve stack manipulation (an example is ia64_do_page_fault which uses expand_upwards for registers backing store expansion). expand_downwards has to be defined for both CONFIG_STACK_GROWS{UP,DOWN} because get_arg_page calls the downwards version in the early process initialization phase for growsup configuration. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Hugh Dickins <hughd@google.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:44 +04:00
int expand_downwards(struct vm_area_struct *vma,
mm: variable length argument support Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly from the old mm into the new mm. We create the new mm before the binfmt code runs, and place the new stack at the very top of the address space. Once the binfmt code runs and figures out where the stack should be, we move it downwards. It is a bit peculiar in that we have one task with two mm's, one of which is inactive. [a.p.zijlstra@chello.nl: limit stack size] Signed-off-by: Ollie Wild <aaw@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <linux-arch@vger.kernel.org> Cc: Hugh Dickins <hugh@veritas.com> [bunk@stusta.de: unexport bprm_mm_init] Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 12:48:16 +04:00
unsigned long address)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
struct mm_struct *mm = vma->vm_mm;
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
struct vm_area_struct *prev;
mm: enforce min addr even if capable() in expand_downwards() security_mmap_addr() does a capability check with current_cred(), but we can reach this code from contexts like a VFS write handler where current_cred() must not be used. This can be abused on systems without SMAP to make NULL pointer dereferences exploitable again. Fixes: 8869477a49c3 ("security: protect from stack expansion into low vm addresses") Cc: stable@kernel.org Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-02-27 23:29:52 +03:00
int error = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
security: protect from stack expantion into low vm addresses Add security checks to make sure we are not attempting to expand the stack into memory protected by mmap_min_addr Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2007-11-27 02:47:26 +03:00
address &= PAGE_MASK;
mm: enforce min addr even if capable() in expand_downwards() security_mmap_addr() does a capability check with current_cred(), but we can reach this code from contexts like a VFS write handler where current_cred() must not be used. This can be abused on systems without SMAP to make NULL pointer dereferences exploitable again. Fixes: 8869477a49c3 ("security: protect from stack expansion into low vm addresses") Cc: stable@kernel.org Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-02-27 23:29:52 +03:00
if (address < mmap_min_addr)
return -EPERM;
security: protect from stack expantion into low vm addresses Add security checks to make sure we are not attempting to expand the stack into memory protected by mmap_min_addr Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2007-11-27 02:47:26 +03:00
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
/* Enforce stack_guard_gap */
prev = vma->vm_prev;
mm/mmap.c: expand_downwards: don't require the gap if !vm_prev expand_stack(vma) fails if address < stack_guard_gap even if there is no vma->vm_prev. I don't think this makes sense, and we didn't do this before the recent commit 1be7107fbe18 ("mm: larger stack guard gap, between vmas"). We do not need a gap in this case, any address is fine as long as security_mmap_addr() doesn't object. This also simplifies the code, we know that address >= prev->vm_end and thus underflow is not possible. Link: http://lkml.kernel.org/r/20170628175258.GA24881@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Larry Woodman <lwoodman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11 01:49:54 +03:00
/* Check that both stack segments have the same anon_vma? */
if (prev && !(prev->vm_flags & VM_GROWSDOWN) &&
mm/vma: make vma_is_accessible() available for general use Lets move vma_is_accessible() helper to include/linux/mm.h which makes it available for general use. While here, this replaces all remaining open encodings for VMA access check with vma_is_accessible(). Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Guo Ren <guoren@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paulburton@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Nick Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/1582520593-30704-3-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 06:03:47 +03:00
vma_is_accessible(prev)) {
mm/mmap.c: expand_downwards: don't require the gap if !vm_prev expand_stack(vma) fails if address < stack_guard_gap even if there is no vma->vm_prev. I don't think this makes sense, and we didn't do this before the recent commit 1be7107fbe18 ("mm: larger stack guard gap, between vmas"). We do not need a gap in this case, any address is fine as long as security_mmap_addr() doesn't object. This also simplifies the code, we know that address >= prev->vm_end and thus underflow is not possible. Link: http://lkml.kernel.org/r/20170628175258.GA24881@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Larry Woodman <lwoodman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11 01:49:54 +03:00
if (address - prev->vm_end < stack_guard_gap)
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
return -ENOMEM;
}
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
/* We must make sure the anon_vma is allocated. */
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* vma->vm_start/vm_end cannot change under us because the caller
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* is required to hold the mmap_lock in read mode. We need the
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
* anon_vma lock to serialize against concurrent expand_stacks.
*/
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
anon_vma_lock_write(vma->anon_vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Somebody else might have raced and expanded it already */
if (address < vma->vm_start) {
unsigned long size, grow;
size = vma->vm_end - address;
grow = (vma->vm_start - address) >> PAGE_SHIFT;
vm: fix vm_pgoff wrap in stack expansion Commit 982134ba6261 ("mm: avoid wrapping vm_pgoff in mremap()") fixed the case of a expanding mapping causing vm_pgoff wrapping when you used mremap. But there was another case where we expand mappings hiding in plain sight: the automatic stack expansion. This fixes that case too. This one also found by Robert Święcki, using his nasty system call fuzzer tool. Good job. Reported-and-tested-by: Robert Święcki <robert@swiecki.net> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-13 19:07:28 +04:00
error = -ENOMEM;
if (grow <= vma->vm_pgoff) {
error = acct_stack_growth(vma, size, grow);
if (!error) {
mm: protect against concurrent vma expansion expand_stack() runs with a shared mmap_sem lock. Because of this, there could be multiple concurrent stack expansions in the same mm, which may cause problems in the vma gap update code. I propose to solve this by taking the mm->page_table_lock around such vma expansions, in order to avoid the concurrency issue. We only have to worry about concurrent expand_stack() calls here, since we hold a shared mmap_sem lock and all vma modificaitons other than expand_stack() are done under an exclusive mmap_sem lock. I previously tried to achieve the same effect by making sure all growable vmas in a given mm would share the same anon_vma, which we already lock here. However this turned out to be difficult - all of the schemes I tried for refcounting the growable anon_vma and clearing turned out ugly. So, I'm now proposing only the minimal fix. The overhead of taking the page table lock during stack expansion is expected to be small: glibc doesn't use expandable stacks for the threads it creates, so having multiple growable stacks is actually uncommon and we don't expect the page table lock to get bounced between threads. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:52:25 +04:00
/*
* vma_gap_update() doesn't support concurrent
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* updates, but we only hold a shared mmap_lock
mm: protect against concurrent vma expansion expand_stack() runs with a shared mmap_sem lock. Because of this, there could be multiple concurrent stack expansions in the same mm, which may cause problems in the vma gap update code. I propose to solve this by taking the mm->page_table_lock around such vma expansions, in order to avoid the concurrency issue. We only have to worry about concurrent expand_stack() calls here, since we hold a shared mmap_sem lock and all vma modificaitons other than expand_stack() are done under an exclusive mmap_sem lock. I previously tried to achieve the same effect by making sure all growable vmas in a given mm would share the same anon_vma, which we already lock here. However this turned out to be difficult - all of the schemes I tried for refcounting the growable anon_vma and clearing turned out ugly. So, I'm now proposing only the minimal fix. The overhead of taking the page table lock during stack expansion is expected to be small: glibc doesn't use expandable stacks for the threads it creates, so having multiple growable stacks is actually uncommon and we don't expect the page table lock to get bounced between threads. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:52:25 +04:00
* lock here, so we need to protect against
* concurrent vma expansions.
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
* anon_vma_lock_write() doesn't help here, as
mm: protect against concurrent vma expansion expand_stack() runs with a shared mmap_sem lock. Because of this, there could be multiple concurrent stack expansions in the same mm, which may cause problems in the vma gap update code. I propose to solve this by taking the mm->page_table_lock around such vma expansions, in order to avoid the concurrency issue. We only have to worry about concurrent expand_stack() calls here, since we hold a shared mmap_sem lock and all vma modificaitons other than expand_stack() are done under an exclusive mmap_sem lock. I previously tried to achieve the same effect by making sure all growable vmas in a given mm would share the same anon_vma, which we already lock here. However this turned out to be difficult - all of the schemes I tried for refcounting the growable anon_vma and clearing turned out ugly. So, I'm now proposing only the minimal fix. The overhead of taking the page table lock during stack expansion is expected to be small: glibc doesn't use expandable stacks for the threads it creates, so having multiple growable stacks is actually uncommon and we don't expect the page table lock to get bounced between threads. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:52:25 +04:00
* we don't guarantee that all growable vmas
* in a mm share the same root anon vma.
* So, we reuse mm->page_table_lock to guard
* against concurrent vma expansions.
*/
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
spin_lock(&mm->page_table_lock);
mm: fix the racy mm->locked_vm change in "mm->locked_vm += grow" and vm_stat_account() in acct_stack_growth() are not safe; multiple threads using the same ->mm can do this at the same time trying to expans different vma's under down_read(mmap_sem). This means that one of the "locked_vm += grow" changes can be lost and we can miss munlock_vma_pages_all() later. Move this code into the caller(s) under mm->page_table_lock. All other updates to ->locked_vm hold mmap_sem for writing. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:14 +03:00
if (vma->vm_flags & VM_LOCKED)
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
mm->locked_vm += grow;
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
vm_stat_account(mm, vma->vm_flags, grow);
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
anon_vma_interval_tree_pre_update_vma(vma);
vm: fix vm_pgoff wrap in stack expansion Commit 982134ba6261 ("mm: avoid wrapping vm_pgoff in mremap()") fixed the case of a expanding mapping causing vm_pgoff wrapping when you used mremap. But there was another case where we expand mappings hiding in plain sight: the automatic stack expansion. This fixes that case too. This one also found by Robert Święcki, using his nasty system call fuzzer tool. Good job. Reported-and-tested-by: Robert Święcki <robert@swiecki.net> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-13 19:07:28 +04:00
vma->vm_start = address;
vma->vm_pgoff -= grow;
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
anon_vma_interval_tree_post_update_vma(vma);
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
vma_gap_update(vma);
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
spin_unlock(&mm->page_table_lock);
mm: protect against concurrent vma expansion expand_stack() runs with a shared mmap_sem lock. Because of this, there could be multiple concurrent stack expansions in the same mm, which may cause problems in the vma gap update code. I propose to solve this by taking the mm->page_table_lock around such vma expansions, in order to avoid the concurrency issue. We only have to worry about concurrent expand_stack() calls here, since we hold a shared mmap_sem lock and all vma modificaitons other than expand_stack() are done under an exclusive mmap_sem lock. I previously tried to achieve the same effect by making sure all growable vmas in a given mm would share the same anon_vma, which we already lock here. However this turned out to be difficult - all of the schemes I tried for refcounting the growable anon_vma and clearing turned out ugly. So, I'm now proposing only the minimal fix. The overhead of taking the page table lock during stack expansion is expected to be small: glibc doesn't use expandable stacks for the threads it creates, so having multiple growable stacks is actually uncommon and we don't expect the page table lock to get bounced between threads. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-13 01:52:25 +04:00
vm: fix vm_pgoff wrap in stack expansion Commit 982134ba6261 ("mm: avoid wrapping vm_pgoff in mremap()") fixed the case of a expanding mapping causing vm_pgoff wrapping when you used mremap. But there was another case where we expand mappings hiding in plain sight: the automatic stack expansion. This fixes that case too. This one also found by Robert Święcki, using his nasty system call fuzzer tool. Good job. Reported-and-tested-by: Robert Święcki <robert@swiecki.net> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-13 19:07:28 +04:00
perf_event_mmap(vma);
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
}
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if anon_vma appeared between lock and unlock. We have to check anon_vma first or call anon_vma_prepare() to be sure that it's here. There are only few users of these legacy helpers. Let's get rid of them. This patch fixes anon_vma lock imbalance in validate_mm(). Write lock isn't required here, read lock is enough. And reorders expand_downwards/expand_upwards: security_mmap_addr() and wrapping-around check don't have to be under anon vma lock. Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-06 02:36:50 +03:00
anon_vma_unlock_write(vma->anon_vma);
mm, thp: fix collapsing of hugepages on madvise If an anonymous mapping is not allowed to fault thp memory and then madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never collapse this memory into thp memory. This occurs because the madvise(2) handler for thp, hugepage_madvise(), clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags until the final action of madvise_behavior(). This causes the khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when the vma had previously had VM_NOHUGEPAGE set. Fix this by passing the correct vma flags to the khugepaged mm slot handler. There's no chance khugepaged can run on this vma until after madvise_behavior() returns since we hold mm->mmap_sem. It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags in hugepage_advise(), but I didn't want to introduce special case behavior into madvise_behavior(). I think it's best to just let it always set vma->vm_flags itself. Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Suleiman Souhlal <suleiman@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-30 00:50:31 +03:00
khugepaged_enter_vma_merge(vma, vma->vm_flags);
mm: add the "struct mm_struct *mm" local into Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm, a local variable makes sense imho. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:17 +03:00
validate_mm(mm);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return error;
}
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
/* enforced gap between the expanding stack and other mappings. */
unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
static int __init cmdline_parse_stack_guard_gap(char *p)
{
unsigned long val;
char *endptr;
val = simple_strtoul(p, &endptr, 10);
if (!*endptr)
stack_guard_gap = val << PAGE_SHIFT;
return 0;
}
__setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
mm: variable length argument support Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly from the old mm into the new mm. We create the new mm before the binfmt code runs, and place the new stack at the very top of the address space. Once the binfmt code runs and figures out where the stack should be, we move it downwards. It is a bit peculiar in that we have one task with two mm's, one of which is inactive. [a.p.zijlstra@chello.nl: limit stack size] Signed-off-by: Ollie Wild <aaw@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <linux-arch@vger.kernel.org> Cc: Hugh Dickins <hugh@veritas.com> [bunk@stusta.de: unexport bprm_mm_init] Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 12:48:16 +04:00
#ifdef CONFIG_STACK_GROWSUP
int expand_stack(struct vm_area_struct *vma, unsigned long address)
{
return expand_upwards(vma, address);
}
struct vm_area_struct *
find_extend_vma(struct mm_struct *mm, unsigned long addr)
{
struct vm_area_struct *vma, *prev;
addr &= PAGE_MASK;
vma = find_vma_prev(mm, addr, &prev);
if (vma && (vma->vm_start <= addr))
return vma;
coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping The core dumping code has always run without holding the mmap_sem for writing, despite that is the only way to ensure that the entire vma layout will not change from under it. Only using some signal serialization on the processes belonging to the mm is not nearly enough. This was pointed out earlier. For example in Hugh's post from Jul 2017: https://lkml.kernel.org/r/alpine.LSU.2.11.1707191716030.2055@eggly.anvils "Not strictly relevant here, but a related note: I was very surprised to discover, only quite recently, how handle_mm_fault() may be called without down_read(mmap_sem) - when core dumping. That seems a misguided optimization to me, which would also be nice to correct" In particular because the growsdown and growsup can move the vm_start/vm_end the various loops the core dump does around the vma will not be consistent if page faults can happen concurrently. Pretty much all users calling mmget_not_zero()/get_task_mm() and then taking the mmap_sem had the potential to introduce unexpected side effects in the core dumping code. Adding mmap_sem for writing around the ->core_dump invocation is a viable long term fix, but it requires removing all copy user and page faults and to replace them with get_dump_page() for all binary formats which is not suitable as a short term fix. For the time being this solution manually covers the places that can confuse the core dump either by altering the vma layout or the vma flags while it runs. Once ->core_dump runs under mmap_sem for writing the function mmget_still_valid() can be dropped. Allowing mmap_sem protected sections to run in parallel with the coredump provides some minor parallelism advantage to the swapoff code (which seems to be safe enough by never mangling any vma field and can keep doing swapins in parallel to the core dumping) and to some other corner case. In order to facilitate the backporting I added "Fixes: 86039bd3b4e6" however the side effect of this same race condition in /proc/pid/mem should be reproducible since before 2.6.12-rc2 so I couldn't add any other "Fixes:" because there's no hash beyond the git genesis commit. Because find_extend_vma() is the only location outside of the process context that could modify the "mm" structures under mmap_sem for reading, by adding the mmget_still_valid() check to it, all other cases that take the mmap_sem for reading don't need the new check after mmget_not_zero()/get_task_mm(). The expand_stack() in page fault context also doesn't need the new check, because all tasks under core dumping are frozen. Link: http://lkml.kernel.org/r/20190325224949.11068-1-aarcange@redhat.com Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Jann Horn <jannh@google.com> Suggested-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jann Horn <jannh@google.com> Acked-by: Jason Gunthorpe <jgg@mellanox.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-19 03:50:52 +03:00
/* don't alter vm_end if the coredump is running */
mm: remove the now-unnecessary mmget_still_valid() hack The preceding patches have ensured that core dumping properly takes the mmap_lock. Thanks to that, we can now remove mmget_still_valid() and all its users. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Link: http://lkml.kernel.org/r/20200827114932.3572699-8-jannh@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 06:13:00 +03:00
if (!prev || expand_stack(prev, addr))
mm: variable length argument support Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly from the old mm into the new mm. We create the new mm before the binfmt code runs, and place the new stack at the very top of the address space. Once the binfmt code runs and figures out where the stack should be, we move it downwards. It is a bit peculiar in that we have one task with two mm's, one of which is inactive. [a.p.zijlstra@chello.nl: limit stack size] Signed-off-by: Ollie Wild <aaw@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <linux-arch@vger.kernel.org> Cc: Hugh Dickins <hugh@veritas.com> [bunk@stusta.de: unexport bprm_mm_init] Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 12:48:16 +04:00
return NULL;
mm: directly use __mlock_vma_pages_range() in find_extend_vma() In find_extend_vma(), we don't need mlock_vma_pages_range() to verify the vma type - we know we're working with a stack. So, we can call directly into __mlock_vma_pages_range(), and remove the last make_pages_present() call site. Note that we don't use mm_populate() here, so we can't release the mmap_sem while allocating new stack pages. This is deemed acceptable, because the stack vmas grow by a bounded number of pages at a time, and these are anon pages so we don't have to read from disk to populate them. Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:44 +04:00
if (prev->vm_flags & VM_LOCKED)
mm: rename __mlock_vma_pages_range() to populate_vma_page_range() __mlock_vma_pages_range() doesn't necessarily mlock pages. It depends on vma flags. The same codepath is used for MAP_POPULATE. Let's rename __mlock_vma_pages_range() to populate_vma_page_range(). This patch also drops mlock_vma_pages_range() references from documentation. It has gone in cea10a19b797 ("mm: directly use __mlock_vma_pages_range() in find_extend_vma()"). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 01:44:39 +03:00
populate_vma_page_range(prev, addr, prev->vm_end, NULL);
mm: variable length argument support Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly from the old mm into the new mm. We create the new mm before the binfmt code runs, and place the new stack at the very top of the address space. Once the binfmt code runs and figures out where the stack should be, we move it downwards. It is a bit peculiar in that we have one task with two mm's, one of which is inactive. [a.p.zijlstra@chello.nl: limit stack size] Signed-off-by: Ollie Wild <aaw@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <linux-arch@vger.kernel.org> Cc: Hugh Dickins <hugh@veritas.com> [bunk@stusta.de: unexport bprm_mm_init] Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 12:48:16 +04:00
return prev;
}
#else
int expand_stack(struct vm_area_struct *vma, unsigned long address)
{
return expand_downwards(vma, address);
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
struct vm_area_struct *
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
find_extend_vma(struct mm_struct *mm, unsigned long addr)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
struct vm_area_struct *vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
unsigned long start;
addr &= PAGE_MASK;
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
vma = find_vma(mm, addr);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (!vma)
return NULL;
if (vma->vm_start <= addr)
return vma;
if (!(vma->vm_flags & VM_GROWSDOWN))
return NULL;
start = vma->vm_start;
if (expand_stack(vma, addr))
return NULL;
mm: directly use __mlock_vma_pages_range() in find_extend_vma() In find_extend_vma(), we don't need mlock_vma_pages_range() to verify the vma type - we know we're working with a stack. So, we can call directly into __mlock_vma_pages_range(), and remove the last make_pages_present() call site. Note that we don't use mm_populate() here, so we can't release the mmap_sem while allocating new stack pages. This is deemed acceptable, because the stack vmas grow by a bounded number of pages at a time, and these are anon pages so we don't have to read from disk to populate them. Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:44 +04:00
if (vma->vm_flags & VM_LOCKED)
mm: rename __mlock_vma_pages_range() to populate_vma_page_range() __mlock_vma_pages_range() doesn't necessarily mlock pages. It depends on vma flags. The same codepath is used for MAP_POPULATE. Let's rename __mlock_vma_pages_range() to populate_vma_page_range(). This patch also drops mlock_vma_pages_range() references from documentation. It has gone in cea10a19b797 ("mm: directly use __mlock_vma_pages_range() in find_extend_vma()"). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 01:44:39 +03:00
populate_vma_page_range(vma, addr, start, NULL);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return vma;
}
#endif
mm: export find_extend_vma() and handle_mm_fault() for driver use This lets drivers like the AMD IOMMUv2 driver handle faults a bit more simply, rather than doing tricks with page refs and get_user_pages(). Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Oded Gabbay <oded.gabbay@amd.com> Cc: Joerg Roedel <jroedel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:55:27 +03:00
EXPORT_SYMBOL_GPL(find_extend_vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
[PATCH] mm: remove_vma_list consolidation unmap_vma doesn't amount to much, let's put it inside unmap_vma_list. Except it doesn't unmap anything, unmap_region just did the unmapping: rename it to remove_vma_list. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:56 +03:00
* Ok - we have the memory areas we should free on the vma list,
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
* so release them, and do the vma updates.
[PATCH] mm: remove_vma_list consolidation unmap_vma doesn't amount to much, let's put it inside unmap_vma_list. Except it doesn't unmap anything, unmap_region just did the unmapping: rename it to remove_vma_list. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:56 +03:00
*
* Called with the mm semaphore held.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
[PATCH] mm: remove_vma_list consolidation unmap_vma doesn't amount to much, let's put it inside unmap_vma_list. Except it doesn't unmap anything, unmap_region just did the unmapping: rename it to remove_vma_list. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:56 +03:00
static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces The VM accounting makes no sense at this level, and half of the callers didn't ever actually use the end result. The only time we want to unaccount the memory is when we actually remove the vma, so do the accounting at that point instead. This simplifies the interfaces (no need to pass down that silly page counter to functions that really don't care), and also makes it much more obvious what is actually going on: we do vm_[un]acct_memory() when adding or removing the vma, not on random page walking. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-07 00:54:06 +04:00
unsigned long nr_accounted = 0;
[PATCH] mm: update_hiwaters just in time update_mem_hiwater has attracted various criticisms, in particular from those concerned with mm scalability. Originally it was called whenever rss or total_vm got raised. Then many of those callsites were replaced by a timer tick call from account_system_time. Now Frank van Maarseveen reports that to be found inadequate. How about this? Works for Frank. Replace update_mem_hiwater, a poor combination of two unrelated ops, by macros update_hiwater_rss and update_hiwater_vm. Don't attempt to keep mm->hiwater_rss up to date at timer tick, nor every time we raise rss (usually by 1): those are hot paths. Do the opposite, update only when about to lower rss (usually by many), or just before final accounting in do_exit. Handle mm->hiwater_vm in the same way, though it's much less of an issue. Demand that whoever collects these hiwater statistics do the work of taking the maximum with rss or total_vm. And there has been no collector of these hiwater statistics in the tree. The new convention needs an example, so match Frank's usage by adding a VmPeak line above VmSize to /proc/<pid>/status, and also a VmHWM line above VmRSS (High-Water-Mark or High-Water-Memory). There was a particular anomaly during mremap move, that hiwater_vm might be captured too high. A fleeting such anomaly remains, but it's quickly corrected now, whereas before it would stick. What locking? None: if the app is racy then these statistics will be racy, it's not worth any overhead to make them exact. But whenever it suits, hiwater_vm is updated under exclusive mmap_sem, and hiwater_rss under page_table_lock (for now) or with preemption disabled (later on): without going to any trouble, minimize the time between reading current values and updating, to minimize those occasions when a racing thread bumps a count up and back down in between. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:16:18 +03:00
/* Update high watermark before we lower total_vm */
update_hiwater_vm(mm);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
do {
[PATCH] mm: remove_vma_list consolidation unmap_vma doesn't amount to much, let's put it inside unmap_vma_list. Except it doesn't unmap anything, unmap_region just did the unmapping: rename it to remove_vma_list. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:56 +03:00
long nrpages = vma_pages(vma);
vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces The VM accounting makes no sense at this level, and half of the callers didn't ever actually use the end result. The only time we want to unaccount the memory is when we actually remove the vma, so do the accounting at that point instead. This simplifies the interfaces (no need to pass down that silly page counter to functions that really don't care), and also makes it much more obvious what is actually going on: we do vm_[un]acct_memory() when adding or removing the vma, not on random page walking. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-07 00:54:06 +04:00
if (vma->vm_flags & VM_ACCOUNT)
nr_accounted += nrpages;
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
vm_stat_account(mm, vma->vm_flags, -nrpages);
[PATCH] mm: unlink_file_vma, remove_vma Divide remove_vm_struct into two parts: first anon_vma_unlink plus unlink_file_vma, to unlink the vma from the list and tree by which rmap or vmtruncate might find it; then remove_vma to close, fput and free. The intention here is to do the anon_vma_unlink and unlink_file_vma earlier, in free_pgtables before freeing any page tables: so we can be sure that any page tables traversed by rmap and vmtruncate are stable (and other, ordinary cases are stabilized by holding mmap_sem). This will be crucial to traversing pgd,pud,pmd without page_table_lock. But testing the split-out patch showed that lifting the page_table_lock is symbiotically necessary to make this change - the lock ordering is wrong to move those unlinks into free_pgtables while it's under ptlock. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:57 +03:00
vma = remove_vma(vma);
[PATCH] freepgt: mpnt to vma cleanup While dabbling here in mmap.c, clean up mysterious "mpnt"s to "vma"s. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:18 +04:00
} while (vma);
vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces The VM accounting makes no sense at this level, and half of the callers didn't ever actually use the end result. The only time we want to unaccount the memory is when we actually remove the vma, so do the accounting at that point instead. This simplifies the interfaces (no need to pass down that silly page counter to functions that really don't care), and also makes it much more obvious what is actually going on: we do vm_[un]acct_memory() when adding or removing the vma, not on random page walking. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-07 00:54:06 +04:00
vm_unacct_memory(nr_accounted);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
validate_mm(mm);
}
/*
* Get rid of page table information in the indicated region.
*
[PATCH] fix locking comment in unmap_region() That comment is plain wrong (we even take the pagetable lock inside unmap_region()). Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-21 20:55:37 +04:00
* Called with the mm semaphore held.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
static void unmap_region(struct mm_struct *mm,
[PATCH] freepgt: free_pgtables use vma list Recent woes with some arches needing their own pgd_addr_end macro; and 4-level clear_page_range regression since 2.6.10's clear_page_tables; and its long-standing well-known inefficiency in searching throughout the higher-level page tables for those few entries to clear and free: all can be blamed on ignoring the list of vmas when we free page tables. Replace exit_mmap's clear_page_range of the total user address space by free_pgtables operating on the mm's vma list; unmap_region use it in the same way, giving floor and ceiling beyond which it may not free tables. This brings lmbench fork/exec/sh numbers back to 2.6.10 (unless preempt is enabled, in which case latency fixes spoil unmap_vmas throughput). Beware: the do_mmap_pgoff driver failure case must now use unmap_region instead of zap_page_range, since a page table might have been allocated, and can only be freed while it is touched by some vma. Move free_pgtables from mmap.c to memory.c, where its lower levels are adapted from the clear_page_range levels. (Most of free_pgtables' old code was actually for a non-existent case, prev not properly set up, dating from before hch gave us split_vma.) Pass mmu_gather** in the public interfaces, since we might want to add latency lockdrops later; but no attempt to do so yet, going by vma should itself reduce latency. But what if is_hugepage_only_range? Those ia64 and ppc64 cases need careful examination: put that off until a later patch of the series. What of x86_64's 32bit vdso page __map_syscall32 maps outside any vma? And the range to sparc64's flush_tlb_pgtables? It's less clear to me now that we need to do more than is done here - every PMD_SIZE ever occupied will be flushed, do we really have to flush every PGDIR_SIZE ever partially occupied? A shame to complicate it unnecessarily. Special thanks to David Miller for time spent repairing my ceilings. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:15 +04:00
struct vm_area_struct *vma, struct vm_area_struct *prev,
unsigned long start, unsigned long end)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm/mmap: add inline vma_next() for readability of mmap code There are three places that the next vma is required which uses the same block of code. Replace the block with a function and add comments on what happens in the case where NULL is encountered. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200818154707.2515169-1-Liam.Howlett@Oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 02:14:06 +03:00
struct vm_area_struct *next = vma_next(mm, prev);
mm: mmu_gather rework Rework the existing mmu_gather infrastructure. The direct purpose of these patches was to allow preemptible mmu_gather, but even without that I think these patches provide an improvement to the status quo. The first 9 patches rework the mmu_gather infrastructure. For review purpose I've split them into generic and per-arch patches with the last of those a generic cleanup. The next patch provides generic RCU page-table freeing, and the followup is a patch converting s390 to use this. I've also got 4 patches from DaveM lined up (not included in this series) that uses this to implement gup_fast() for sparc64. Then there is one patch that extends the generic mmu_gather batching. After that follow the mm preemptibility patches, these make part of the mm a lot more preemptible. It converts i_mmap_lock and anon_vma->lock to mutexes which together with the mmu_gather rework makes mmu_gather preemptible as well. Making i_mmap_lock a mutex also enables a clean-up of the truncate code. This also allows for preemptible mmu_notifiers, something that XPMEM I think wants. Furthermore, it removes the new and universially detested unmap_mutex. This patch: Remove the first obstacle towards a fully preemptible mmu_gather. The current scheme assumes mmu_gather is always done with preemption disabled and uses per-cpu storage for the page batches. Change this to try and allocate a page for batching and in case of failure, use a small on-stack array to make some progress. Preemptible mmu_gather is desired in general and usable once i_mmap_lock becomes a mutex. Doing it before the mutex conversion saves us from having to rework the code by moving the mmu_gather bits inside the pte_lock. Also avoid flushing the tlb batches from under the pte lock, this is useful even without the i_mmap_lock conversion as it significantly reduces pte lock hold times. [akpm@linux-foundation.org: fix comment tpyo] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Tony Luck <tony.luck@intel.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:45 +04:00
struct mmu_gather tlb;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
lru_add_drain();
Fix TLB gather virtual address range invalidation corner cases Ben Tebulin reported: "Since v3.7.2 on two independent machines a very specific Git repository fails in 9/10 cases on git-fsck due to an SHA1/memory failures. This only occurs on a very specific repository and can be reproduced stably on two independent laptops. Git mailing list ran out of ideas and for me this looks like some very exotic kernel issue" and bisected the failure to the backport of commit 53a59fc67f97 ("mm: limit mmu_gather batching to fix soft lockups on !CONFIG_PREEMPT"). That commit itself is not actually buggy, but what it does is to make it much more likely to hit the partial TLB invalidation case, since it introduces a new case in tlb_next_batch() that previously only ever happened when running out of memory. The real bug is that the TLB gather virtual memory range setup is subtly buggered. It was introduced in commit 597e1c3580b7 ("mm/mmu_gather: enable tlb flush range in generic mmu_gather"), and the range handling was already fixed at least once in commit e6c495a96ce0 ("mm: fix the TLB range flushed when __tlb_remove_page() runs out of slots"), but that fix was not complete. The problem with the TLB gather virtual address range is that it isn't set up by the initial tlb_gather_mmu() initialization (which didn't get the TLB range information), but it is set up ad-hoc later by the functions that actually flush the TLB. And so any such case that forgot to update the TLB range entries would potentially miss TLB invalidates. Rather than try to figure out exactly which particular ad-hoc range setup was missing (I personally suspect it's the hugetlb case in zap_huge_pmd(), which didn't have the same logic as zap_pte_range() did), this patch just gets rid of the problem at the source: make the TLB range information available to tlb_gather_mmu(), and initialize it when initializing all the other tlb gather fields. This makes the patch larger, but conceptually much simpler. And the end result is much more understandable; even if you want to play games with partial ranges when invalidating the TLB contents in chunks, now the range information is always there, and anybody who doesn't want to bother with it won't introduce subtle bugs. Ben verified that this fixes his problem. Reported-bisected-and-tested-by: Ben Tebulin <tebulin@googlemail.com> Build-testing-by: Stephen Rothwell <sfr@canb.auug.org.au> Build-testing-by: Richard Weinberger <richard.weinberger@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-08-15 22:42:25 +04:00
tlb_gather_mmu(&tlb, mm, start, end);
[PATCH] mm: update_hiwaters just in time update_mem_hiwater has attracted various criticisms, in particular from those concerned with mm scalability. Originally it was called whenever rss or total_vm got raised. Then many of those callsites were replaced by a timer tick call from account_system_time. Now Frank van Maarseveen reports that to be found inadequate. How about this? Works for Frank. Replace update_mem_hiwater, a poor combination of two unrelated ops, by macros update_hiwater_rss and update_hiwater_vm. Don't attempt to keep mm->hiwater_rss up to date at timer tick, nor every time we raise rss (usually by 1): those are hot paths. Do the opposite, update only when about to lower rss (usually by many), or just before final accounting in do_exit. Handle mm->hiwater_vm in the same way, though it's much less of an issue. Demand that whoever collects these hiwater statistics do the work of taking the maximum with rss or total_vm. And there has been no collector of these hiwater statistics in the tree. The new convention needs an example, so match Frank's usage by adding a VmPeak line above VmSize to /proc/<pid>/status, and also a VmHWM line above VmRSS (High-Water-Mark or High-Water-Memory). There was a particular anomaly during mremap move, that hiwater_vm might be captured too high. A fleeting such anomaly remains, but it's quickly corrected now, whereas before it would stick. What locking? None: if the app is racy then these statistics will be racy, it's not worth any overhead to make them exact. But whenever it suits, hiwater_vm is updated under exclusive mmap_sem, and hiwater_rss under page_table_lock (for now) or with preemption disabled (later on): without going to any trouble, minimize the time between reading current values and updating, to minimize those occasions when a racing thread bumps a count up and back down in between. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:16:18 +03:00
update_hiwater_rss(mm);
vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces The VM accounting makes no sense at this level, and half of the callers didn't ever actually use the end result. The only time we want to unaccount the memory is when we actually remove the vma, so do the accounting at that point instead. This simplifies the interfaces (no need to pass down that silly page counter to functions that really don't care), and also makes it much more obvious what is actually going on: we do vm_[un]acct_memory() when adding or removing the vma, not on random page walking. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-07 00:54:06 +04:00
unmap_vmas(&tlb, vma, start, end);
mm: mmu_gather rework Rework the existing mmu_gather infrastructure. The direct purpose of these patches was to allow preemptible mmu_gather, but even without that I think these patches provide an improvement to the status quo. The first 9 patches rework the mmu_gather infrastructure. For review purpose I've split them into generic and per-arch patches with the last of those a generic cleanup. The next patch provides generic RCU page-table freeing, and the followup is a patch converting s390 to use this. I've also got 4 patches from DaveM lined up (not included in this series) that uses this to implement gup_fast() for sparc64. Then there is one patch that extends the generic mmu_gather batching. After that follow the mm preemptibility patches, these make part of the mm a lot more preemptible. It converts i_mmap_lock and anon_vma->lock to mutexes which together with the mmu_gather rework makes mmu_gather preemptible as well. Making i_mmap_lock a mutex also enables a clean-up of the truncate code. This also allows for preemptible mmu_notifiers, something that XPMEM I think wants. Furthermore, it removes the new and universially detested unmap_mutex. This patch: Remove the first obstacle towards a fully preemptible mmu_gather. The current scheme assumes mmu_gather is always done with preemption disabled and uses per-cpu storage for the page batches. Change this to try and allocate a page for batching and in case of failure, use a small on-stack array to make some progress. Preemptible mmu_gather is desired in general and usable once i_mmap_lock becomes a mutex. Doing it before the mutex conversion saves us from having to rework the code by moving the mmu_gather bits inside the pte_lock. Also avoid flushing the tlb batches from under the pte lock, this is useful even without the i_mmap_lock conversion as it significantly reduces pte lock hold times. [akpm@linux-foundation.org: fix comment tpyo] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Tony Luck <tony.luck@intel.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:45 +04:00
free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
mm: allow arch code to control the user page table ceiling On architectures where a pgd entry may be shared between user and kernel (e.g. ARM+LPAE), freeing page tables needs a ceiling other than 0. This patch introduces a generic USER_PGTABLES_CEILING that arch code can override. It is the responsibility of the arch code setting the ceiling to ensure the complete freeing of the page tables (usually in pgd_free()). [catalin.marinas@arm.com: commit log; shift_arg_pages(), asm-generic/pgtables.h changes] Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: <stable@vger.kernel.org> [3.3+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:07:44 +04:00
next ? next->vm_start : USER_PGTABLES_CEILING);
mm: mmu_gather rework Rework the existing mmu_gather infrastructure. The direct purpose of these patches was to allow preemptible mmu_gather, but even without that I think these patches provide an improvement to the status quo. The first 9 patches rework the mmu_gather infrastructure. For review purpose I've split them into generic and per-arch patches with the last of those a generic cleanup. The next patch provides generic RCU page-table freeing, and the followup is a patch converting s390 to use this. I've also got 4 patches from DaveM lined up (not included in this series) that uses this to implement gup_fast() for sparc64. Then there is one patch that extends the generic mmu_gather batching. After that follow the mm preemptibility patches, these make part of the mm a lot more preemptible. It converts i_mmap_lock and anon_vma->lock to mutexes which together with the mmu_gather rework makes mmu_gather preemptible as well. Making i_mmap_lock a mutex also enables a clean-up of the truncate code. This also allows for preemptible mmu_notifiers, something that XPMEM I think wants. Furthermore, it removes the new and universially detested unmap_mutex. This patch: Remove the first obstacle towards a fully preemptible mmu_gather. The current scheme assumes mmu_gather is always done with preemption disabled and uses per-cpu storage for the page batches. Change this to try and allocate a page for batching and in case of failure, use a small on-stack array to make some progress. Preemptible mmu_gather is desired in general and usable once i_mmap_lock becomes a mutex. Doing it before the mutex conversion saves us from having to rework the code by moving the mmu_gather bits inside the pte_lock. Also avoid flushing the tlb batches from under the pte lock, this is useful even without the i_mmap_lock conversion as it significantly reduces pte lock hold times. [akpm@linux-foundation.org: fix comment tpyo] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Tony Luck <tony.luck@intel.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:45 +04:00
tlb_finish_mmu(&tlb, start, end);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/*
* Create a list of vma's touched by the unmap, removing them from the mm's
* vma list as we go..
*/
mm/mmap.c: close race between munmap() and expand_upwards()/downwards() VMA with VM_GROWSDOWN or VM_GROWSUP flag set can change their size under mmap_read_lock(). It can lead to race with __do_munmap(): Thread A Thread B __do_munmap() detach_vmas_to_be_unmapped() mmap_write_downgrade() expand_downwards() vma->vm_start = address; // The VMA now overlaps with // VMAs detached by the Thread A // page fault populates expanded part // of the VMA unmap_region() // Zaps pagetables partly // populated by Thread B Similar race exists for expand_upwards(). The fix is to avoid downgrading mmap_lock in __do_munmap() if detached VMAs are next to VM_GROWSDOWN or VM_GROWSUP VMA. [akpm@linux-foundation.org: s/mmap_sem/mmap_lock/ in comment] Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> [4.20+] Link: http://lkml.kernel.org/r/20200709105309.42495-1-kirill.shutemov@linux.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-24 07:15:11 +03:00
static bool
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, unsigned long end)
{
struct vm_area_struct **insertion_point;
struct vm_area_struct *tail_vma = NULL;
insertion_point = (prev ? &prev->vm_next : &mm->mmap);
mm: make the vma list be doubly linked It's a really simple list, and several of the users want to go backwards in it to find the previous vma. So rather than have to look up the previous entry with 'find_vma_prev()' or something similar, just make it doubly linked instead. Tested-by: Ian Campbell <ijc@hellion.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21 03:24:55 +04:00
vma->vm_prev = NULL;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
do {
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
vma_rb_erase(vma, &mm->mm_rb);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm->map_count--;
tail_vma = vma;
vma = vma->vm_next;
} while (vma && vma->vm_start < end);
*insertion_point = vma;
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
if (vma) {
mm: make the vma list be doubly linked It's a really simple list, and several of the users want to go backwards in it to find the previous vma. So rather than have to look up the previous entry with 'find_vma_prev()' or something similar, just make it doubly linked instead. Tested-by: Ian Campbell <ijc@hellion.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21 03:24:55 +04:00
vma->vm_prev = prev;
mm: augment vma rbtree with rb_subtree_gap Define vma->rb_subtree_gap as the largest gap between any vma in the subtree rooted at that vma, and their predecessor. Or, for a recursive definition, vma->rb_subtree_gap is the max of: - vma->vm_start - vma->vm_prev->vm_end - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and vma->rb.rb_right This will allow get_unmapped_area_* to find a free area of the right size in O(log(N)) time, instead of potentially having to do a linear walk across all the VMAs. Also define mm->highest_vm_end as the vm_end field of the highest vma, so that we can easily check if the following gap is suitable. This does have the potential to make unmapping VMAs more expensive, especially for processes with very large numbers of VMAs, where the VMA rbtree can grow quite deep. Signed-off-by: Michel Lespinasse <walken@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 04:01:38 +04:00
vma_gap_update(vma);
} else
mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 14:03:24 +03:00
mm->highest_vm_end = prev ? vm_end_gap(prev) : 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
tail_vma->vm_next = NULL;
mm: per-thread vma caching This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08 02:37:25 +04:00
/* Kill the cache */
vmacache_invalidate(mm);
mm/mmap.c: close race between munmap() and expand_upwards()/downwards() VMA with VM_GROWSDOWN or VM_GROWSUP flag set can change their size under mmap_read_lock(). It can lead to race with __do_munmap(): Thread A Thread B __do_munmap() detach_vmas_to_be_unmapped() mmap_write_downgrade() expand_downwards() vma->vm_start = address; // The VMA now overlaps with // VMAs detached by the Thread A // page fault populates expanded part // of the VMA unmap_region() // Zaps pagetables partly // populated by Thread B Similar race exists for expand_upwards(). The fix is to avoid downgrading mmap_lock in __do_munmap() if detached VMAs are next to VM_GROWSDOWN or VM_GROWSUP VMA. [akpm@linux-foundation.org: s/mmap_sem/mmap_lock/ in comment] Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> [4.20+] Link: http://lkml.kernel.org/r/20200709105309.42495-1-kirill.shutemov@linux.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-24 07:15:11 +03:00
/*
* Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or
* VM_GROWSUP VMA. Such VMAs can change their size under
* down_read(mmap_lock) and collide with the VMA we are about to unmap.
*/
if (vma && (vma->vm_flags & VM_GROWSDOWN))
return false;
if (prev && (prev->vm_flags & VM_GROWSUP))
return false;
return true;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/*
mm, madvise: fail with ENOMEM when splitting vma will hit max_map_count If madvise(2) advice will result in the underlying vma being split and the number of areas mapped by the process will exceed /proc/sys/vm/max_map_count as a result, return ENOMEM instead of EAGAIN. EAGAIN is returned by madvise(2) when a kernel resource, such as slab, is temporarily unavailable. It indicates that userspace should retry the advice in the near future. This is important for advice such as MADV_DONTNEED which is often used by malloc implementations to free memory back to the system: we really do want to free memory back when madvise(2) returns EAGAIN because slab allocations (for vmas, anon_vmas, or mempolicies) cannot be allocated. Encountering /proc/sys/vm/max_map_count is not a temporary failure, however, so return ENOMEM to indicate this is a more serious issue. A followup patch to the man page will specify this behavior. Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1701241431120.42507@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:47 +03:00
* __split_vma() bypasses sysctl_max_map_count checking. We use this where it
* has already been checked or doesn't make sense to fail.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
mm, madvise: fail with ENOMEM when splitting vma will hit max_map_count If madvise(2) advice will result in the underlying vma being split and the number of areas mapped by the process will exceed /proc/sys/vm/max_map_count as a result, return ENOMEM instead of EAGAIN. EAGAIN is returned by madvise(2) when a kernel resource, such as slab, is temporarily unavailable. It indicates that userspace should retry the advice in the near future. This is important for advice such as MADV_DONTNEED which is often used by malloc implementations to free memory back to the system: we really do want to free memory back when madvise(2) returns EAGAIN because slab allocations (for vmas, anon_vmas, or mempolicies) cannot be allocated. Encountering /proc/sys/vm/max_map_count is not a temporary failure, however, so return ENOMEM to indicate this is a more serious issue. A followup patch to the man page will specify this behavior. Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1701241431120.42507@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:47 +03:00
int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, int new_below)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
struct vm_area_struct *new;
mm/mmap.c: simplify the failure return working flow __split_vma() doesn't need out_err label, neither need initializing err. copy_vma() can return NULL directly when kmem_cache_alloc() fails. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 01:03:38 +03:00
int err;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm, hugetlbfs: introduce ->split() to vm_operations_struct Patch series "device-dax: fix unaligned munmap handling" When device-dax is operating in huge-page mode we want it to behave like hugetlbfs and fail attempts to split vmas into unaligned ranges. It would be messy to teach the munmap path about device-dax alignment constraints in the same (hstate) way that hugetlbfs communicates this constraint. Instead, these patches introduce a new ->split() vm operation. This patch (of 2): The device-dax interface has similar constraints as hugetlbfs in that it requires the munmap path to unmap in huge page aligned units. Rather than add more custom vma handling code in __split_vma() introduce a new vm operation to perform this vma specific check. Link: http://lkml.kernel.org/r/151130418135.4029.6783191281930729710.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-30 03:10:28 +03:00
if (vma->vm_ops && vma->vm_ops->split) {
err = vma->vm_ops->split(vma, addr);
if (err)
return err;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: use helper functions for allocating and freeing vm_area structs The vm_area_struct is one of the most fundamental memory management objects, but the management of it is entirely open-coded evertwhere, ranging from allocation and freeing (using kmem_cache_[z]alloc and kmem_cache_free) to initializing all the fields. We want to unify this in order to end up having some unified initialization of the vmas, and the first step to this is to at least have basic allocation functions. Right now those functions are literally just wrappers around the kmem_cache_*() calls. This is a purely mechanical conversion: # new vma: kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc() # copy old vma kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old) # free vma kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma) to the point where the old vma passed in to the vm_area_dup() function isn't even used yet (because I've left all the old manual initialization alone). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-21 23:48:51 +03:00
new = vm_area_dup(vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (!new)
mm/mmap.c: simplify the failure return working flow __split_vma() doesn't need out_err label, neither need initializing err. copy_vma() can return NULL directly when kmem_cache_alloc() fails. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 01:03:38 +03:00
return -ENOMEM;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (new_below)
new->vm_end = addr;
else {
new->vm_start = addr;
new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
}
mm: mempolicy: turn vma_set_policy() into vma_dup_policy() Simple cleanup. Every user of vma_set_policy() does the same work, this looks a bit annoying imho. And the new trivial helper which does mpol_dup() + vma_set_policy() to simplify the callers. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:20:14 +04:00
err = vma_dup_policy(vma, new);
if (err)
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
goto out_free_vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: fix anon_vma_clone() error treatment Andrew Morton noticed that the error return from anon_vma_clone() was being dropped and replaced with -ENOMEM (which is not itself a bug because the only error return value from anon_vma_clone() is -ENOMEM). I did an audit of callers of anon_vma_clone() and discovered an actual bug where the error return was being lost. In __split_vma(), between Linux 3.11 and 3.12 the code was changed so the err variable is used before the call to anon_vma_clone() and the default initial value of -ENOMEM is overwritten. So a failure of anon_vma_clone() will return success since err at this point is now zero. Below is a patch which fixes this bug and also propagates the error return value from anon_vma_clone() in all cases. Fixes: ef0855d334e1 ("mm: mempolicy: turn vma_set_policy() into vma_dup_policy()") Signed-off-by: Daniel Forrest <dan.forrest@ssec.wisc.edu> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Tim Hartrick <tim@edgecast.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-03 02:59:42 +03:00
err = anon_vma_clone(new, vma);
if (err)
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
goto out_free_mpol;
mm: kill vma flag VM_EXECUTABLE and mm->num_exe_file_vmas Currently the kernel sets mm->exe_file during sys_execve() and then tracks number of vmas with VM_EXECUTABLE flag in mm->num_exe_file_vmas, as soon as this counter drops to zero kernel resets mm->exe_file to NULL. Plus it resets mm->exe_file at last mmput() when mm->mm_users drops to zero. VMA with VM_EXECUTABLE flag appears after mapping file with flag MAP_EXECUTABLE, such vmas can appears only at sys_execve() or after vma splitting, because sys_mmap ignores this flag. Usually binfmt module sets mm->exe_file and mmaps executable vmas with this file, they hold mm->exe_file while task is running. comment from v2.6.25-6245-g925d1c4 ("procfs task exe symlink"), where all this stuff was introduced: > The kernel implements readlink of /proc/pid/exe by getting the file from > the first executable VMA. Then the path to the file is reconstructed and > reported as the result. > > Because of the VMA walk the code is slightly different on nommu systems. > This patch avoids separate /proc/pid/exe code on nommu systems. Instead of > walking the VMAs to find the first executable file-backed VMA we store a > reference to the exec'd file in the mm_struct. > > That reference would prevent the filesystem holding the executable file > from being unmounted even after unmapping the VMAs. So we track the number > of VM_EXECUTABLE VMAs and drop the new reference when the last one is > unmapped. This avoids pinning the mounted filesystem. exe_file's vma accounting is hooked into every file mmap/unmmap and vma split/merge just to fix some hypothetical pinning fs from umounting by mm, which already unmapped all its executable files, but still alive. Seems like currently nobody depends on this behaviour. We can try to remove this logic and keep mm->exe_file until final mmput(). mm->exe_file is still protected with mm->mmap_sem, because we want to change it via new sys_prctl(PR_SET_MM_EXE_FILE). Also via this syscall task can change its mm->exe_file and unpin mountpoint explicitly. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Carsten Otte <cotte@de.ibm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Eric Paris <eparis@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Kentaro Takeda <takedakn@nttdata.co.jp> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Venkatesh Pallipadi <venki@google.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:28:54 +04:00
if (new->vm_file)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
get_file(new->vm_file);
if (new->vm_ops && new->vm_ops->open)
new->vm_ops->open(new);
if (new_below)
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
((addr - new->vm_start) >> PAGE_SHIFT), new);
else
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
/* Success. */
if (!err)
return 0;
/* Clean everything up if vma_adjust failed. */
mmap: check ->vm_ops before dereferencing Check whether the VMA has a vm_ops before calling close, just like we check vm_ops before calling open a few dozen lines higher up in the function. Signed-off-by: Rik van Riel <riel@redhat.com> Reported-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-26 20:33:03 +04:00
if (new->vm_ops && new->vm_ops->close)
new->vm_ops->close(new);
mm: kill vma flag VM_EXECUTABLE and mm->num_exe_file_vmas Currently the kernel sets mm->exe_file during sys_execve() and then tracks number of vmas with VM_EXECUTABLE flag in mm->num_exe_file_vmas, as soon as this counter drops to zero kernel resets mm->exe_file to NULL. Plus it resets mm->exe_file at last mmput() when mm->mm_users drops to zero. VMA with VM_EXECUTABLE flag appears after mapping file with flag MAP_EXECUTABLE, such vmas can appears only at sys_execve() or after vma splitting, because sys_mmap ignores this flag. Usually binfmt module sets mm->exe_file and mmaps executable vmas with this file, they hold mm->exe_file while task is running. comment from v2.6.25-6245-g925d1c4 ("procfs task exe symlink"), where all this stuff was introduced: > The kernel implements readlink of /proc/pid/exe by getting the file from > the first executable VMA. Then the path to the file is reconstructed and > reported as the result. > > Because of the VMA walk the code is slightly different on nommu systems. > This patch avoids separate /proc/pid/exe code on nommu systems. Instead of > walking the VMAs to find the first executable file-backed VMA we store a > reference to the exec'd file in the mm_struct. > > That reference would prevent the filesystem holding the executable file > from being unmounted even after unmapping the VMAs. So we track the number > of VM_EXECUTABLE VMAs and drop the new reference when the last one is > unmapped. This avoids pinning the mounted filesystem. exe_file's vma accounting is hooked into every file mmap/unmmap and vma split/merge just to fix some hypothetical pinning fs from umounting by mm, which already unmapped all its executable files, but still alive. Seems like currently nobody depends on this behaviour. We can try to remove this logic and keep mm->exe_file until final mmput(). mm->exe_file is still protected with mm->mmap_sem, because we want to change it via new sys_prctl(PR_SET_MM_EXE_FILE). Also via this syscall task can change its mm->exe_file and unpin mountpoint explicitly. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Carsten Otte <cotte@de.ibm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Eric Paris <eparis@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Kentaro Takeda <takedakn@nttdata.co.jp> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Venkatesh Pallipadi <venki@google.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:28:54 +04:00
if (new->vm_file)
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
fput(new->vm_file);
mmap: call unlink_anon_vmas() in __split_vma() in case of error If __split_vma fails because of an out of memory condition the anon_vma_chain isn't teardown and freed potentially leading to rmap walks accessing freed vma information plus there's a memleak. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-23 00:05:12 +04:00
unlink_anon_vmas(new);
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
out_free_mpol:
mm: mempolicy: turn vma_set_policy() into vma_dup_policy() Simple cleanup. Every user of vma_set_policy() does the same work, this looks a bit annoying imho. And the new trivial helper which does mpol_dup() + vma_set_policy() to simplify the callers. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:20:14 +04:00
mpol_put(vma_policy(new));
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
out_free_vma:
mm: use helper functions for allocating and freeing vm_area structs The vm_area_struct is one of the most fundamental memory management objects, but the management of it is entirely open-coded evertwhere, ranging from allocation and freeing (using kmem_cache_[z]alloc and kmem_cache_free) to initializing all the fields. We want to unify this in order to end up having some unified initialization of the vmas, and the first step to this is to at least have basic allocation functions. Right now those functions are literally just wrappers around the kmem_cache_*() calls. This is a purely mechanical conversion: # new vma: kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc() # copy old vma kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old) # free vma kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma) to the point where the old vma passed in to the vm_area_dup() function isn't even used yet (because I've left all the old manual initialization alone). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-21 23:48:51 +03:00
vm_area_free(new);
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
return err;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mmap: don't return ENOMEM when mapcount is temporarily exceeded in munmap() On ia64, the following test program exit abnormally, because glibc thread library called abort(). ======================================================== (gdb) bt #0 0xa000000000010620 in __kernel_syscall_via_break () #1 0x20000000003208e0 in raise () from /lib/libc.so.6.1 #2 0x2000000000324090 in abort () from /lib/libc.so.6.1 #3 0x200000000027c3e0 in __deallocate_stack () from /lib/libpthread.so.0 #4 0x200000000027f7c0 in start_thread () from /lib/libpthread.so.0 #5 0x200000000047ef60 in __clone2 () from /lib/libc.so.6.1 ======================================================== The fact is, glibc call munmap() when thread exitng time for freeing stack, and it assume munlock() never fail. However, munmap() often make vma splitting and it with many mapcount make -ENOMEM. Oh well, that's crazy, because stack unmapping never increase mapcount. The maxcount exceeding is only temporary. internal temporary exceeding shouldn't make ENOMEM. This patch does it. test_max_mapcount.c ================================================================== #include<stdio.h> #include<stdlib.h> #include<string.h> #include<pthread.h> #include<errno.h> #include<unistd.h> #define THREAD_NUM 30000 #define MAL_SIZE (8*1024*1024) void *wait_thread(void *args) { void *addr; addr = malloc(MAL_SIZE); sleep(10); return NULL; } void *wait_thread2(void *args) { sleep(60); return NULL; } int main(int argc, char *argv[]) { int i; pthread_t thread[THREAD_NUM], th; int ret, count = 0; pthread_attr_t attr; ret = pthread_attr_init(&attr); if(ret) { perror("pthread_attr_init"); } ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); if(ret) { perror("pthread_attr_setdetachstate"); } for (i = 0; i < THREAD_NUM; i++) { ret = pthread_create(&th, &attr, wait_thread, NULL); if(ret) { fprintf(stderr, "[%d] ", count); perror("pthread_create"); } else { printf("[%d] create OK.\n", count); } count++; ret = pthread_create(&thread[i], &attr, wait_thread2, NULL); if(ret) { fprintf(stderr, "[%d] ", count); perror("pthread_create"); } else { printf("[%d] create OK.\n", count); } count++; } sleep(3600); return 0; } ================================================================== [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 04:57:56 +03:00
/*
* Split a vma into two pieces at address 'addr', a new vma is allocated
* either for the first part or the tail.
*/
int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, int new_below)
{
if (mm->map_count >= sysctl_max_map_count)
return -ENOMEM;
return __split_vma(mm, vma, addr, new_below);
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Munmap is split into 2 main parts -- this part which finds
* what needs doing, and the areas themselves, which do the
* work. This now handles partial unmappings.
* Jeremy Fitzhardinge <jeremy@goop.org>
*/
mm: mremap: downgrade mmap_sem to read when shrinking Other than munmap, mremap might be used to shrink memory mapping too. So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The mremap() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case, so it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. MREMAP_FIXED and MREMAP_MAYMOVE are more complicated to adopt this optimization since they need manipulate vmas after do_munmap(), downgrading mmap_sem may create race window. Simple mapping shrink is the low hanging fruit, and it may cover the most cases of unmap with munmap together. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-2-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:08:50 +03:00
int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
struct list_head *uf, bool downgrade)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
unsigned long end;
[PATCH] freepgt: mpnt to vma cleanup While dabbling here in mmap.c, clean up mysterious "mpnt"s to "vma"s. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:18 +04:00
struct vm_area_struct *vma, *prev, *last;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm/mmap: use offset_in_page macro linux/mm.h provides offset_in_page() macro. Let's use already predefined macro instead of (addr & ~PAGE_MASK). Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:46:54 +03:00
if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -EINVAL;
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
len = PAGE_ALIGN(len);
x86/mpx, mm/core: Fix recursive munmap() corruption This is a bit of a mess, to put it mildly. But, it's a bug that only seems to have showed up in 4.20 but wasn't noticed until now, because nobody uses MPX. MPX has the arch_unmap() hook inside of munmap() because MPX uses bounds tables that protect other areas of memory. When memory is unmapped, there is also a need to unmap the MPX bounds tables. Barring this, unused bounds tables can eat 80% of the address space. But, the recursive do_munmap() that gets called vi arch_unmap() wreaks havoc with __do_munmap()'s state. It can result in freeing populated page tables, accessing bogus VMA state, double-freed VMAs and more. See the "long story" further below for the gory details. To fix this, call arch_unmap() before __do_unmap() has a chance to do anything meaningful. Also, remove the 'vma' argument and force the MPX code to do its own, independent VMA lookup. == UML / unicore32 impact == Remove unused 'vma' argument to arch_unmap(). No functional change. I compile tested this on UML but not unicore32. == powerpc impact == powerpc uses arch_unmap() well to watch for munmap() on the VDSO and zeroes out 'current->mm->context.vdso_base'. Moving arch_unmap() makes this happen earlier in __do_munmap(). But, 'vdso_base' seems to only be used in perf and in the signal delivery that happens near the return to userspace. I can not find any likely impact to powerpc, other than the zeroing happening a little earlier. powerpc does not use the 'vma' argument and is unaffected by its removal. I compile-tested a 64-bit powerpc defconfig. == x86 impact == For the common success case this is functionally identical to what was there before. For the munmap() failure case, it's possible that some MPX tables will be zapped for memory that continues to be in use. But, this is an extraordinarily unlikely scenario and the harm would be that MPX provides no protection since the bounds table got reset (zeroed). I can't imagine anyone doing this: ptr = mmap(); // use ptr ret = munmap(ptr); if (ret) // oh, there was an error, I'll // keep using ptr. Because if you're doing munmap(), you are *done* with the memory. There's probably no good data in there _anyway_. This passes the original reproducer from Richard Biener as well as the existing mpx selftests/. The long story: munmap() has a couple of pieces: 1. Find the affected VMA(s) 2. Split the start/end one(s) if neceesary 3. Pull the VMAs out of the rbtree 4. Actually zap the memory via unmap_region(), including freeing page tables (or queueing them to be freed). 5. Fix up some of the accounting (like fput()) and actually free the VMA itself. This specific ordering was actually introduced by: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") during the 4.20 merge window. The previous __do_munmap() code was actually safe because the only thing after arch_unmap() was remove_vma_list(). arch_unmap() could not see 'vma' in the rbtree because it was detached, so it is not even capable of doing operations unsafe for remove_vma_list()'s use of 'vma'. Richard Biener reported a test that shows this in dmesg: [1216548.787498] BUG: Bad rss-counter state mm:0000000017ce560b idx:1 val:551 [1216548.787500] BUG: non-zero pgtables_bytes on freeing mm: 24576 What triggered this was the recursive do_munmap() called via arch_unmap(). It was freeing page tables that has not been properly zapped. But, the problem was bigger than this. For one, arch_unmap() can free VMAs. But, the calling __do_munmap() has variables that *point* to VMAs and obviously can't handle them just getting freed while the pointer is still in use. I tried a couple of things here. First, I tried to fix the page table freeing problem in isolation, but I then found the VMA issue. I also tried having the MPX code return a flag if it modified the rbtree which would force __do_munmap() to re-walk to restart. That spiralled out of control in complexity pretty fast. Just moving arch_unmap() and accepting that the bonkers failure case might eat some bounds tables seems like the simplest viable fix. This was also reported in the following kernel bugzilla entry: https://bugzilla.kernel.org/show_bug.cgi?id=203123 There are some reports that this commit triggered this bug: dd2283f2605 ("mm: mmap: zap pages with read mmap_sem in munmap") While that commit certainly made the issues easier to hit, I believe the fundamental issue has been with us as long as MPX itself, thus the Fixes: tag below is for one of the original MPX commits. [ mingo: Minor edits to the changelog and the patch. ] Reported-by: Richard Biener <rguenther@suse.de> Reported-by: H.J. Lu <hjl.tools@gmail.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-um@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: stable@vger.kernel.org Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Link: http://lkml.kernel.org/r/20190419194747.5E1AD6DC@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-19 22:47:47 +03:00
end = start + len;
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
if (len == 0)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -EINVAL;
x86/mpx, mm/core: Fix recursive munmap() corruption This is a bit of a mess, to put it mildly. But, it's a bug that only seems to have showed up in 4.20 but wasn't noticed until now, because nobody uses MPX. MPX has the arch_unmap() hook inside of munmap() because MPX uses bounds tables that protect other areas of memory. When memory is unmapped, there is also a need to unmap the MPX bounds tables. Barring this, unused bounds tables can eat 80% of the address space. But, the recursive do_munmap() that gets called vi arch_unmap() wreaks havoc with __do_munmap()'s state. It can result in freeing populated page tables, accessing bogus VMA state, double-freed VMAs and more. See the "long story" further below for the gory details. To fix this, call arch_unmap() before __do_unmap() has a chance to do anything meaningful. Also, remove the 'vma' argument and force the MPX code to do its own, independent VMA lookup. == UML / unicore32 impact == Remove unused 'vma' argument to arch_unmap(). No functional change. I compile tested this on UML but not unicore32. == powerpc impact == powerpc uses arch_unmap() well to watch for munmap() on the VDSO and zeroes out 'current->mm->context.vdso_base'. Moving arch_unmap() makes this happen earlier in __do_munmap(). But, 'vdso_base' seems to only be used in perf and in the signal delivery that happens near the return to userspace. I can not find any likely impact to powerpc, other than the zeroing happening a little earlier. powerpc does not use the 'vma' argument and is unaffected by its removal. I compile-tested a 64-bit powerpc defconfig. == x86 impact == For the common success case this is functionally identical to what was there before. For the munmap() failure case, it's possible that some MPX tables will be zapped for memory that continues to be in use. But, this is an extraordinarily unlikely scenario and the harm would be that MPX provides no protection since the bounds table got reset (zeroed). I can't imagine anyone doing this: ptr = mmap(); // use ptr ret = munmap(ptr); if (ret) // oh, there was an error, I'll // keep using ptr. Because if you're doing munmap(), you are *done* with the memory. There's probably no good data in there _anyway_. This passes the original reproducer from Richard Biener as well as the existing mpx selftests/. The long story: munmap() has a couple of pieces: 1. Find the affected VMA(s) 2. Split the start/end one(s) if neceesary 3. Pull the VMAs out of the rbtree 4. Actually zap the memory via unmap_region(), including freeing page tables (or queueing them to be freed). 5. Fix up some of the accounting (like fput()) and actually free the VMA itself. This specific ordering was actually introduced by: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") during the 4.20 merge window. The previous __do_munmap() code was actually safe because the only thing after arch_unmap() was remove_vma_list(). arch_unmap() could not see 'vma' in the rbtree because it was detached, so it is not even capable of doing operations unsafe for remove_vma_list()'s use of 'vma'. Richard Biener reported a test that shows this in dmesg: [1216548.787498] BUG: Bad rss-counter state mm:0000000017ce560b idx:1 val:551 [1216548.787500] BUG: non-zero pgtables_bytes on freeing mm: 24576 What triggered this was the recursive do_munmap() called via arch_unmap(). It was freeing page tables that has not been properly zapped. But, the problem was bigger than this. For one, arch_unmap() can free VMAs. But, the calling __do_munmap() has variables that *point* to VMAs and obviously can't handle them just getting freed while the pointer is still in use. I tried a couple of things here. First, I tried to fix the page table freeing problem in isolation, but I then found the VMA issue. I also tried having the MPX code return a flag if it modified the rbtree which would force __do_munmap() to re-walk to restart. That spiralled out of control in complexity pretty fast. Just moving arch_unmap() and accepting that the bonkers failure case might eat some bounds tables seems like the simplest viable fix. This was also reported in the following kernel bugzilla entry: https://bugzilla.kernel.org/show_bug.cgi?id=203123 There are some reports that this commit triggered this bug: dd2283f2605 ("mm: mmap: zap pages with read mmap_sem in munmap") While that commit certainly made the issues easier to hit, I believe the fundamental issue has been with us as long as MPX itself, thus the Fixes: tag below is for one of the original MPX commits. [ mingo: Minor edits to the changelog and the patch. ] Reported-by: Richard Biener <rguenther@suse.de> Reported-by: H.J. Lu <hjl.tools@gmail.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-um@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: stable@vger.kernel.org Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Link: http://lkml.kernel.org/r/20190419194747.5E1AD6DC@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-19 22:47:47 +03:00
/*
* arch_unmap() might do unmaps itself. It must be called
* and finish any rbtree manipulation before this code
* runs and also starts to manipulate the rbtree.
*/
arch_unmap(mm, start, end);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Find the first overlapping VMA */
mm: get rid of the most spurious find_vma_prev() users We have some users of this function that date back to before the vma list was doubly linked, and just are silly. These days, you can find the previous vma by just following the vma->vm_prev pointer. In some cases you don't need any find_vma() lookup at all, and in other cases you're better off with the regular "find_vma()" that uses the vma cache front-end lookup. Some "find_vma_prev()" users are still valid, though. For example, in the case of a stack that grows up, it can be the case that we don't find any 'vma' at all (because we're looking up an address that is past the last vma), and that the stack that we want to grow is the 'prev' vma. But that kind of special case aside, we generally should prefer to use 'find_vma()'. Noticed due to a totally unrelated POWER memory corruption bug that just happened to hit in 'find_vma_prev()' and made me go "Hmm - why are we using that function here?". Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-16 11:35:09 +04:00
vma = find_vma(mm, start);
[PATCH] freepgt: mpnt to vma cleanup While dabbling here in mmap.c, clean up mysterious "mpnt"s to "vma"s. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:18 +04:00
if (!vma)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return 0;
mm: get rid of the most spurious find_vma_prev() users We have some users of this function that date back to before the vma list was doubly linked, and just are silly. These days, you can find the previous vma by just following the vma->vm_prev pointer. In some cases you don't need any find_vma() lookup at all, and in other cases you're better off with the regular "find_vma()" that uses the vma cache front-end lookup. Some "find_vma_prev()" users are still valid, though. For example, in the case of a stack that grows up, it can be the case that we don't find any 'vma' at all (because we're looking up an address that is past the last vma), and that the stack that we want to grow is the 'prev' vma. But that kind of special case aside, we generally should prefer to use 'find_vma()'. Noticed due to a totally unrelated POWER memory corruption bug that just happened to hit in 'find_vma_prev()' and made me go "Hmm - why are we using that function here?". Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-16 11:35:09 +04:00
prev = vma->vm_prev;
[PATCH] freepgt: mpnt to vma cleanup While dabbling here in mmap.c, clean up mysterious "mpnt"s to "vma"s. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:18 +04:00
/* we have start < vma->vm_end */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* if it doesn't overlap, we have nothing.. */
[PATCH] freepgt: mpnt to vma cleanup While dabbling here in mmap.c, clean up mysterious "mpnt"s to "vma"s. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:18 +04:00
if (vma->vm_start >= end)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return 0;
/*
* If we need to split any vma, do it now to save pain later.
*
* Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
* unmapped vm_area_struct will remain in use: so lower split_vma
* places tmp vma above, and higher split_vma places tmp vma below.
*/
[PATCH] freepgt: mpnt to vma cleanup While dabbling here in mmap.c, clean up mysterious "mpnt"s to "vma"s. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:18 +04:00
if (start > vma->vm_start) {
mmap: don't return ENOMEM when mapcount is temporarily exceeded in munmap() On ia64, the following test program exit abnormally, because glibc thread library called abort(). ======================================================== (gdb) bt #0 0xa000000000010620 in __kernel_syscall_via_break () #1 0x20000000003208e0 in raise () from /lib/libc.so.6.1 #2 0x2000000000324090 in abort () from /lib/libc.so.6.1 #3 0x200000000027c3e0 in __deallocate_stack () from /lib/libpthread.so.0 #4 0x200000000027f7c0 in start_thread () from /lib/libpthread.so.0 #5 0x200000000047ef60 in __clone2 () from /lib/libc.so.6.1 ======================================================== The fact is, glibc call munmap() when thread exitng time for freeing stack, and it assume munlock() never fail. However, munmap() often make vma splitting and it with many mapcount make -ENOMEM. Oh well, that's crazy, because stack unmapping never increase mapcount. The maxcount exceeding is only temporary. internal temporary exceeding shouldn't make ENOMEM. This patch does it. test_max_mapcount.c ================================================================== #include<stdio.h> #include<stdlib.h> #include<string.h> #include<pthread.h> #include<errno.h> #include<unistd.h> #define THREAD_NUM 30000 #define MAL_SIZE (8*1024*1024) void *wait_thread(void *args) { void *addr; addr = malloc(MAL_SIZE); sleep(10); return NULL; } void *wait_thread2(void *args) { sleep(60); return NULL; } int main(int argc, char *argv[]) { int i; pthread_t thread[THREAD_NUM], th; int ret, count = 0; pthread_attr_t attr; ret = pthread_attr_init(&attr); if(ret) { perror("pthread_attr_init"); } ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); if(ret) { perror("pthread_attr_setdetachstate"); } for (i = 0; i < THREAD_NUM; i++) { ret = pthread_create(&th, &attr, wait_thread, NULL); if(ret) { fprintf(stderr, "[%d] ", count); perror("pthread_create"); } else { printf("[%d] create OK.\n", count); } count++; ret = pthread_create(&thread[i], &attr, wait_thread2, NULL); if(ret) { fprintf(stderr, "[%d] ", count); perror("pthread_create"); } else { printf("[%d] create OK.\n", count); } count++; } sleep(3600); return 0; } ================================================================== [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 04:57:56 +03:00
int error;
/*
* Make sure that map_count on return from munmap() will
* not exceed its limit; but let map_count go just above
* its limit temporarily, to help free resources as expected.
*/
if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
return -ENOMEM;
error = __split_vma(mm, vma, start, 0);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (error)
return error;
[PATCH] freepgt: mpnt to vma cleanup While dabbling here in mmap.c, clean up mysterious "mpnt"s to "vma"s. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:18 +04:00
prev = vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/* Does it split the last one? */
last = find_vma(mm, end);
if (last && end > last->vm_start) {
mmap: don't return ENOMEM when mapcount is temporarily exceeded in munmap() On ia64, the following test program exit abnormally, because glibc thread library called abort(). ======================================================== (gdb) bt #0 0xa000000000010620 in __kernel_syscall_via_break () #1 0x20000000003208e0 in raise () from /lib/libc.so.6.1 #2 0x2000000000324090 in abort () from /lib/libc.so.6.1 #3 0x200000000027c3e0 in __deallocate_stack () from /lib/libpthread.so.0 #4 0x200000000027f7c0 in start_thread () from /lib/libpthread.so.0 #5 0x200000000047ef60 in __clone2 () from /lib/libc.so.6.1 ======================================================== The fact is, glibc call munmap() when thread exitng time for freeing stack, and it assume munlock() never fail. However, munmap() often make vma splitting and it with many mapcount make -ENOMEM. Oh well, that's crazy, because stack unmapping never increase mapcount. The maxcount exceeding is only temporary. internal temporary exceeding shouldn't make ENOMEM. This patch does it. test_max_mapcount.c ================================================================== #include<stdio.h> #include<stdlib.h> #include<string.h> #include<pthread.h> #include<errno.h> #include<unistd.h> #define THREAD_NUM 30000 #define MAL_SIZE (8*1024*1024) void *wait_thread(void *args) { void *addr; addr = malloc(MAL_SIZE); sleep(10); return NULL; } void *wait_thread2(void *args) { sleep(60); return NULL; } int main(int argc, char *argv[]) { int i; pthread_t thread[THREAD_NUM], th; int ret, count = 0; pthread_attr_t attr; ret = pthread_attr_init(&attr); if(ret) { perror("pthread_attr_init"); } ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); if(ret) { perror("pthread_attr_setdetachstate"); } for (i = 0; i < THREAD_NUM; i++) { ret = pthread_create(&th, &attr, wait_thread, NULL); if(ret) { fprintf(stderr, "[%d] ", count); perror("pthread_create"); } else { printf("[%d] create OK.\n", count); } count++; ret = pthread_create(&thread[i], &attr, wait_thread2, NULL); if(ret) { fprintf(stderr, "[%d] ", count); perror("pthread_create"); } else { printf("[%d] create OK.\n", count); } count++; } sleep(3600); return 0; } ================================================================== [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 04:57:56 +03:00
int error = __split_vma(mm, last, end, 1);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (error)
return error;
}
mm/mmap: add inline vma_next() for readability of mmap code There are three places that the next vma is required which uses the same block of code. Replace the block with a function and add comments on what happens in the case where NULL is encountered. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200818154707.2515169-1-Liam.Howlett@Oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 02:14:06 +03:00
vma = vma_next(mm, prev);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
userfaultfd: call userfaultfd_unmap_prep only if __split_vma succeeds A __split_vma is not a worthy event to report, and it's definitely not a unmap so it would be incorrect to report unmap for the whole region to the userfaultfd manager if a __split_vma fails. So only call userfaultfd_unmap_prep after the __vma_splitting is over and do_munmap cannot fail anymore. Also add unlikely because it's better to optimize for the vast majority of apps that aren't using userfaultfd in a non cooperative way. Ideally we should also find a way to eliminate the branch entirely if CONFIG_USERFAULTFD=n, but it would complicate things so stick to unlikely for now. Link: http://lkml.kernel.org/r/20170802165145.22628-5-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Alexey Perevalov <a.perevalov@samsung.com> Cc: Maxime Coquelin <maxime.coquelin@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-07 02:23:53 +03:00
if (unlikely(uf)) {
/*
* If userfaultfd_unmap_prep returns an error the vmas
* will remain splitted, but userland will get a
* highly unexpected error anyway. This is no
* different than the case where the first of the two
* __split_vma fails, but we don't undo the first
* split, despite we could. This is unlikely enough
* failure that it's not worth optimizing it for.
*/
int error = userfaultfd_unmap_prep(vma, start, end, uf);
if (error)
return error;
}
mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:26:50 +04:00
/*
* unlock any mlock()ed ranges before detaching vmas
*/
if (mm->locked_vm) {
struct vm_area_struct *tmp = vma;
while (tmp && tmp->vm_start < end) {
if (tmp->vm_flags & VM_LOCKED) {
mm->locked_vm -= vma_pages(tmp);
munlock_vma_pages_all(tmp);
}
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:26:50 +04:00
tmp = tmp->vm_next;
}
}
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
/* Detach vmas from rbtree */
mm/mmap.c: close race between munmap() and expand_upwards()/downwards() VMA with VM_GROWSDOWN or VM_GROWSUP flag set can change their size under mmap_read_lock(). It can lead to race with __do_munmap(): Thread A Thread B __do_munmap() detach_vmas_to_be_unmapped() mmap_write_downgrade() expand_downwards() vma->vm_start = address; // The VMA now overlaps with // VMAs detached by the Thread A // page fault populates expanded part // of the VMA unmap_region() // Zaps pagetables partly // populated by Thread B Similar race exists for expand_upwards(). The fix is to avoid downgrading mmap_lock in __do_munmap() if detached VMAs are next to VM_GROWSDOWN or VM_GROWSUP VMA. [akpm@linux-foundation.org: s/mmap_sem/mmap_lock/ in comment] Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> [4.20+] Link: http://lkml.kernel.org/r/20200709105309.42495-1-kirill.shutemov@linux.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-24 07:15:11 +03:00
if (!detach_vmas_to_be_unmapped(mm, vma, prev, end))
downgrade = false;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
if (downgrade)
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_write_downgrade(mm);
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
unmap_region(mm, vma, prev, start, end);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Fix up all other VM information */
[PATCH] mm: remove_vma_list consolidation unmap_vma doesn't amount to much, let's put it inside unmap_vma_list. Except it doesn't unmap anything, unmap_region just did the unmapping: rename it to remove_vma_list. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:56 +03:00
remove_vma_list(mm, vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
return downgrade ? 1 : 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
struct list_head *uf)
{
return __do_munmap(mm, start, len, uf, false);
}
static int __vm_munmap(unsigned long start, size_t len, bool downgrade)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
int ret;
kill mm argument of vm_munmap() it's always current->mm Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-04-21 05:57:04 +04:00
struct mm_struct *mm = current->mm;
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
LIST_HEAD(uf);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
if (mmap_write_lock_killable(mm))
mm: make vm_munmap killable Almost all current users of vm_munmap are ignoring the return value and so they do not handle potential error. This means that some VMAs might stay behind. This patch doesn't try to solve those potential problems. Quite contrary it adds a new failure mode by using down_write_killable in vm_munmap. This should be safer than other failure modes, though, because the process is guaranteed to die as soon as it leaves the kernel and exit_mmap will clean the whole address space. This will help in the OOM conditions when the oom victim might be stuck waiting for the mmap_sem for write which in turn can block oom_reaper which relies on the mmap_sem for read to make a forward progress and reclaim the address space of the victim. Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-24 02:25:33 +03:00
return -EINTR;
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
ret = __do_munmap(mm, start, len, &uf, downgrade);
/*
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* Returning 1 indicates mmap_lock is downgraded.
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
* But 1 is not legal return value of vm_munmap() and munmap(), reset
* it to 0 before return.
*/
if (ret == 1) {
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_read_unlock(mm);
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
ret = 0;
} else
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_write_unlock(mm);
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
userfaultfd_unmap_complete(mm, &uf);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return ret;
}
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
int vm_munmap(unsigned long start, size_t len)
{
return __vm_munmap(start, len, false);
}
VM: add "vm_munmap()" helper function Like the vm_brk() function, this is the same as "do_munmap()", except it does the VM locking for the caller. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-21 03:20:01 +04:00
EXPORT_SYMBOL(vm_munmap);
SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
{
mm: untag user pointers in mmap/munmap/mremap/brk There isn't a good reason to differentiate between the user address space layout modification syscalls and the other memory permission/attributes ones (e.g. mprotect, madvise) w.r.t. the tagged address ABI. Untag the user addresses on entry to these functions. Link: http://lkml.kernel.org/r/20190821164730.47450-2-catalin.marinas@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Andrey Konovalov <andreyknvl@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Szabolcs Nagy <szabolcs.nagy@arm.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Dave P Martin <Dave.Martin@arm.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 02:49:04 +03:00
addr = untagged_addr(addr);
VM: add "vm_munmap()" helper function Like the vm_brk() function, this is the same as "do_munmap()", except it does the VM locking for the caller. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-21 03:20:01 +04:00
profile_munmap(addr);
mm: mmap: zap pages with read mmap_sem in munmap Patch series "mm: zap pages with read mmap_sem in munmap for large mapping", v11. Background: Recently, when we ran some vm scalability tests on machines with large memory, we ran into a couple of mmap_sem scalability issues when unmapping large memory space, please refer to https://lkml.org/lkml/2017/12/14/733 and https://lkml.org/lkml/2018/2/20/576. History: Then akpm suggested to unmap large mapping section by section and drop mmap_sem at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784). V1 patch series was submitted to the mailing list per Andrew's suggestion (see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great feedback and suggestions. Then this topic was discussed on LSFMM summit 2018. In the summit, Michal Hocko suggested (also in the v1 patches review) to try "two phases" approach. Zapping pages with read mmap_sem, then doing via cleanup with write mmap_sem (for discussion detail, see https://lwn.net/Articles/753269/) Approach: Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, we can't call MADV_DONTNEED directly, since there are two major drawbacks: * The unexpected state from PF if it wins the race in the middle of munmap. It may return zero page, instead of the content or SIGSEGV. * Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which is a showstopper from akpm But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by falling back to regular do_munmap() with exclusive mmap_sem held in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. So, uprobe unmap will not be handled by the regular path. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. This patch (of 3): When running some mmap/munmap scalability tests with large memory (i.e. > 300GB), the below hung task issue may happen occasionally. INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0 ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040 00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000 Call Trace: [<ffffffff817154d0>] ? __schedule+0x250/0x730 [<ffffffff817159e6>] schedule+0x36/0x80 [<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150 [<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30 [<ffffffff81717db0>] down_read+0x20/0x40 [<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0 [<ffffffff81253c95>] ? do_filp_open+0xa5/0x100 [<ffffffff81241d87>] __vfs_read+0x37/0x150 [<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0 [<ffffffff81242266>] vfs_read+0x96/0x130 [<ffffffff812437b5>] SyS_read+0x55/0xc0 [<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5 It is because munmap holds mmap_sem exclusively from very beginning to all the way down to the end, and doesn't release it in the middle. When unmapping large mapping, it may take long time (take ~18 seconds to unmap 320GB mapping with every single page mapped on an idle machine). Zapping pages is the most time consuming part, according to the suggestion from Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas. But, some part may need write mmap_sem, for example, vma splitting. So, the design is as follows: acquire write mmap_sem lookup vmas (find and split vmas) deal with special mappings detach vmas downgrade_write zap pages free page tables release mmap_sem The vm events with read mmap_sem may come in during page zapping, but since vmas have been detached before, they, i.e. page fault, gup, etc, will not be able to find valid vma, then just return SIGSEGV or -EFAULT as expected. If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special mappings. They will be handled by without downgrading mmap_sem in this patch since they may update vm flags. But, with the "detach vmas first" approach, the vmas have been detached when vm flags are updated, so it sounds safe to update vm flags with read mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be handled by using the optimized path in the following separate patches for bisectable sake. Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES). However it is fine to have false-positive MMF_RECALC_UPROBES according to uprobes developer. With the "detach vmas first" approach we don't have to re-acquire mmap_sem again to clean up vmas to avoid race window which might get the address space changed since downgrade_write() doesn't release the lock to lead regression, which simply downgrades to read lock. And, since the lock acquire/release cost is managed to the minimum and almost as same as before, the optimization could be extended to any size of mapping without incurring significant penalty to small mappings. For the time being, just do this in munmap syscall path. Other vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain intact due to some implementation difficulties since they acquire write mmap_sem from very beginning and hold it until the end, do_munmap() might be called in the middle. But, the optimized do_munmap would like to be called without mmap_sem held so that we can do the optimization. So, if we want to do the similar optimization for mmap/mremap path, I'm afraid we would have to redesign them. mremap might be called on very large area depending on the usecases, the optimization to it will be considered in the future. With the patches, exclusive mmap_sem hold time when munmap a 80GB address space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level from second. munmap_test-15002 [008] 594.380138: funcgraph_entry: | __vm_munmap() { munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us | unmap_region(); munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us | } Here the execution time of unmap_region() is used to evaluate the time of holding read mmap_sem, then the remaining time is used with holding exclusive lock. [1] https://lwn.net/Articles/753269/ Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 01:07:11 +03:00
return __vm_munmap(addr, len, true);
VM: add "vm_munmap()" helper function Like the vm_brk() function, this is the same as "do_munmap()", except it does the VM locking for the caller. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-21 03:20:01 +04:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
/*
* Emulation of deprecated remap_file_pages() syscall.
*/
SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
unsigned long, prot, unsigned long, pgoff, unsigned long, flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long populate = 0;
unsigned long ret = -EINVAL;
struct file *file;
docs/vm: rename documentation files to .rst Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-03-21 22:22:47 +03:00
pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.rst.\n",
mm: coalesce split strings Kernel style prefers a single string over split strings when the string is 'user-visible'. Miscellanea: - Add a missing newline - Realign arguments Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Tejun Heo <tj@kernel.org> [percpu] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-18 00:19:47 +03:00
current->comm, current->pid);
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
if (prot)
return ret;
start = start & PAGE_MASK;
size = size & PAGE_MASK;
if (start + size <= start)
return ret;
/* Does pgoff wrap? */
if (pgoff + (size >> PAGE_SHIFT) < pgoff)
return ret;
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
if (mmap_write_lock_killable(mm))
mm: make mmap_sem for write waits killable for mm syscalls This is a follow up work for oom_reaper [1]. As the async OOM killing depends on oom_sem for read we would really appreciate if a holder for write didn't stood in the way. This patchset is changing many of down_write calls to be killable to help those cases when the writer is blocked and waiting for readers to release the lock and so help __oom_reap_task to process the oom victim. Most of the patches are really trivial because the lock is help from a shallow syscall paths where we can return EINTR trivially and allow the current task to die (note that EINTR will never get to the userspace as the task has fatal signal pending). Others seem to be easy as well as the callers are already handling fatal errors and bail and return to userspace which should be sufficient to handle the failure gracefully. I am not familiar with all those code paths so a deeper review is really appreciated. As this work is touching more areas which are not directly connected I have tried to keep the CC list as small as possible and people who I believed would be familiar are CCed only to the specific patches (all should have received the cover though). This patchset is based on linux-next and it depends on down_write_killable for rw_semaphores which got merged into tip locking/rwsem branch and it is merged into this next tree. I guess it would be easiest to route these patches via mmotm because of the dependency on the tip tree but if respective maintainers prefer other way I have no objections. I haven't covered all the mmap_write(mm->mmap_sem) instances here $ git grep "down_write(.*\<mmap_sem\>)" next/master | wc -l 98 $ git grep "down_write(.*\<mmap_sem\>)" | wc -l 62 I have tried to cover those which should be relatively easy to review in this series because this alone should be a nice improvement. Other places can be changed on top. [0] http://lkml.kernel.org/r/1456752417-9626-1-git-send-email-mhocko@kernel.org [1] http://lkml.kernel.org/r/1452094975-551-1-git-send-email-mhocko@kernel.org [2] http://lkml.kernel.org/r/1456750705-7141-1-git-send-email-mhocko@kernel.org This patch (of 18): This is the first step in making mmap_sem write waiters killable. It focuses on the trivial ones which are taking the lock early after entering the syscall and they are not changing state before. Therefore it is very easy to change them to use down_write_killable and immediately return with -EINTR. This will allow the waiter to pass away without blocking the mmap_sem which might be required to make a forward progress. E.g. the oom reaper will need the lock for reading to dismantle the OOM victim address space. The only tricky function in this patch is vm_mmap_pgoff which has many call sites via vm_mmap. To reduce the risk keep vm_mmap with the original non-killable semantic for now. vm_munmap callers do not bother checking the return value so open code it into the munmap syscall path for now for simplicity. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-24 02:25:27 +03:00
return -EINTR;
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
vma = find_vma(mm, start);
if (!vma || !(vma->vm_flags & VM_SHARED))
goto out;
mm: fix regression in remap_file_pages() emulation Grazvydas Ignotas has reported a regression in remap_file_pages() emulation. Testcase: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define SIZE (4096 * 3) int main(int argc, char **argv) { unsigned long *p; long i; p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; if (remap_file_pages(p, 4096, 0, 1, 0)) { perror("remap_file_pages"); return -1; } if (remap_file_pages(p, 4096 * 2, 0, 1, 0)) { perror("remap_file_pages"); return -1; } assert(p[0] == 1); munmap(p, SIZE); return 0; } The second remap_file_pages() fails with -EINVAL. The reason is that remap_file_pages() emulation assumes that the target vma covers whole area we want to over map. That assumption is broken by first remap_file_pages() call: it split the area into two vma. The solution is to check next adjacent vmas, if they map the same file with the same flags. Fixes: c8d78c1823f4 ("mm: replace remap_file_pages() syscall with emulation") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Grazvydas Ignotas <notasas@gmail.com> Tested-by: Grazvydas Ignotas <notasas@gmail.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-18 00:11:15 +03:00
if (start < vma->vm_start)
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
goto out;
mm: fix regression in remap_file_pages() emulation Grazvydas Ignotas has reported a regression in remap_file_pages() emulation. Testcase: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define SIZE (4096 * 3) int main(int argc, char **argv) { unsigned long *p; long i; p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; if (remap_file_pages(p, 4096, 0, 1, 0)) { perror("remap_file_pages"); return -1; } if (remap_file_pages(p, 4096 * 2, 0, 1, 0)) { perror("remap_file_pages"); return -1; } assert(p[0] == 1); munmap(p, SIZE); return 0; } The second remap_file_pages() fails with -EINVAL. The reason is that remap_file_pages() emulation assumes that the target vma covers whole area we want to over map. That assumption is broken by first remap_file_pages() call: it split the area into two vma. The solution is to check next adjacent vmas, if they map the same file with the same flags. Fixes: c8d78c1823f4 ("mm: replace remap_file_pages() syscall with emulation") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Grazvydas Ignotas <notasas@gmail.com> Tested-by: Grazvydas Ignotas <notasas@gmail.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-18 00:11:15 +03:00
if (start + size > vma->vm_end) {
struct vm_area_struct *next;
for (next = vma->vm_next; next; next = next->vm_next) {
/* hole between vmas ? */
if (next->vm_start != next->vm_prev->vm_end)
goto out;
if (next->vm_file != vma->vm_file)
goto out;
if (next->vm_flags != vma->vm_flags)
goto out;
if (start + size <= next->vm_end)
break;
}
if (!next)
goto out;
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
}
prot |= vma->vm_flags & VM_READ ? PROT_READ : 0;
prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0;
prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0;
flags &= MAP_NONBLOCK;
flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
if (vma->vm_flags & VM_LOCKED) {
mm: fix regression in remap_file_pages() emulation Grazvydas Ignotas has reported a regression in remap_file_pages() emulation. Testcase: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define SIZE (4096 * 3) int main(int argc, char **argv) { unsigned long *p; long i; p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; if (remap_file_pages(p, 4096, 0, 1, 0)) { perror("remap_file_pages"); return -1; } if (remap_file_pages(p, 4096 * 2, 0, 1, 0)) { perror("remap_file_pages"); return -1; } assert(p[0] == 1); munmap(p, SIZE); return 0; } The second remap_file_pages() fails with -EINVAL. The reason is that remap_file_pages() emulation assumes that the target vma covers whole area we want to over map. That assumption is broken by first remap_file_pages() call: it split the area into two vma. The solution is to check next adjacent vmas, if they map the same file with the same flags. Fixes: c8d78c1823f4 ("mm: replace remap_file_pages() syscall with emulation") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Grazvydas Ignotas <notasas@gmail.com> Tested-by: Grazvydas Ignotas <notasas@gmail.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-18 00:11:15 +03:00
struct vm_area_struct *tmp;
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
flags |= MAP_LOCKED;
mm: fix regression in remap_file_pages() emulation Grazvydas Ignotas has reported a regression in remap_file_pages() emulation. Testcase: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define SIZE (4096 * 3) int main(int argc, char **argv) { unsigned long *p; long i; p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; if (remap_file_pages(p, 4096, 0, 1, 0)) { perror("remap_file_pages"); return -1; } if (remap_file_pages(p, 4096 * 2, 0, 1, 0)) { perror("remap_file_pages"); return -1; } assert(p[0] == 1); munmap(p, SIZE); return 0; } The second remap_file_pages() fails with -EINVAL. The reason is that remap_file_pages() emulation assumes that the target vma covers whole area we want to over map. That assumption is broken by first remap_file_pages() call: it split the area into two vma. The solution is to check next adjacent vmas, if they map the same file with the same flags. Fixes: c8d78c1823f4 ("mm: replace remap_file_pages() syscall with emulation") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Grazvydas Ignotas <notasas@gmail.com> Tested-by: Grazvydas Ignotas <notasas@gmail.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-18 00:11:15 +03:00
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
/* drop PG_Mlocked flag for over-mapped range */
mm: fix regression in remap_file_pages() emulation Grazvydas Ignotas has reported a regression in remap_file_pages() emulation. Testcase: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define SIZE (4096 * 3) int main(int argc, char **argv) { unsigned long *p; long i; p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; if (remap_file_pages(p, 4096, 0, 1, 0)) { perror("remap_file_pages"); return -1; } if (remap_file_pages(p, 4096 * 2, 0, 1, 0)) { perror("remap_file_pages"); return -1; } assert(p[0] == 1); munmap(p, SIZE); return 0; } The second remap_file_pages() fails with -EINVAL. The reason is that remap_file_pages() emulation assumes that the target vma covers whole area we want to over map. That assumption is broken by first remap_file_pages() call: it split the area into two vma. The solution is to check next adjacent vmas, if they map the same file with the same flags. Fixes: c8d78c1823f4 ("mm: replace remap_file_pages() syscall with emulation") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Grazvydas Ignotas <notasas@gmail.com> Tested-by: Grazvydas Ignotas <notasas@gmail.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-18 00:11:15 +03:00
for (tmp = vma; tmp->vm_start >= start + size;
tmp = tmp->vm_next) {
thp, mlock: do not mlock PTE-mapped file huge pages As with anon THP, we only mlock file huge pages if we can prove that the page is not mapped with PTE. This way we can avoid mlock leak into non-mlocked vma on split. We rely on PageDoubleMap() under lock_page() to check if the the page may be PTE mapped. PG_double_map is set by page_add_file_rmap() when the page mapped with PTEs. Link: http://lkml.kernel.org/r/1466021202-61880-21-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27 01:25:53 +03:00
/*
* Split pmd and munlock page on the border
* of the range.
*/
vma_adjust_trans_huge(tmp, start, start + size, 0);
mm: fix regression in remap_file_pages() emulation Grazvydas Ignotas has reported a regression in remap_file_pages() emulation. Testcase: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define SIZE (4096 * 3) int main(int argc, char **argv) { unsigned long *p; long i; p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; if (remap_file_pages(p, 4096, 0, 1, 0)) { perror("remap_file_pages"); return -1; } if (remap_file_pages(p, 4096 * 2, 0, 1, 0)) { perror("remap_file_pages"); return -1; } assert(p[0] == 1); munmap(p, SIZE); return 0; } The second remap_file_pages() fails with -EINVAL. The reason is that remap_file_pages() emulation assumes that the target vma covers whole area we want to over map. That assumption is broken by first remap_file_pages() call: it split the area into two vma. The solution is to check next adjacent vmas, if they map the same file with the same flags. Fixes: c8d78c1823f4 ("mm: replace remap_file_pages() syscall with emulation") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Grazvydas Ignotas <notasas@gmail.com> Tested-by: Grazvydas Ignotas <notasas@gmail.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-18 00:11:15 +03:00
munlock_vma_pages_range(tmp,
max(tmp->vm_start, start),
min(tmp->vm_end, start + size));
}
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
}
file = get_file(vma->vm_file);
mm: remove unnecessary wrapper function do_mmap_pgoff() The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db7f82 ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:23:37 +03:00
ret = do_mmap(vma->vm_file, start, size,
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
prot, flags, pgoff, &populate, NULL);
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
fput(file);
out:
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_write_unlock(mm);
mm: replace remap_file_pages() syscall with emulation remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:46 +03:00
if (populate)
mm_populate(ret, populate);
if (!IS_ERR_VALUE(ret))
ret = 0;
return ret;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* this is really a simplified "do_mmap". it only handles
* anonymous maps. eventually we may be able to do some
* brk-specific accounting here.
*/
mm: do not bug_on on incorrect length in __mm_populate() syzbot has noticed that a specially crafted library can easily hit VM_BUG_ON in __mm_populate kernel BUG at mm/gup.c:1242! invalid opcode: 0000 [#1] SMP CPU: 2 PID: 9667 Comm: a.out Not tainted 4.18.0-rc3 #644 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 RIP: 0010:__mm_populate+0x1e2/0x1f0 Code: 55 d0 65 48 33 14 25 28 00 00 00 89 d8 75 21 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 18 f1 ff 0f 0b e8 6e 18 f1 ff <0f> 0b 31 db eb c9 e8 93 06 e0 ff 0f 1f 00 55 48 89 e5 53 48 89 fb Call Trace: vm_brk_flags+0xc3/0x100 vm_brk+0x1f/0x30 load_elf_library+0x281/0x2e0 __ia32_sys_uselib+0x170/0x1e0 do_fast_syscall_32+0xca/0x420 entry_SYSENTER_compat+0x70/0x7f The reason is that the length of the new brk is not page aligned when we try to populate the it. There is no reason to bug on that though. do_brk_flags already aligns the length properly so the mapping is expanded as it should. All we need is to tell mm_populate about it. Besides that there is absolutely no reason to to bug_on in the first place. The worst thing that could happen is that the last page wouldn't get populated and that is far from putting system into an inconsistent state. Fix the issue by moving the length sanitization code from do_brk_flags up to vm_brk_flags. The only other caller of do_brk_flags is brk syscall entry and it makes sure to provide the proper length so t here is no need for sanitation and so we can use do_brk_flags without it. Also remove the bogus BUG_ONs. [osalvador@techadventures.net: fix up vm_brk_flags s@request@len@] Link: http://lkml.kernel.org/r/20180706090217.GI32658@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: syzbot <syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-14 02:59:20 +03:00
static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long flags, struct list_head *uf)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm/mmap.c: whitespace fixes Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:26:29 +04:00
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma, *prev;
struct rb_node **rb_link, *rb_parent;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
pgoff_t pgoff = addr >> PAGE_SHIFT;
[PATCH] IA64,sparc: local DoS with corrupted ELFs This prevents cross-region mappings on IA64 and SPARC which could lead to system crash. They were correctly trapped for normal mmap() calls, but not for the kernel internal calls generated by executable loading. This code just moves the architecture-specific cross-region checks into an arch-specific "arch_mmap_check()" macro, and defines that for the architectures that needed it (ia64, sparc and sparc64). Architectures that don't have any special requirements can just ignore the new cross-region check, since the mmap() code will just notice on its own when the macro isn't defined. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Kirill Korotaev <dev@openvz.org> Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> [ Cleaned up to not affect architectures that don't need it ] Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-07 14:17:04 +04:00
int error;
mm/mmap.c: use IS_ERR_VALUE to check return value of get_unmapped_area get_unmapped_area() returns an address or -errno on failure. Historically we have checked for the failure by offset_in_page() which is correct but quite hard to read. Newer code started using IS_ERR_VALUE which is much easier to read. Convert remaining users of offset_in_page as well. [mhocko@suse.com: rewrite changelog] [mhocko@kernel.org: fix mremap.c and uprobes.c sites also] Link: http://lkml.kernel.org/r/20191012102512.28051-1-pugaowei@gmail.com Signed-off-by: Gaowei Pu <pugaowei@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Rik van Riel <riel@surriel.com> Cc: Qian Cai <cai@lca.pw> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 04:51:03 +03:00
unsigned long mapped_addr;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
powerpc: do not make the entire heap executable On 32-bit powerpc the ELF PLT sections of binaries (built with --bss-plt, or with a toolchain which defaults to it) look like this: [17] .sbss NOBITS 0002aff8 01aff8 000014 00 WA 0 0 4 [18] .plt NOBITS 0002b00c 01aff8 000084 00 WAX 0 0 4 [19] .bss NOBITS 0002b090 01aff8 0000a4 00 WA 0 0 4 Which results in an ELF load header: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align LOAD 0x019c70 0x00029c70 0x00029c70 0x01388 0x014c4 RWE 0x10000 This is all correct, the load region containing the PLT is marked as executable. Note that the PLT starts at 0002b00c but the file mapping ends at 0002aff8, so the PLT falls in the 0 fill section described by the load header, and after a page boundary. Unfortunately the generic ELF loader ignores the X bit in the load headers when it creates the 0 filled non-file backed mappings. It assumes all of these mappings are RW BSS sections, which is not the case for PPC. gcc/ld has an option (--secure-plt) to not do this, this is said to incur a small performance penalty. Currently, to support 32-bit binaries with PLT in BSS kernel maps *entire brk area* with executable rights for all binaries, even --secure-plt ones. Stop doing that. Teach the ELF loader to check the X bit in the relevant load header and create 0 filled anonymous mappings that are executable if the load header requests that. Test program showing the difference in /proc/$PID/maps: int main() { char buf[16*1024]; char *p = malloc(123); /* make "[heap]" mapping appear */ int fd = open("/proc/self/maps", O_RDONLY); int len = read(fd, buf, sizeof(buf)); write(1, buf, len); printf("%p\n", p); return 0; } Compiled using: gcc -mbss-plt -m32 -Os test.c -otest Unpatched ppc64 kernel: 00100000-00120000 r-xp 00000000 00:00 0 [vdso] 0fe10000-0ffd0000 r-xp 00000000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffd0000-0ffe0000 r--p 001b0000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffe0000-0fff0000 rw-p 001c0000 fd:00 67898094 /usr/lib/libc-2.17.so 10000000-10010000 r-xp 00000000 fd:00 100674505 /home/user/test 10010000-10020000 r--p 00000000 fd:00 100674505 /home/user/test 10020000-10030000 rw-p 00010000 fd:00 100674505 /home/user/test 10690000-106c0000 rwxp 00000000 00:00 0 [heap] f7f70000-f7fa0000 r-xp 00000000 fd:00 67898089 /usr/lib/ld-2.17.so f7fa0000-f7fb0000 r--p 00020000 fd:00 67898089 /usr/lib/ld-2.17.so f7fb0000-f7fc0000 rw-p 00030000 fd:00 67898089 /usr/lib/ld-2.17.so ffa90000-ffac0000 rw-p 00000000 00:00 0 [stack] 0x10690008 Patched ppc64 kernel: 00100000-00120000 r-xp 00000000 00:00 0 [vdso] 0fe10000-0ffd0000 r-xp 00000000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffd0000-0ffe0000 r--p 001b0000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffe0000-0fff0000 rw-p 001c0000 fd:00 67898094 /usr/lib/libc-2.17.so 10000000-10010000 r-xp 00000000 fd:00 100674505 /home/user/test 10010000-10020000 r--p 00000000 fd:00 100674505 /home/user/test 10020000-10030000 rw-p 00010000 fd:00 100674505 /home/user/test 10180000-101b0000 rw-p 00000000 00:00 0 [heap] ^^^^ this has changed f7c60000-f7c90000 r-xp 00000000 fd:00 67898089 /usr/lib/ld-2.17.so f7c90000-f7ca0000 r--p 00020000 fd:00 67898089 /usr/lib/ld-2.17.so f7ca0000-f7cb0000 rw-p 00030000 fd:00 67898089 /usr/lib/ld-2.17.so ff860000-ff890000 rw-p 00000000 00:00 0 [stack] 0x10180008 The patch was originally posted in 2012 by Jason Gunthorpe and apparently ignored: https://lkml.org/lkml/2012/9/30/138 Lightly run-tested. Link: http://lkml.kernel.org/r/20161215131950.23054-1-dvlasenk@redhat.com Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Florian Weimer <fweimer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-23 02:45:16 +03:00
/* Until we need other flags, refuse anything except VM_EXEC. */
if ((flags & (~VM_EXEC)) != 0)
return -EINVAL;
flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
[PATCH] IA64,sparc: local DoS with corrupted ELFs This prevents cross-region mappings on IA64 and SPARC which could lead to system crash. They were correctly trapped for normal mmap() calls, but not for the kernel internal calls generated by executable loading. This code just moves the architecture-specific cross-region checks into an arch-specific "arch_mmap_check()" macro, and defines that for the architectures that needed it (ia64, sparc and sparc64). Architectures that don't have any special requirements can just ignore the new cross-region check, since the mmap() code will just notice on its own when the macro isn't defined. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Kirill Korotaev <dev@openvz.org> Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> [ Cleaned up to not affect architectures that don't need it ] Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-07 14:17:04 +04:00
mm/mmap.c: use IS_ERR_VALUE to check return value of get_unmapped_area get_unmapped_area() returns an address or -errno on failure. Historically we have checked for the failure by offset_in_page() which is correct but quite hard to read. Newer code started using IS_ERR_VALUE which is much easier to read. Convert remaining users of offset_in_page as well. [mhocko@suse.com: rewrite changelog] [mhocko@kernel.org: fix mremap.c and uprobes.c sites also] Link: http://lkml.kernel.org/r/20191012102512.28051-1-pugaowei@gmail.com Signed-off-by: Gaowei Pu <pugaowei@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Rik van Riel <riel@surriel.com> Cc: Qian Cai <cai@lca.pw> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 04:51:03 +03:00
mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
if (IS_ERR_VALUE(mapped_addr))
return mapped_addr;
[PATCH] IA64,sparc: local DoS with corrupted ELFs This prevents cross-region mappings on IA64 and SPARC which could lead to system crash. They were correctly trapped for normal mmap() calls, but not for the kernel internal calls generated by executable loading. This code just moves the architecture-specific cross-region checks into an arch-specific "arch_mmap_check()" macro, and defines that for the architectures that needed it (ia64, sparc and sparc64). Architectures that don't have any special requirements can just ignore the new cross-region check, since the mmap() code will just notice on its own when the macro isn't defined. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Kirill Korotaev <dev@openvz.org> Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> [ Cleaned up to not affect architectures that don't need it ] Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-07 14:17:04 +04:00
mm/mmap.c: add mlock_future_check() helper Both do_brk and do_mmap_pgoff verify that we are actually capable of locking future pages if the corresponding VM_LOCKED flags are used. Encapsulate this logic into a single mlock_future_check() helper function. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-22 03:49:15 +04:00
error = mlock_future_check(mm, mm->def_flags, len);
if (error)
return error;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm/mmap: add inline munmap_vma_range() for code readability There are two locations that have a block of code for munmapping a vma range. Change those two locations to use a function and add meaningful comments about what happens to the arguments, which was unclear in the previous code. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200818154707.2515169-2-Liam.Howlett@Oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 02:14:09 +03:00
/* Clear old maps, set up prev, rb_link, rb_parent, and uf */
if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
return -ENOMEM;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Check against address space limits *after* clearing old maps... */
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -ENOMEM;
if (mm->map_count > sysctl_max_map_count)
return -ENOMEM;
mm: collapse security_vm_enough_memory() variants into a single function Collapse security_vm_enough_memory() variants into a single function. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Morris <jmorris@namei.org>
2012-02-13 07:58:52 +04:00
if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
return -ENOMEM;
/* Can we just expand an old private anonymous mapping? */
mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:26:50 +04:00
vma = vma_merge(mm, prev, addr, addr + len, flags,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
NULL, NULL, pgoff, NULL, NULL_VM_UFFD_CTX);
mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:26:50 +04:00
if (vma)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
goto out;
/*
* create a vma struct for an anonymous mapping
*/
mm: make vm_area_alloc() initialize core fields Like vm_area_dup(), it initializes the anon_vma_chain head, and the basic mm pointer. The rest of the fields end up being different for different users, although the plan is to also initialize the 'vm_ops' field to a dummy entry. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-22 01:24:03 +03:00
vma = vm_area_alloc(mm);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (!vma) {
vm_unacct_memory(len >> PAGE_SHIFT);
return -ENOMEM;
}
mm: fix vma_is_anonymous() false-positives vma_is_anonymous() relies on ->vm_ops being NULL to detect anonymous VMA. This is unreliable as ->mmap may not set ->vm_ops. False-positive vma_is_anonymous() may lead to crashes: next ffff8801ce5e7040 prev ffff8801d20eca50 mm ffff88019c1e13c0 prot 27 anon_vma ffff88019680cdd8 vm_ops 0000000000000000 pgoff 0 file ffff8801b2ec2d00 private_data 0000000000000000 flags: 0xff(read|write|exec|shared|mayread|maywrite|mayexec|mayshare) ------------[ cut here ]------------ kernel BUG at mm/memory.c:1422! invalid opcode: 0000 [#1] SMP KASAN CPU: 0 PID: 18486 Comm: syz-executor3 Not tainted 4.18.0-rc3+ #136 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:zap_pmd_range mm/memory.c:1421 [inline] RIP: 0010:zap_pud_range mm/memory.c:1466 [inline] RIP: 0010:zap_p4d_range mm/memory.c:1487 [inline] RIP: 0010:unmap_page_range+0x1c18/0x2220 mm/memory.c:1508 Call Trace: unmap_single_vma+0x1a0/0x310 mm/memory.c:1553 zap_page_range_single+0x3cc/0x580 mm/memory.c:1644 unmap_mapping_range_vma mm/memory.c:2792 [inline] unmap_mapping_range_tree mm/memory.c:2813 [inline] unmap_mapping_pages+0x3a7/0x5b0 mm/memory.c:2845 unmap_mapping_range+0x48/0x60 mm/memory.c:2880 truncate_pagecache+0x54/0x90 mm/truncate.c:800 truncate_setsize+0x70/0xb0 mm/truncate.c:826 simple_setattr+0xe9/0x110 fs/libfs.c:409 notify_change+0xf13/0x10f0 fs/attr.c:335 do_truncate+0x1ac/0x2b0 fs/open.c:63 do_sys_ftruncate+0x492/0x560 fs/open.c:205 __do_sys_ftruncate fs/open.c:215 [inline] __se_sys_ftruncate fs/open.c:213 [inline] __x64_sys_ftruncate+0x59/0x80 fs/open.c:213 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Reproducer: #include <stdio.h> #include <stddef.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/ioctl.h> #include <sys/mman.h> #include <unistd.h> #include <fcntl.h> #define KCOV_INIT_TRACE _IOR('c', 1, unsigned long) #define KCOV_ENABLE _IO('c', 100) #define KCOV_DISABLE _IO('c', 101) #define COVER_SIZE (1024<<10) #define KCOV_TRACE_PC 0 #define KCOV_TRACE_CMP 1 int main(int argc, char **argv) { int fd; unsigned long *cover; system("mount -t debugfs none /sys/kernel/debug"); fd = open("/sys/kernel/debug/kcov", O_RDWR); ioctl(fd, KCOV_INIT_TRACE, COVER_SIZE); cover = mmap(NULL, COVER_SIZE * sizeof(unsigned long), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); munmap(cover, COVER_SIZE * sizeof(unsigned long)); cover = mmap(NULL, COVER_SIZE * sizeof(unsigned long), PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); memset(cover, 0, COVER_SIZE * sizeof(unsigned long)); ftruncate(fd, 3UL << 20); return 0; } This can be fixed by assigning anonymous VMAs own vm_ops and not relying on it being NULL. If ->mmap() failed to set ->vm_ops, mmap_region() will set it to dummy_vm_ops. This way we will have non-NULL ->vm_ops for all VMAs. Link: http://lkml.kernel.org/r/20180724121139.62570-4-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: syzbot+3f84280d52be9b7083cc@syzkaller.appspotmail.com Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-27 02:37:35 +03:00
vma_set_anonymous(vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
vma->vm_start = addr;
vma->vm_end = addr + len;
vma->vm_pgoff = pgoff;
vma->vm_flags = flags;
setup vma->vm_page_prot by vm_get_page_prot() This patch uses vm_get_page_prot() to setup vma->vm_page_prot. Though inside vm_get_page_prot() the protection flags is AND with (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED), it does not hurt correct code. Signed-off-by: Coly Li <coyli@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 10:39:15 +04:00
vma->vm_page_prot = vm_get_page_prot(flags);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
vma_link(mm, vma, prev, rb_link, rb_parent);
out:
perf: Add non-exec mmap() tracking Add the capacility to track data mmap()s. This can be used together with PERF_SAMPLE_ADDR for data profiling. Signed-off-by: Anton Blanchard <anton@samba.org> [Updated code for stable perf ABI] Signed-off-by: Eric B Munson <ebmunson@us.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1274193049-25997-1-git-send-email-ebmunson@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-18 18:30:49 +04:00
perf_event_mmap(vma);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm->total_vm += len >> PAGE_SHIFT;
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
mm->data_vm += len >> PAGE_SHIFT;
mm: use mm_populate() when adjusting brk with MCL_FUTURE in effect Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:40 +04:00
if (flags & VM_LOCKED)
mm->locked_vm += (len >> PAGE_SHIFT);
mm: track vma changes with VM_SOFTDIRTY bit Pavel reported that in case if vma area get unmapped and then mapped (or expanded) in-place, the soft dirty tracker won't be able to recognize this situation since it works on pte level and ptes are get zapped on unmap, loosing soft dirty bit of course. So to resolve this situation we need to track actions on vma level, there VM_SOFTDIRTY flag comes in. When new vma area created (or old expanded) we set this bit, and keep it here until application calls for clearing soft dirty bit. Thus when user space application track memory changes now it can detect if vma area is renewed. Reported-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Matt Mackall <mpm@selenic.com> Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:22:24 +04:00
vma->vm_flags |= VM_SOFTDIRTY;
mm: remove more IS_ERR_VALUE abuses The do_brk() and vm_brk() return value was "unsigned long" and returned the starting address on success, and an error value on failure. The reasons are entirely historical, and go back to it basically behaving like the mmap() interface does. However, nobody actually wanted that interface, and it causes totally pointless IS_ERR_VALUE() confusion. What every single caller actually wants is just the simpler integer return of zero for success and negative error number on failure. So just convert to that much clearer and more common calling convention, and get rid of all the IS_ERR_VALUE() uses wrt vm_brk(). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 01:57:31 +03:00
return 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
mm: do not bug_on on incorrect length in __mm_populate() syzbot has noticed that a specially crafted library can easily hit VM_BUG_ON in __mm_populate kernel BUG at mm/gup.c:1242! invalid opcode: 0000 [#1] SMP CPU: 2 PID: 9667 Comm: a.out Not tainted 4.18.0-rc3 #644 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 RIP: 0010:__mm_populate+0x1e2/0x1f0 Code: 55 d0 65 48 33 14 25 28 00 00 00 89 d8 75 21 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 18 f1 ff 0f 0b e8 6e 18 f1 ff <0f> 0b 31 db eb c9 e8 93 06 e0 ff 0f 1f 00 55 48 89 e5 53 48 89 fb Call Trace: vm_brk_flags+0xc3/0x100 vm_brk+0x1f/0x30 load_elf_library+0x281/0x2e0 __ia32_sys_uselib+0x170/0x1e0 do_fast_syscall_32+0xca/0x420 entry_SYSENTER_compat+0x70/0x7f The reason is that the length of the new brk is not page aligned when we try to populate the it. There is no reason to bug on that though. do_brk_flags already aligns the length properly so the mapping is expanded as it should. All we need is to tell mm_populate about it. Besides that there is absolutely no reason to to bug_on in the first place. The worst thing that could happen is that the last page wouldn't get populated and that is far from putting system into an inconsistent state. Fix the issue by moving the length sanitization code from do_brk_flags up to vm_brk_flags. The only other caller of do_brk_flags is brk syscall entry and it makes sure to provide the proper length so t here is no need for sanitation and so we can use do_brk_flags without it. Also remove the bogus BUG_ONs. [osalvador@techadventures.net: fix up vm_brk_flags s@request@len@] Link: http://lkml.kernel.org/r/20180706090217.GI32658@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: syzbot <syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-14 02:59:20 +03:00
int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
VM: add "vm_brk()" helper function It does the same thing as "do_brk()", except it handles the VM locking too. It turns out that all external callers want that anyway, so we can make do_brk() static to just mm/mmap.c while at it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-21 02:35:40 +04:00
{
struct mm_struct *mm = current->mm;
mm: do not bug_on on incorrect length in __mm_populate() syzbot has noticed that a specially crafted library can easily hit VM_BUG_ON in __mm_populate kernel BUG at mm/gup.c:1242! invalid opcode: 0000 [#1] SMP CPU: 2 PID: 9667 Comm: a.out Not tainted 4.18.0-rc3 #644 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 RIP: 0010:__mm_populate+0x1e2/0x1f0 Code: 55 d0 65 48 33 14 25 28 00 00 00 89 d8 75 21 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 18 f1 ff 0f 0b e8 6e 18 f1 ff <0f> 0b 31 db eb c9 e8 93 06 e0 ff 0f 1f 00 55 48 89 e5 53 48 89 fb Call Trace: vm_brk_flags+0xc3/0x100 vm_brk+0x1f/0x30 load_elf_library+0x281/0x2e0 __ia32_sys_uselib+0x170/0x1e0 do_fast_syscall_32+0xca/0x420 entry_SYSENTER_compat+0x70/0x7f The reason is that the length of the new brk is not page aligned when we try to populate the it. There is no reason to bug on that though. do_brk_flags already aligns the length properly so the mapping is expanded as it should. All we need is to tell mm_populate about it. Besides that there is absolutely no reason to to bug_on in the first place. The worst thing that could happen is that the last page wouldn't get populated and that is far from putting system into an inconsistent state. Fix the issue by moving the length sanitization code from do_brk_flags up to vm_brk_flags. The only other caller of do_brk_flags is brk syscall entry and it makes sure to provide the proper length so t here is no need for sanitation and so we can use do_brk_flags without it. Also remove the bogus BUG_ONs. [osalvador@techadventures.net: fix up vm_brk_flags s@request@len@] Link: http://lkml.kernel.org/r/20180706090217.GI32658@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: syzbot <syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-14 02:59:20 +03:00
unsigned long len;
mm: remove more IS_ERR_VALUE abuses The do_brk() and vm_brk() return value was "unsigned long" and returned the starting address on success, and an error value on failure. The reasons are entirely historical, and go back to it basically behaving like the mmap() interface does. However, nobody actually wanted that interface, and it causes totally pointless IS_ERR_VALUE() confusion. What every single caller actually wants is just the simpler integer return of zero for success and negative error number on failure. So just convert to that much clearer and more common calling convention, and get rid of all the IS_ERR_VALUE() uses wrt vm_brk(). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 01:57:31 +03:00
int ret;
mm: use mm_populate() when adjusting brk with MCL_FUTURE in effect Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:40 +04:00
bool populate;
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
LIST_HEAD(uf);
VM: add "vm_brk()" helper function It does the same thing as "do_brk()", except it handles the VM locking too. It turns out that all external callers want that anyway, so we can make do_brk() static to just mm/mmap.c while at it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-21 02:35:40 +04:00
mm: do not bug_on on incorrect length in __mm_populate() syzbot has noticed that a specially crafted library can easily hit VM_BUG_ON in __mm_populate kernel BUG at mm/gup.c:1242! invalid opcode: 0000 [#1] SMP CPU: 2 PID: 9667 Comm: a.out Not tainted 4.18.0-rc3 #644 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 RIP: 0010:__mm_populate+0x1e2/0x1f0 Code: 55 d0 65 48 33 14 25 28 00 00 00 89 d8 75 21 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 18 f1 ff 0f 0b e8 6e 18 f1 ff <0f> 0b 31 db eb c9 e8 93 06 e0 ff 0f 1f 00 55 48 89 e5 53 48 89 fb Call Trace: vm_brk_flags+0xc3/0x100 vm_brk+0x1f/0x30 load_elf_library+0x281/0x2e0 __ia32_sys_uselib+0x170/0x1e0 do_fast_syscall_32+0xca/0x420 entry_SYSENTER_compat+0x70/0x7f The reason is that the length of the new brk is not page aligned when we try to populate the it. There is no reason to bug on that though. do_brk_flags already aligns the length properly so the mapping is expanded as it should. All we need is to tell mm_populate about it. Besides that there is absolutely no reason to to bug_on in the first place. The worst thing that could happen is that the last page wouldn't get populated and that is far from putting system into an inconsistent state. Fix the issue by moving the length sanitization code from do_brk_flags up to vm_brk_flags. The only other caller of do_brk_flags is brk syscall entry and it makes sure to provide the proper length so t here is no need for sanitation and so we can use do_brk_flags without it. Also remove the bogus BUG_ONs. [osalvador@techadventures.net: fix up vm_brk_flags s@request@len@] Link: http://lkml.kernel.org/r/20180706090217.GI32658@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: syzbot <syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-14 02:59:20 +03:00
len = PAGE_ALIGN(request);
if (len < request)
return -ENOMEM;
if (!len)
return 0;
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
if (mmap_write_lock_killable(mm))
mm: make vm_brk killable Now that all the callers handle vm_brk failure we can change it wait for mmap_sem killable to help oom_reaper to not get blocked just because vm_brk gets blocked behind mmap_sem readers. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-24 02:25:42 +03:00
return -EINTR;
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
ret = do_brk_flags(addr, len, flags, &uf);
mm: use mm_populate() when adjusting brk with MCL_FUTURE in effect Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:40 +04:00
populate = ((mm->def_flags & VM_LOCKED) != 0);
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_write_unlock(mm);
userfaultfd: non-cooperative: add event for memory unmaps When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:58:22 +03:00
userfaultfd_unmap_complete(mm, &uf);
mm: remove more IS_ERR_VALUE abuses The do_brk() and vm_brk() return value was "unsigned long" and returned the starting address on success, and an error value on failure. The reasons are entirely historical, and go back to it basically behaving like the mmap() interface does. However, nobody actually wanted that interface, and it causes totally pointless IS_ERR_VALUE() confusion. What every single caller actually wants is just the simpler integer return of zero for success and negative error number on failure. So just convert to that much clearer and more common calling convention, and get rid of all the IS_ERR_VALUE() uses wrt vm_brk(). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 01:57:31 +03:00
if (populate && !ret)
mm: use mm_populate() when adjusting brk with MCL_FUTURE in effect Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Greg Ungerer <gregungerer@westnet.com.au> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:32:40 +04:00
mm_populate(addr, len);
VM: add "vm_brk()" helper function It does the same thing as "do_brk()", except it handles the VM locking too. It turns out that all external callers want that anyway, so we can make do_brk() static to just mm/mmap.c while at it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-21 02:35:40 +04:00
return ret;
}
powerpc: do not make the entire heap executable On 32-bit powerpc the ELF PLT sections of binaries (built with --bss-plt, or with a toolchain which defaults to it) look like this: [17] .sbss NOBITS 0002aff8 01aff8 000014 00 WA 0 0 4 [18] .plt NOBITS 0002b00c 01aff8 000084 00 WAX 0 0 4 [19] .bss NOBITS 0002b090 01aff8 0000a4 00 WA 0 0 4 Which results in an ELF load header: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align LOAD 0x019c70 0x00029c70 0x00029c70 0x01388 0x014c4 RWE 0x10000 This is all correct, the load region containing the PLT is marked as executable. Note that the PLT starts at 0002b00c but the file mapping ends at 0002aff8, so the PLT falls in the 0 fill section described by the load header, and after a page boundary. Unfortunately the generic ELF loader ignores the X bit in the load headers when it creates the 0 filled non-file backed mappings. It assumes all of these mappings are RW BSS sections, which is not the case for PPC. gcc/ld has an option (--secure-plt) to not do this, this is said to incur a small performance penalty. Currently, to support 32-bit binaries with PLT in BSS kernel maps *entire brk area* with executable rights for all binaries, even --secure-plt ones. Stop doing that. Teach the ELF loader to check the X bit in the relevant load header and create 0 filled anonymous mappings that are executable if the load header requests that. Test program showing the difference in /proc/$PID/maps: int main() { char buf[16*1024]; char *p = malloc(123); /* make "[heap]" mapping appear */ int fd = open("/proc/self/maps", O_RDONLY); int len = read(fd, buf, sizeof(buf)); write(1, buf, len); printf("%p\n", p); return 0; } Compiled using: gcc -mbss-plt -m32 -Os test.c -otest Unpatched ppc64 kernel: 00100000-00120000 r-xp 00000000 00:00 0 [vdso] 0fe10000-0ffd0000 r-xp 00000000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffd0000-0ffe0000 r--p 001b0000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffe0000-0fff0000 rw-p 001c0000 fd:00 67898094 /usr/lib/libc-2.17.so 10000000-10010000 r-xp 00000000 fd:00 100674505 /home/user/test 10010000-10020000 r--p 00000000 fd:00 100674505 /home/user/test 10020000-10030000 rw-p 00010000 fd:00 100674505 /home/user/test 10690000-106c0000 rwxp 00000000 00:00 0 [heap] f7f70000-f7fa0000 r-xp 00000000 fd:00 67898089 /usr/lib/ld-2.17.so f7fa0000-f7fb0000 r--p 00020000 fd:00 67898089 /usr/lib/ld-2.17.so f7fb0000-f7fc0000 rw-p 00030000 fd:00 67898089 /usr/lib/ld-2.17.so ffa90000-ffac0000 rw-p 00000000 00:00 0 [stack] 0x10690008 Patched ppc64 kernel: 00100000-00120000 r-xp 00000000 00:00 0 [vdso] 0fe10000-0ffd0000 r-xp 00000000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffd0000-0ffe0000 r--p 001b0000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffe0000-0fff0000 rw-p 001c0000 fd:00 67898094 /usr/lib/libc-2.17.so 10000000-10010000 r-xp 00000000 fd:00 100674505 /home/user/test 10010000-10020000 r--p 00000000 fd:00 100674505 /home/user/test 10020000-10030000 rw-p 00010000 fd:00 100674505 /home/user/test 10180000-101b0000 rw-p 00000000 00:00 0 [heap] ^^^^ this has changed f7c60000-f7c90000 r-xp 00000000 fd:00 67898089 /usr/lib/ld-2.17.so f7c90000-f7ca0000 r--p 00020000 fd:00 67898089 /usr/lib/ld-2.17.so f7ca0000-f7cb0000 rw-p 00030000 fd:00 67898089 /usr/lib/ld-2.17.so ff860000-ff890000 rw-p 00000000 00:00 0 [stack] 0x10180008 The patch was originally posted in 2012 by Jason Gunthorpe and apparently ignored: https://lkml.org/lkml/2012/9/30/138 Lightly run-tested. Link: http://lkml.kernel.org/r/20161215131950.23054-1-dvlasenk@redhat.com Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Florian Weimer <fweimer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-23 02:45:16 +03:00
EXPORT_SYMBOL(vm_brk_flags);
int vm_brk(unsigned long addr, unsigned long len)
{
return vm_brk_flags(addr, len, 0);
}
VM: add "vm_brk()" helper function It does the same thing as "do_brk()", except it handles the VM locking too. It turns out that all external callers want that anyway, so we can make do_brk() static to just mm/mmap.c while at it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-21 02:35:40 +04:00
EXPORT_SYMBOL(vm_brk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/* Release all mmaps. */
void exit_mmap(struct mm_struct *mm)
{
mm: mmu_gather rework Rework the existing mmu_gather infrastructure. The direct purpose of these patches was to allow preemptible mmu_gather, but even without that I think these patches provide an improvement to the status quo. The first 9 patches rework the mmu_gather infrastructure. For review purpose I've split them into generic and per-arch patches with the last of those a generic cleanup. The next patch provides generic RCU page-table freeing, and the followup is a patch converting s390 to use this. I've also got 4 patches from DaveM lined up (not included in this series) that uses this to implement gup_fast() for sparc64. Then there is one patch that extends the generic mmu_gather batching. After that follow the mm preemptibility patches, these make part of the mm a lot more preemptible. It converts i_mmap_lock and anon_vma->lock to mutexes which together with the mmu_gather rework makes mmu_gather preemptible as well. Making i_mmap_lock a mutex also enables a clean-up of the truncate code. This also allows for preemptible mmu_notifiers, something that XPMEM I think wants. Furthermore, it removes the new and universially detested unmap_mutex. This patch: Remove the first obstacle towards a fully preemptible mmu_gather. The current scheme assumes mmu_gather is always done with preemption disabled and uses per-cpu storage for the page batches. Change this to try and allocate a page for batching and in case of failure, use a small on-stack array to make some progress. Preemptible mmu_gather is desired in general and usable once i_mmap_lock becomes a mutex. Doing it before the mutex conversion saves us from having to rework the code by moving the mmu_gather bits inside the pte_lock. Also avoid flushing the tlb batches from under the pte lock, this is useful even without the i_mmap_lock conversion as it significantly reduces pte lock hold times. [akpm@linux-foundation.org: fix comment tpyo] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Tony Luck <tony.luck@intel.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 04:11:45 +04:00
struct mmu_gather tlb;
mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:26:50 +04:00
struct vm_area_struct *vma;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
unsigned long nr_accounted = 0;
[PATCH] x86: PARAVIRT: add hooks to intercept mm creation and destruction Add hooks to allow a paravirt implementation to track the lifetime of an mm. Paravirtualization requires three hooks, but only two are needed in common code. They are: arch_dup_mmap, which is called when a new mmap is created at fork arch_exit_mmap, which is called when the last process reference to an mm is dropped, which typically happens on exit and exec. The third hook is activate_mm, which is called from the arch-specific activate_mm() macro/function, and so doesn't need stub versions for other architectures. It's called when an mm is first used. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: linux-arch@vger.kernel.org Cc: James Bottomley <James.Bottomley@SteelEye.com> Acked-by: Ingo Molnar <mingo@elte.hu>
2007-05-02 21:27:14 +04:00
/* mm's last user has gone, and its about to be pulled down */
mmu-notifiers: core With KVM/GFP/XPMEM there isn't just the primary CPU MMU pointing to pages. There are secondary MMUs (with secondary sptes and secondary tlbs) too. sptes in the kvm case are shadow pagetables, but when I say spte in mmu-notifier context, I mean "secondary pte". In GRU case there's no actual secondary pte and there's only a secondary tlb because the GRU secondary MMU has no knowledge about sptes and every secondary tlb miss event in the MMU always generates a page fault that has to be resolved by the CPU (this is not the case of KVM where the a secondary tlb miss will walk sptes in hardware and it will refill the secondary tlb transparently to software if the corresponding spte is present). The same way zap_page_range has to invalidate the pte before freeing the page, the spte (and secondary tlb) must also be invalidated before any page is freed and reused. Currently we take a page_count pin on every page mapped by sptes, but that means the pages can't be swapped whenever they're mapped by any spte because they're part of the guest working set. Furthermore a spte unmap event can immediately lead to a page to be freed when the pin is released (so requiring the same complex and relatively slow tlb_gather smp safe logic we have in zap_page_range and that can be avoided completely if the spte unmap event doesn't require an unpin of the page previously mapped in the secondary MMU). The mmu notifiers allow kvm/GRU/XPMEM to attach to the tsk->mm and know when the VM is swapping or freeing or doing anything on the primary MMU so that the secondary MMU code can drop sptes before the pages are freed, avoiding all page pinning and allowing 100% reliable swapping of guest physical address space. Furthermore it avoids the code that teardown the mappings of the secondary MMU, to implement a logic like tlb_gather in zap_page_range that would require many IPI to flush other cpu tlbs, for each fixed number of spte unmapped. To make an example: if what happens on the primary MMU is a protection downgrade (from writeable to wrprotect) the secondary MMU mappings will be invalidated, and the next secondary-mmu-page-fault will call get_user_pages and trigger a do_wp_page through get_user_pages if it called get_user_pages with write=1, and it'll re-establishing an updated spte or secondary-tlb-mapping on the copied page. Or it will setup a readonly spte or readonly tlb mapping if it's a guest-read, if it calls get_user_pages with write=0. This is just an example. This allows to map any page pointed by any pte (and in turn visible in the primary CPU MMU), into a secondary MMU (be it a pure tlb like GRU, or an full MMU with both sptes and secondary-tlb like the shadow-pagetable layer with kvm), or a remote DMA in software like XPMEM (hence needing of schedule in XPMEM code to send the invalidate to the remote node, while no need to schedule in kvm/gru as it's an immediate event like invalidating primary-mmu pte). At least for KVM without this patch it's impossible to swap guests reliably. And having this feature and removing the page pin allows several other optimizations that simplify life considerably. Dependencies: 1) mm_take_all_locks() to register the mmu notifier when the whole VM isn't doing anything with "mm". This allows mmu notifier users to keep track if the VM is in the middle of the invalidate_range_begin/end critical section with an atomic counter incraese in range_begin and decreased in range_end. No secondary MMU page fault is allowed to map any spte or secondary tlb reference, while the VM is in the middle of range_begin/end as any page returned by get_user_pages in that critical section could later immediately be freed without any further ->invalidate_page notification (invalidate_range_begin/end works on ranges and ->invalidate_page isn't called immediately before freeing the page). To stop all page freeing and pagetable overwrites the mmap_sem must be taken in write mode and all other anon_vma/i_mmap locks must be taken too. 2) It'd be a waste to add branches in the VM if nobody could possibly run KVM/GRU/XPMEM on the kernel, so mmu notifiers will only enabled if CONFIG_KVM=m/y. In the current kernel kvm won't yet take advantage of mmu notifiers, but this already allows to compile a KVM external module against a kernel with mmu notifiers enabled and from the next pull from kvm.git we'll start using them. And GRU/XPMEM will also be able to continue the development by enabling KVM=m in their config, until they submit all GRU/XPMEM GPLv2 code to the mainline kernel. Then they can also enable MMU_NOTIFIERS in the same way KVM does it (even if KVM=n). This guarantees nobody selects MMU_NOTIFIER=y if KVM and GRU and XPMEM are all =n. The mmu_notifier_register call can fail because mm_take_all_locks may be interrupted by a signal and return -EINTR. Because mmu_notifier_reigster is used when a driver startup, a failure can be gracefully handled. Here an example of the change applied to kvm to register the mmu notifiers. Usually when a driver startups other allocations are required anyway and -ENOMEM failure paths exists already. struct kvm *kvm_arch_create_vm(void) { struct kvm *kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL); + int err; if (!kvm) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&kvm->arch.active_mmu_pages); + kvm->arch.mmu_notifier.ops = &kvm_mmu_notifier_ops; + err = mmu_notifier_register(&kvm->arch.mmu_notifier, current->mm); + if (err) { + kfree(kvm); + return ERR_PTR(err); + } + return kvm; } mmu_notifier_unregister returns void and it's reliable. The patch also adds a few needed but missing includes that would prevent kernel to compile after these changes on non-x86 archs (x86 didn't need them by luck). [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix mm/filemap_xip.c build] [akpm@linux-foundation.org: fix mm/mmu_notifier.c build] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:29 +04:00
mmu_notifier_release(mm);
[PATCH] x86: PARAVIRT: add hooks to intercept mm creation and destruction Add hooks to allow a paravirt implementation to track the lifetime of an mm. Paravirtualization requires three hooks, but only two are needed in common code. They are: arch_dup_mmap, which is called when a new mmap is created at fork arch_exit_mmap, which is called when the last process reference to an mm is dropped, which typically happens on exit and exec. The third hook is activate_mm, which is called from the arch-specific activate_mm() macro/function, and so doesn't need stub versions for other architectures. It's called when an mm is first used. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: linux-arch@vger.kernel.org Cc: James Bottomley <James.Bottomley@SteelEye.com> Acked-by: Ingo Molnar <mingo@elte.hu>
2007-05-02 21:27:14 +04:00
mm, oom: fix concurrent munlock and oom reaper unmap, v3 Since exit_mmap() is done without the protection of mm->mmap_sem, it is possible for the oom reaper to concurrently operate on an mm until MMF_OOM_SKIP is set. This allows munlock_vma_pages_all() to concurrently run while the oom reaper is operating on a vma. Since munlock_vma_pages_range() depends on clearing VM_LOCKED from vm_flags before actually doing the munlock to determine if any other vmas are locking the same memory, the check for VM_LOCKED in the oom reaper is racy. This is especially noticeable on architectures such as powerpc where clearing a huge pmd requires serialize_against_pte_lookup(). If the pmd is zapped by the oom reaper during follow_page_mask() after the check for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a kernel oops. Fix this by manually freeing all possible memory from the mm before doing the munlock and then setting MMF_OOM_SKIP. The oom reaper can not run on the mm anymore so the munlock is safe to do in exit_mmap(). It also matches the logic that the oom reaper currently uses for determining when to set MMF_OOM_SKIP itself, so there's no new risk of excessive oom killing. This issue fixes CVE-2018-1000200. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com Fixes: 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently") Signed-off-by: David Rientjes <rientjes@google.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-12 02:02:04 +03:00
if (unlikely(mm_is_oom_victim(mm))) {
/*
* Manually reap the mm to free as much memory as possible.
* Then, as the oom reaper does, set MMF_OOM_SKIP to disregard
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* this mm from further consideration. Taking mm->mmap_lock for
mm, oom: fix concurrent munlock and oom reaper unmap, v3 Since exit_mmap() is done without the protection of mm->mmap_sem, it is possible for the oom reaper to concurrently operate on an mm until MMF_OOM_SKIP is set. This allows munlock_vma_pages_all() to concurrently run while the oom reaper is operating on a vma. Since munlock_vma_pages_range() depends on clearing VM_LOCKED from vm_flags before actually doing the munlock to determine if any other vmas are locking the same memory, the check for VM_LOCKED in the oom reaper is racy. This is especially noticeable on architectures such as powerpc where clearing a huge pmd requires serialize_against_pte_lookup(). If the pmd is zapped by the oom reaper during follow_page_mask() after the check for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a kernel oops. Fix this by manually freeing all possible memory from the mm before doing the munlock and then setting MMF_OOM_SKIP. The oom reaper can not run on the mm anymore so the munlock is safe to do in exit_mmap(). It also matches the logic that the oom reaper currently uses for determining when to set MMF_OOM_SKIP itself, so there's no new risk of excessive oom killing. This issue fixes CVE-2018-1000200. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com Fixes: 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently") Signed-off-by: David Rientjes <rientjes@google.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-12 02:02:04 +03:00
* write after setting MMF_OOM_SKIP will guarantee that the oom
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* reaper will not run on this mm again after mmap_lock is
mm, oom: fix concurrent munlock and oom reaper unmap, v3 Since exit_mmap() is done without the protection of mm->mmap_sem, it is possible for the oom reaper to concurrently operate on an mm until MMF_OOM_SKIP is set. This allows munlock_vma_pages_all() to concurrently run while the oom reaper is operating on a vma. Since munlock_vma_pages_range() depends on clearing VM_LOCKED from vm_flags before actually doing the munlock to determine if any other vmas are locking the same memory, the check for VM_LOCKED in the oom reaper is racy. This is especially noticeable on architectures such as powerpc where clearing a huge pmd requires serialize_against_pte_lookup(). If the pmd is zapped by the oom reaper during follow_page_mask() after the check for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a kernel oops. Fix this by manually freeing all possible memory from the mm before doing the munlock and then setting MMF_OOM_SKIP. The oom reaper can not run on the mm anymore so the munlock is safe to do in exit_mmap(). It also matches the logic that the oom reaper currently uses for determining when to set MMF_OOM_SKIP itself, so there's no new risk of excessive oom killing. This issue fixes CVE-2018-1000200. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com Fixes: 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently") Signed-off-by: David Rientjes <rientjes@google.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-12 02:02:04 +03:00
* dropped.
*
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* Nothing can be holding mm->mmap_lock here and the above call
mm, oom: fix concurrent munlock and oom reaper unmap, v3 Since exit_mmap() is done without the protection of mm->mmap_sem, it is possible for the oom reaper to concurrently operate on an mm until MMF_OOM_SKIP is set. This allows munlock_vma_pages_all() to concurrently run while the oom reaper is operating on a vma. Since munlock_vma_pages_range() depends on clearing VM_LOCKED from vm_flags before actually doing the munlock to determine if any other vmas are locking the same memory, the check for VM_LOCKED in the oom reaper is racy. This is especially noticeable on architectures such as powerpc where clearing a huge pmd requires serialize_against_pte_lookup(). If the pmd is zapped by the oom reaper during follow_page_mask() after the check for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a kernel oops. Fix this by manually freeing all possible memory from the mm before doing the munlock and then setting MMF_OOM_SKIP. The oom reaper can not run on the mm anymore so the munlock is safe to do in exit_mmap(). It also matches the logic that the oom reaper currently uses for determining when to set MMF_OOM_SKIP itself, so there's no new risk of excessive oom killing. This issue fixes CVE-2018-1000200. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com Fixes: 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently") Signed-off-by: David Rientjes <rientjes@google.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-12 02:02:04 +03:00
* to mmu_notifier_release(mm) ensures mmu notifier callbacks in
* __oom_reap_task_mm() will not block.
*
* This needs to be done before calling munlock_vma_pages_all(),
* which clears VM_LOCKED, otherwise the oom reaper cannot
* reliably test it.
*/
mm, oom: distinguish blockable mode for mmu notifiers There are several blockable mmu notifiers which might sleep in mmu_notifier_invalidate_range_start and that is a problem for the oom_reaper because it needs to guarantee a forward progress so it cannot depend on any sleepable locks. Currently we simply back off and mark an oom victim with blockable mmu notifiers as done after a short sleep. That can result in selecting a new oom victim prematurely because the previous one still hasn't torn its memory down yet. We can do much better though. Even if mmu notifiers use sleepable locks there is no reason to automatically assume those locks are held. Moreover majority of notifiers only care about a portion of the address space and there is absolutely zero reason to fail when we are unmapping an unrelated range. Many notifiers do really block and wait for HW which is harder to handle and we have to bail out though. This patch handles the low hanging fruit. __mmu_notifier_invalidate_range_start gets a blockable flag and callbacks are not allowed to sleep if the flag is set to false. This is achieved by using trylock instead of the sleepable lock for most callbacks and continue as long as we do not block down the call chain. I think we can improve that even further because there is a common pattern to do a range lookup first and then do something about that. The first part can be done without a sleeping lock in most cases AFAICS. The oom_reaper end then simply retries if there is at least one notifier which couldn't make any progress in !blockable mode. A retry loop is already implemented to wait for the mmap_sem and this is basically the same thing. The simplest way for driver developers to test this code path is to wrap userspace code which uses these notifiers into a memcg and set the hard limit to hit the oom. This can be done e.g. after the test faults in all the mmu notifier managed memory and set the hard limit to something really small. Then we are looking for a proper process tear down. [akpm@linux-foundation.org: coding style fixes] [akpm@linux-foundation.org: minor code simplification] Link: http://lkml.kernel.org/r/20180716115058.5559-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Christian König <christian.koenig@amd.com> # AMD notifiers Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx and umem_odp Reported-by: David Rientjes <rientjes@google.com> Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Mike Marciniszyn <mike.marciniszyn@intel.com> Cc: Dennis Dalessandro <dennis.dalessandro@intel.com> Cc: Sudeep Dutt <sudeep.dutt@intel.com> Cc: Ashutosh Dixit <ashutosh.dixit@intel.com> Cc: Dimitri Sivanich <sivanich@sgi.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:52:33 +03:00
(void)__oom_reap_task_mm(mm);
mm, oom: fix concurrent munlock and oom reaper unmap, v3 Since exit_mmap() is done without the protection of mm->mmap_sem, it is possible for the oom reaper to concurrently operate on an mm until MMF_OOM_SKIP is set. This allows munlock_vma_pages_all() to concurrently run while the oom reaper is operating on a vma. Since munlock_vma_pages_range() depends on clearing VM_LOCKED from vm_flags before actually doing the munlock to determine if any other vmas are locking the same memory, the check for VM_LOCKED in the oom reaper is racy. This is especially noticeable on architectures such as powerpc where clearing a huge pmd requires serialize_against_pte_lookup(). If the pmd is zapped by the oom reaper during follow_page_mask() after the check for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a kernel oops. Fix this by manually freeing all possible memory from the mm before doing the munlock and then setting MMF_OOM_SKIP. The oom reaper can not run on the mm anymore so the munlock is safe to do in exit_mmap(). It also matches the logic that the oom reaper currently uses for determining when to set MMF_OOM_SKIP itself, so there's no new risk of excessive oom killing. This issue fixes CVE-2018-1000200. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com Fixes: 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently") Signed-off-by: David Rientjes <rientjes@google.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-12 02:02:04 +03:00
set_bit(MMF_OOM_SKIP, &mm->flags);
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
mmap_write_lock(mm);
mmap_write_unlock(mm);
mm, oom: fix concurrent munlock and oom reaper unmap, v3 Since exit_mmap() is done without the protection of mm->mmap_sem, it is possible for the oom reaper to concurrently operate on an mm until MMF_OOM_SKIP is set. This allows munlock_vma_pages_all() to concurrently run while the oom reaper is operating on a vma. Since munlock_vma_pages_range() depends on clearing VM_LOCKED from vm_flags before actually doing the munlock to determine if any other vmas are locking the same memory, the check for VM_LOCKED in the oom reaper is racy. This is especially noticeable on architectures such as powerpc where clearing a huge pmd requires serialize_against_pte_lookup(). If the pmd is zapped by the oom reaper during follow_page_mask() after the check for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a kernel oops. Fix this by manually freeing all possible memory from the mm before doing the munlock and then setting MMF_OOM_SKIP. The oom reaper can not run on the mm anymore so the munlock is safe to do in exit_mmap(). It also matches the logic that the oom reaper currently uses for determining when to set MMF_OOM_SKIP itself, so there's no new risk of excessive oom killing. This issue fixes CVE-2018-1000200. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com Fixes: 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently") Signed-off-by: David Rientjes <rientjes@google.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-12 02:02:04 +03:00
}
mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:26:50 +04:00
if (mm->locked_vm) {
vma = mm->mmap;
while (vma) {
if (vma->vm_flags & VM_LOCKED)
munlock_vma_pages_all(vma);
vma = vma->vm_next;
}
}
mm: rearrange exit_mmap() to unlock before arch_exit_mmap Christophe Saout reported [in precursor to: http://marc.info/?l=linux-kernel&m=123209902707347&w=4]: > Note that I also some a different issue with CONFIG_UNEVICTABLE_LRU. > Seems like Xen tears down current->mm early on process termination, so > that __get_user_pages in exit_mmap causes nasty messages when the > process had any mlocked pages. (in fact, it somehow manages to get into > the swapping code and produces a null pointer dereference trying to get > a swap token) Jeremy explained: Yes. In the normal case under Xen, an in-use pagetable is "pinned", meaning that it is RO to the kernel, and all updates must go via hypercall (or writes are trapped and emulated, which is much the same thing). An unpinned pagetable is not currently in use by any process, and can be directly accessed as normal RW pages. As an optimisation at process exit time, we unpin the pagetable as early as possible (switching the process to init_mm), so that all the normal pagetable teardown can happen with direct memory accesses. This happens in exit_mmap() -> arch_exit_mmap(). The munlocking happens a few lines below. The obvious thing to do would be to move arch_exit_mmap() to below the munlock code, but I think we'd want to call it even if mm->mmap is NULL, just to be on the safe side. Thus, this patch: exit_mmap() needs to unlock any locked vmas before calling arch_exit_mmap, as the latter may switch the current mm to init_mm, which would cause the former to fail. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christophe Saout <christophe@saout.de> Cc: Keir Fraser <keir.fraser@eu.citrix.com> Cc: Christophe Saout <christophe@saout.de> Cc: Alex Williamson <alex.williamson@hp.com> Cc: <stable@kernel.org> [2.6.28.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-12 00:04:41 +03:00
arch_exit_mmap(mm);
mmap: handle mlocked pages during map, remap, unmap Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 07:26:50 +04:00
vma = mm->mmap;
mm: rearrange exit_mmap() to unlock before arch_exit_mmap Christophe Saout reported [in precursor to: http://marc.info/?l=linux-kernel&m=123209902707347&w=4]: > Note that I also some a different issue with CONFIG_UNEVICTABLE_LRU. > Seems like Xen tears down current->mm early on process termination, so > that __get_user_pages in exit_mmap causes nasty messages when the > process had any mlocked pages. (in fact, it somehow manages to get into > the swapping code and produces a null pointer dereference trying to get > a swap token) Jeremy explained: Yes. In the normal case under Xen, an in-use pagetable is "pinned", meaning that it is RO to the kernel, and all updates must go via hypercall (or writes are trapped and emulated, which is much the same thing). An unpinned pagetable is not currently in use by any process, and can be directly accessed as normal RW pages. As an optimisation at process exit time, we unpin the pagetable as early as possible (switching the process to init_mm), so that all the normal pagetable teardown can happen with direct memory accesses. This happens in exit_mmap() -> arch_exit_mmap(). The munlocking happens a few lines below. The obvious thing to do would be to move arch_exit_mmap() to below the munlock code, but I think we'd want to call it even if mm->mmap is NULL, just to be on the safe side. Thus, this patch: exit_mmap() needs to unlock any locked vmas before calling arch_exit_mmap, as the latter may switch the current mm to init_mm, which would cause the former to fail. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christophe Saout <christophe@saout.de> Cc: Keir Fraser <keir.fraser@eu.citrix.com> Cc: Christophe Saout <christophe@saout.de> Cc: Alex Williamson <alex.williamson@hp.com> Cc: <stable@kernel.org> [2.6.28.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-12 00:04:41 +03:00
if (!vma) /* Can happen if dup_mmap() received an OOM */
return;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
lru_add_drain();
flush_cache_mm(mm);
Fix TLB gather virtual address range invalidation corner cases Ben Tebulin reported: "Since v3.7.2 on two independent machines a very specific Git repository fails in 9/10 cases on git-fsck due to an SHA1/memory failures. This only occurs on a very specific repository and can be reproduced stably on two independent laptops. Git mailing list ran out of ideas and for me this looks like some very exotic kernel issue" and bisected the failure to the backport of commit 53a59fc67f97 ("mm: limit mmu_gather batching to fix soft lockups on !CONFIG_PREEMPT"). That commit itself is not actually buggy, but what it does is to make it much more likely to hit the partial TLB invalidation case, since it introduces a new case in tlb_next_batch() that previously only ever happened when running out of memory. The real bug is that the TLB gather virtual memory range setup is subtly buggered. It was introduced in commit 597e1c3580b7 ("mm/mmu_gather: enable tlb flush range in generic mmu_gather"), and the range handling was already fixed at least once in commit e6c495a96ce0 ("mm: fix the TLB range flushed when __tlb_remove_page() runs out of slots"), but that fix was not complete. The problem with the TLB gather virtual address range is that it isn't set up by the initial tlb_gather_mmu() initialization (which didn't get the TLB range information), but it is set up ad-hoc later by the functions that actually flush the TLB. And so any such case that forgot to update the TLB range entries would potentially miss TLB invalidates. Rather than try to figure out exactly which particular ad-hoc range setup was missing (I personally suspect it's the hugetlb case in zap_huge_pmd(), which didn't have the same logic as zap_pte_range() did), this patch just gets rid of the problem at the source: make the TLB range information available to tlb_gather_mmu(), and initialize it when initializing all the other tlb gather fields. This makes the patch larger, but conceptually much simpler. And the end result is much more understandable; even if you want to play games with partial ranges when invalidating the TLB contents in chunks, now the range information is always there, and anybody who doesn't want to bother with it won't introduce subtle bugs. Ben verified that this fixes his problem. Reported-bisected-and-tested-by: Ben Tebulin <tebulin@googlemail.com> Build-testing-by: Stephen Rothwell <sfr@canb.auug.org.au> Build-testing-by: Richard Weinberger <richard.weinberger@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-08-15 22:42:25 +04:00
tlb_gather_mmu(&tlb, mm, 0, -1);
mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting xacct_add_tsk() relies on do_exit()->update_hiwater_xxx() and uses mm->hiwater_xxx directly, this leads to 2 problems: - taskstats_user_cmd() can call fill_pid()->xacct_add_tsk() at any moment before the task exits, so we should check the current values of rss/vm anyway. - do_exit()->update_hiwater_xxx() calls are racy. An exiting thread can be preempted right before mm->hiwater_xxx = new_val, and another thread can use A_LOT of memory and exit in between. When the first thread resumes it can be the last thread in the thread group, in that case we report the wrong hiwater_xxx values which do not take A_LOT into account. Introduce get_mm_hiwater_rss() and get_mm_hiwater_vm() helpers and change xacct_add_tsk() to use them. The first helper will also be used by rusage->ru_maxrss accounting. Kill do_exit()->update_hiwater_xxx() calls. Unless we are going to decrease rss/vm there is no point to update mm->hiwater_xxx, and nobody can look at this mm_struct when exit_mmap() actually unmaps the memory. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hugh@veritas.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-07 01:40:29 +03:00
/* update_hiwater_rss(mm) here? but nobody should be looking */
[PATCH] freepgt: free_pgtables use vma list Recent woes with some arches needing their own pgd_addr_end macro; and 4-level clear_page_range regression since 2.6.10's clear_page_tables; and its long-standing well-known inefficiency in searching throughout the higher-level page tables for those few entries to clear and free: all can be blamed on ignoring the list of vmas when we free page tables. Replace exit_mmap's clear_page_range of the total user address space by free_pgtables operating on the mm's vma list; unmap_region use it in the same way, giving floor and ceiling beyond which it may not free tables. This brings lmbench fork/exec/sh numbers back to 2.6.10 (unless preempt is enabled, in which case latency fixes spoil unmap_vmas throughput). Beware: the do_mmap_pgoff driver failure case must now use unmap_region instead of zap_page_range, since a page table might have been allocated, and can only be freed while it is touched by some vma. Move free_pgtables from mmap.c to memory.c, where its lower levels are adapted from the clear_page_range levels. (Most of free_pgtables' old code was actually for a non-existent case, prev not properly set up, dating from before hch gave us split_vma.) Pass mmu_gather** in the public interfaces, since we might want to add latency lockdrops later; but no attempt to do so yet, going by vma should itself reduce latency. But what if is_hugepage_only_range? Those ia64 and ppc64 cases need careful examination: put that off until a later patch of the series. What of x86_64's 32bit vdso page __map_syscall32 maps outside any vma? And the range to sparc64's flush_tlb_pgtables? It's less clear to me now that we need to do more than is done here - every PMD_SIZE ever occupied will be flushed, do we really have to flush every PGDIR_SIZE ever partially occupied? A shame to complicate it unnecessarily. Special thanks to David Miller for time spent repairing my ceilings. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-20 00:29:15 +04:00
/* Use -1 here to ensure all VMAs in the mm are unmapped */
vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces The VM accounting makes no sense at this level, and half of the callers didn't ever actually use the end result. The only time we want to unaccount the memory is when we actually remove the vma, so do the accounting at that point instead. This simplifies the interfaces (no need to pass down that silly page counter to functions that really don't care), and also makes it much more obvious what is actually going on: we do vm_[un]acct_memory() when adding or removing the vma, not on random page walking. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-07 00:54:06 +04:00
unmap_vmas(&tlb, vma, 0, -1);
mm: allow arch code to control the user page table ceiling On architectures where a pgd entry may be shared between user and kernel (e.g. ARM+LPAE), freeing page tables needs a ceiling other than 0. This patch introduces a generic USER_PGTABLES_CEILING that arch code can override. It is the responsibility of the arch code setting the ceiling to ensure the complete freeing of the page tables (usually in pgd_free()). [catalin.marinas@arm.com: commit log; shift_arg_pages(), asm-generic/pgtables.h changes] Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: <stable@vger.kernel.org> [3.3+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:07:44 +04:00
free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING);
VM: don't bother with feeding upper limit to tlb_finish_mmu() in exit_mmap() no point, really - the only instance that cares about those arguments of tlb_finish_mmu() is itanic and there we explicitly check if that's called from exit_mmap() (i.e. that ->fullmm is set), in which case we ignore those arguments completely. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-05 23:03:47 +04:00
tlb_finish_mmu(&tlb, 0, -1);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
[PATCH] mm: unlink vma before pagetables In most places the descent from pgd to pud to pmd to pte holds mmap_sem (exclusively or not), which ensures that free_pgtables cannot be freeing page tables from any level at the same time. But truncation and reverse mapping descend without mmap_sem. No problem: just make sure that a vma is unlinked from its prio_tree (or nonlinear list) and from its anon_vma list, after zapping the vma, but before freeing its page tables. Then neither vmtruncate nor rmap can reach that vma whose page tables are now volatile (nor do they need to reach it, since all its page entries have been zapped by this stage). The i_mmap_lock and anon_vma->lock already serialize this correctly; but the locking hierarchy is such that we cannot take them while holding page_table_lock. Well, we're trying to push that down anyway. So in this patch, move anon_vma_unlink and unlink_file_vma into free_pgtables, at the same time as moving page_table_lock around calls to unmap_vmas. tlb_gather_mmu and tlb_finish_mmu then fall outside the page_table_lock, but we made them preempt_disable and preempt_enable earlier; and a long source audit of all the architectures has shown no problem with removing page_table_lock from them. free_pgtables doesn't need page_table_lock for itself, nor for what it calls; tlb->mm->nr_ptes is usually protected by page_table_lock, but partly by non-exclusive mmap_sem - here it's decremented with exclusive mmap_sem, or mm_users 0. update_hiwater_rss and vm_unacct_memory don't need page_table_lock either. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:16:29 +03:00
* Walk the list again, actually closing and freeing it,
* with preemption enabled, without holding any MM locks.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces The VM accounting makes no sense at this level, and half of the callers didn't ever actually use the end result. The only time we want to unaccount the memory is when we actually remove the vma, so do the accounting at that point instead. This simplifies the interfaces (no need to pass down that silly page counter to functions that really don't care), and also makes it much more obvious what is actually going on: we do vm_[un]acct_memory() when adding or removing the vma, not on random page walking. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-07 00:54:06 +04:00
while (vma) {
if (vma->vm_flags & VM_ACCOUNT)
nr_accounted += vma_pages(vma);
[PATCH] mm: unlink_file_vma, remove_vma Divide remove_vm_struct into two parts: first anon_vma_unlink plus unlink_file_vma, to unlink the vma from the list and tree by which rmap or vmtruncate might find it; then remove_vma to close, fput and free. The intention here is to do the anon_vma_unlink and unlink_file_vma earlier, in free_pgtables before freeing any page tables: so we can be sure that any page tables traversed by rmap and vmtruncate are stable (and other, ordinary cases are stabilized by holding mmap_sem). This will be crucial to traversing pgd,pud,pmd without page_table_lock. But testing the split-out patch showed that lifting the page_table_lock is symbiotically necessary to make this change - the lock ordering is wrong to move those unlinks into free_pgtables while it's under ptlock. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 04:15:57 +03:00
vma = remove_vma(vma);
mm/mmap.c: Add cond_resched() for exit_mmap() CPU stalls A large process running on a heavily loaded system can encounter the following RCU CPU stall warning: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 3-....: (20998 ticks this GP) idle=4ea/1/0x4000000000000002 softirq=556558/556558 fqs=5190 (t=21013 jiffies g=1005461 q=132576) NMI backtrace for cpu 3 CPU: 3 PID: 501900 Comm: aio-free-ring-w Kdump: loaded Not tainted 5.2.9-108_fbk12_rc3_3858_gb83b75af7909 #1 Hardware name: Wiwynn HoneyBadger/PantherPlus, BIOS HBM6.71 02/03/2016 Call Trace: <IRQ> dump_stack+0x46/0x60 nmi_cpu_backtrace.cold.3+0x13/0x50 ? lapic_can_unplug_cpu.cold.27+0x34/0x34 nmi_trigger_cpumask_backtrace+0xba/0xca rcu_dump_cpu_stacks+0x99/0xc7 rcu_sched_clock_irq.cold.87+0x1aa/0x397 ? tick_sched_do_timer+0x60/0x60 update_process_times+0x28/0x60 tick_sched_timer+0x37/0x70 __hrtimer_run_queues+0xfe/0x270 hrtimer_interrupt+0xf4/0x210 smp_apic_timer_interrupt+0x5e/0x120 apic_timer_interrupt+0xf/0x20 </IRQ> RIP: 0010:kmem_cache_free+0x223/0x300 Code: 88 00 00 00 0f 85 ca 00 00 00 41 8b 55 18 31 f6 f7 da 41 f6 45 0a 02 40 0f 94 c6 83 c6 05 9c 41 5e fa e8 a0 a7 01 00 41 56 9d <49> 8b 47 08 a8 03 0f 85 87 00 00 00 65 48 ff 08 e9 3d fe ff ff 65 RSP: 0018:ffffc9000e8e3da8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 RAX: 0000000000020000 RBX: ffff88861b9de960 RCX: 0000000000000030 RDX: fffffffffffe41e8 RSI: 000060777fe3a100 RDI: 000000000001be18 RBP: ffffea00186e7780 R08: ffffffffffffffff R09: ffffffffffffffff R10: ffff88861b9dea28 R11: ffff88887ffde000 R12: ffffffff81230a1f R13: ffff888854684dc0 R14: 0000000000000206 R15: ffff8888547dbc00 ? remove_vma+0x4f/0x60 remove_vma+0x4f/0x60 exit_mmap+0xd6/0x160 mmput+0x4a/0x110 do_exit+0x278/0xae0 ? syscall_trace_enter+0x1d3/0x2b0 ? handle_mm_fault+0xaa/0x1c0 do_group_exit+0x3a/0xa0 __x64_sys_exit_group+0x14/0x20 do_syscall_64+0x42/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 And on a PREEMPT=n kernel, the "while (vma)" loop in exit_mmap() can run for a very long time given a large process. This commit therefore adds a cond_resched() to this loop, providing RCU any needed quiescent states. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: <linux-mm@kvack.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-17 02:46:10 +03:00
cond_resched();
vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces The VM accounting makes no sense at this level, and half of the callers didn't ever actually use the end result. The only time we want to unaccount the memory is when we actually remove the vma, so do the accounting at that point instead. This simplifies the interfaces (no need to pass down that silly page counter to functions that really don't care), and also makes it much more obvious what is actually going on: we do vm_[un]acct_memory() when adding or removing the vma, not on random page walking. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-07 00:54:06 +04:00
}
vm_unacct_memory(nr_accounted);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
/* Insert vm structure into process list sorted by address
* and into the inode's i_mmap tree. If vm_file is non-NULL
mm: convert i_mmap_mutex to rwsem The i_mmap_mutex is a close cousin of the anon vma lock, both protecting similar data, one for file backed pages and the other for anon memory. To this end, this lock can also be a rwsem. In addition, there are some important opportunities to share the lock when there are no tree modifications. This conversion is straightforward. For now, all users take the write lock. [sfr@canb.auug.org.au: update fremap.c] Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:54:24 +03:00
* then i_mmap_rwsem is taken here.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
struct vm_area_struct *prev;
struct rb_node **rb_link, *rb_parent;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm/mmap.c:insert_vm_struct(): check for failure before setting values There's no point in initializing vma->vm_pgoff if the insertion attempt will be failing anyway. Run the checks before performing the initialization. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 01:04:08 +03:00
if (find_vma_links(mm, vma->vm_start, vma->vm_end,
&prev, &rb_link, &rb_parent))
return -ENOMEM;
if ((vma->vm_flags & VM_ACCOUNT) &&
security_vm_enough_memory_mm(mm, vma_pages(vma)))
return -ENOMEM;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* The vm_pgoff of a purely anonymous vma should be irrelevant
* until its first write fault, when page's anon_vma and index
* are set. But now set the vm_pgoff it will almost certainly
* end up with (unless mremap moves it elsewhere before that
* first wfault), so /proc/pid/maps tells a consistent story.
*
* By setting it to reflect the virtual start address of the
* vma, merges and splits can happen in a seamless way, just
* using the existing file pgoff checks and manipulations.
mm/mmap.c: replace do_brk with do_brk_flags in comment of insert_vm_struct() Replace do_brk with do_brk_flags in comment of insert_vm_struct(), since do_brk was removed in following commit. Fixes: bb177a732c4369 ("mm: do not bug_on on incorrect length in __mm_populate()") Signed-off-by: Liao Pingfang <liao.pingfang@zte.com.cn> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/1600650778-43230-1-git-send-email-wang.yi59@zte.com.cn Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-14 02:54:18 +03:00
* Similarly in do_mmap and in do_brk_flags.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
mmap: fix the usage of ->vm_pgoff in special_mapping paths Test-case: #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <assert.h> void *find_vdso_vaddr(void) { FILE *perl; char buf[32] = {}; perl = popen("perl -e 'open STDIN,qq|/proc/@{[getppid]}/maps|;" "/^(.*?)-.*vdso/ && print hex $1 while <>'", "r"); fread(buf, sizeof(buf), 1, perl); fclose(perl); return (void *)atol(buf); } #define PAGE_SIZE 4096 int main(void) { void *vdso = find_vdso_vaddr(); assert(vdso); // of course they should differ, and they do so far printf("vdso pages differ: %d\n", !!memcmp(vdso, vdso + PAGE_SIZE, PAGE_SIZE)); // split into 2 vma's assert(mprotect(vdso, PAGE_SIZE, PROT_READ) == 0); // force another fault on the next check assert(madvise(vdso, 2 * PAGE_SIZE, MADV_DONTNEED) == 0); // now they no longer differ, the 2nd vm_pgoff is wrong printf("vdso pages differ: %d\n", !!memcmp(vdso, vdso + PAGE_SIZE, PAGE_SIZE)); return 0; } Output: vdso pages differ: 1 vdso pages differ: 0 This is because split_vma() correctly updates ->vm_pgoff, but the logic in insert_vm_struct() and special_mapping_fault() is absolutely broken, so the fault at vdso + PAGE_SIZE return the 1st page. The same happens if you simply unmap the 1st page. special_mapping_fault() does: pgoff = vmf->pgoff - vma->vm_pgoff; and this is _only_ correct if vma->vm_start mmaps the first page from ->vm_private_data array. vdso or any other user of install_special_mapping() is not anonymous, it has the "backing storage" even if it is just the array of pages. So we actually need to make vm_pgoff work as an offset in this array. Note: this also allows to fix another problem: currently gdb can't access "[vvar]" memory because in this case special_mapping_fault() doesn't work. Now that we can use ->vm_pgoff we can implement ->access() and fix this. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 00:58:31 +03:00
if (vma_is_anonymous(vma)) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
BUG_ON(vma->anon_vma);
vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
}
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 13:26:42 +04:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
vma_link(mm, vma, prev, rb_link, rb_parent);
return 0;
}
/*
* Copy the vma structure to a new location in the same mm,
* prior to moving page table entries, to effect an mremap move.
*/
struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
mm: avoid taking rmap locks in move_ptes() During mremap(), the destination VMA is generally placed after the original vma in rmap traversal order: in move_vma(), we always have new_pgoff >= vma->vm_pgoff, and as a result new_vma->vm_pgoff >= vma->vm_pgoff unless vma_merge() merged the new vma with an adjacent one. When the destination VMA is placed after the original in rmap traversal order, we can avoid taking the rmap locks in move_ptes(). Essentially, this reintroduces the optimization that had been disabled in "mm anon rmap: remove anon_vma_moveto_tail". The difference is that we don't try to impose the rmap traversal order; instead we just rely on things being in the desired order in the common case and fall back to taking locks in the uncommon case. Also we skip the i_mmap_mutex in addition to the anon_vma lock: in both cases, the vmas are traversed in increasing vm_pgoff order with ties resolved in tree insertion order. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:50 +04:00
unsigned long addr, unsigned long len, pgoff_t pgoff,
bool *need_rmap_locks)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
{
struct vm_area_struct *vma = *vmap;
unsigned long vma_start = vma->vm_start;
struct mm_struct *mm = vma->vm_mm;
struct vm_area_struct *new_vma, *prev;
struct rb_node **rb_link, *rb_parent;
mremap: enforce rmap src/dst vma ordering in case of vma_merge() succeeding in copy_vma() migrate was doing an rmap_walk with speculative lock-less access on pagetables. That could lead it to not serializing properly against mremap PT locks. But a second problem remains in the order of vmas in the same_anon_vma list used by the rmap_walk. If vma_merge succeeds in copy_vma, the src vma could be placed after the dst vma in the same_anon_vma list. That could still lead to migrate missing some pte. This patch adds an anon_vma_moveto_tail() function to force the dst vma at the end of the list before mremap starts to solve the problem. If the mremap is very large and there are a lots of parents or childs sharing the anon_vma root lock, this should still scale better than taking the anon_vma root lock around every pte copy practically for the whole duration of mremap. Update: Hugh noticed special care is needed in the error path where move_page_tables goes in the reverse direction, a second anon_vma_moveto_tail() call is needed in the error path. This program exercises the anon_vma_moveto_tail: === int main() { static struct timeval oldstamp, newstamp; long diffsec; char *p, *p2, *p3, *p4; if (posix_memalign((void **)&p, 2*1024*1024, SIZE)) perror("memalign"), exit(1); if (posix_memalign((void **)&p2, 2*1024*1024, SIZE)) perror("memalign"), exit(1); if (posix_memalign((void **)&p3, 2*1024*1024, SIZE)) perror("memalign"), exit(1); memset(p, 0xff, SIZE); printf("%p\n", p); memset(p2, 0xff, SIZE); memset(p3, 0x77, 4096); if (memcmp(p, p2, SIZE)) printf("error\n"); p4 = mremap(p+SIZE/2, SIZE/2, SIZE/2, MREMAP_FIXED|MREMAP_MAYMOVE, p3); if (p4 != p3) perror("mremap"), exit(1); p4 = mremap(p4, SIZE/2, SIZE/2, MREMAP_FIXED|MREMAP_MAYMOVE, p+SIZE/2); if (p4 != p+SIZE/2) perror("mremap"), exit(1); if (memcmp(p, p2, SIZE)) printf("error\n"); printf("ok\n"); return 0; } === $ perf probe -a anon_vma_moveto_tail Add new event: probe:anon_vma_moveto_tail (on anon_vma_moveto_tail) You can now use it on all perf tools, such as: perf record -e probe:anon_vma_moveto_tail -aR sleep 1 $ perf record -e probe:anon_vma_moveto_tail -aR ./anon_vma_moveto_tail 0x7f2ca2800000 ok [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.043 MB perf.data (~1860 samples) ] $ perf report --stdio 100.00% anon_vma_moveto [kernel.kallsyms] [k] anon_vma_moveto_tail Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Nai Xia <nai.xia@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Pawel Sikora <pluto@agmk.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-11 03:08:05 +04:00
bool faulted_in_anon_vma = true;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
/*
* If anonymous vma has not yet been faulted, update new pgoff
* to match new location, to increase its chance of merging.
*/
mremap: fix the wrong !vma->vm_file check in copy_vma() Test-case: #define _GNU_SOURCE #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <assert.h> void *find_vdso_vaddr(void) { FILE *perl; char buf[32] = {}; perl = popen("perl -e 'open STDIN,qq|/proc/@{[getppid]}/maps|;" "/^(.*?)-.*vdso/ && print hex $1 while <>'", "r"); fread(buf, sizeof(buf), 1, perl); fclose(perl); return (void *)atol(buf); } #define PAGE_SIZE 4096 void *get_unmapped_area(void) { void *p = mmap(0, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1,0); assert(p != MAP_FAILED); munmap(p, PAGE_SIZE); return p; } char save[2][PAGE_SIZE]; int main(void) { void *vdso = find_vdso_vaddr(); void *page[2]; assert(vdso); memcpy(save, vdso, sizeof (save)); // force another fault on the next check assert(madvise(vdso, 2 * PAGE_SIZE, MADV_DONTNEED) == 0); page[0] = mremap(vdso, PAGE_SIZE, PAGE_SIZE, MREMAP_FIXED | MREMAP_MAYMOVE, get_unmapped_area()); page[1] = mremap(vdso + PAGE_SIZE, PAGE_SIZE, PAGE_SIZE, MREMAP_FIXED | MREMAP_MAYMOVE, get_unmapped_area()); assert(page[0] != MAP_FAILED && page[1] != MAP_FAILED); printf("match: %d %d\n", !memcmp(save[0], page[0], PAGE_SIZE), !memcmp(save[1], page[1], PAGE_SIZE)); return 0; } fails without this patch. Before the previous commit it gets the wrong page, now it segfaults (which is imho better). This is because copy_vma() wrongly assumes that if vma->vm_file == NULL is irrelevant until the first fault which will use do_anonymous_page(). This is obviously wrong for the special mapping. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 00:58:34 +03:00
if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
pgoff = addr >> PAGE_SHIFT;
mremap: enforce rmap src/dst vma ordering in case of vma_merge() succeeding in copy_vma() migrate was doing an rmap_walk with speculative lock-less access on pagetables. That could lead it to not serializing properly against mremap PT locks. But a second problem remains in the order of vmas in the same_anon_vma list used by the rmap_walk. If vma_merge succeeds in copy_vma, the src vma could be placed after the dst vma in the same_anon_vma list. That could still lead to migrate missing some pte. This patch adds an anon_vma_moveto_tail() function to force the dst vma at the end of the list before mremap starts to solve the problem. If the mremap is very large and there are a lots of parents or childs sharing the anon_vma root lock, this should still scale better than taking the anon_vma root lock around every pte copy practically for the whole duration of mremap. Update: Hugh noticed special care is needed in the error path where move_page_tables goes in the reverse direction, a second anon_vma_moveto_tail() call is needed in the error path. This program exercises the anon_vma_moveto_tail: === int main() { static struct timeval oldstamp, newstamp; long diffsec; char *p, *p2, *p3, *p4; if (posix_memalign((void **)&p, 2*1024*1024, SIZE)) perror("memalign"), exit(1); if (posix_memalign((void **)&p2, 2*1024*1024, SIZE)) perror("memalign"), exit(1); if (posix_memalign((void **)&p3, 2*1024*1024, SIZE)) perror("memalign"), exit(1); memset(p, 0xff, SIZE); printf("%p\n", p); memset(p2, 0xff, SIZE); memset(p3, 0x77, 4096); if (memcmp(p, p2, SIZE)) printf("error\n"); p4 = mremap(p+SIZE/2, SIZE/2, SIZE/2, MREMAP_FIXED|MREMAP_MAYMOVE, p3); if (p4 != p3) perror("mremap"), exit(1); p4 = mremap(p4, SIZE/2, SIZE/2, MREMAP_FIXED|MREMAP_MAYMOVE, p+SIZE/2); if (p4 != p+SIZE/2) perror("mremap"), exit(1); if (memcmp(p, p2, SIZE)) printf("error\n"); printf("ok\n"); return 0; } === $ perf probe -a anon_vma_moveto_tail Add new event: probe:anon_vma_moveto_tail (on anon_vma_moveto_tail) You can now use it on all perf tools, such as: perf record -e probe:anon_vma_moveto_tail -aR sleep 1 $ perf record -e probe:anon_vma_moveto_tail -aR ./anon_vma_moveto_tail 0x7f2ca2800000 ok [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.043 MB perf.data (~1860 samples) ] $ perf report --stdio 100.00% anon_vma_moveto [kernel.kallsyms] [k] anon_vma_moveto_tail Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Nai Xia <nai.xia@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Pawel Sikora <pluto@agmk.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-11 03:08:05 +04:00
faulted_in_anon_vma = false;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links() People get confused by find_vma_prepare(), because it doesn't care about what it returns in its output args, when its callers won't be interested. Clarify by passing in end-of-range address too, and returning failure if any existing vma overlaps the new range: instead of returning an ambiguous vma which most callers then must check. find_vma_links() is a clearer name. This does revert 2.6.27's dfe195fb79e88 ("mm: fix uninitialized variables for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of those releases too eager to shout about uninitialized variables: only copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences. [hughd@google.com: fix warning, remove BUG()] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Benny Halevy <bhalevy@tonian.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:29:07 +04:00
if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
return NULL; /* should never get here */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 01:46:24 +03:00
vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
vma->vm_userfaultfd_ctx);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
if (new_vma) {
/*
* Source vma may have been merged into new_vma
*/
mremap: enforce rmap src/dst vma ordering in case of vma_merge() succeeding in copy_vma() migrate was doing an rmap_walk with speculative lock-less access on pagetables. That could lead it to not serializing properly against mremap PT locks. But a second problem remains in the order of vmas in the same_anon_vma list used by the rmap_walk. If vma_merge succeeds in copy_vma, the src vma could be placed after the dst vma in the same_anon_vma list. That could still lead to migrate missing some pte. This patch adds an anon_vma_moveto_tail() function to force the dst vma at the end of the list before mremap starts to solve the problem. If the mremap is very large and there are a lots of parents or childs sharing the anon_vma root lock, this should still scale better than taking the anon_vma root lock around every pte copy practically for the whole duration of mremap. Update: Hugh noticed special care is needed in the error path where move_page_tables goes in the reverse direction, a second anon_vma_moveto_tail() call is needed in the error path. This program exercises the anon_vma_moveto_tail: === int main() { static struct timeval oldstamp, newstamp; long diffsec; char *p, *p2, *p3, *p4; if (posix_memalign((void **)&p, 2*1024*1024, SIZE)) perror("memalign"), exit(1); if (posix_memalign((void **)&p2, 2*1024*1024, SIZE)) perror("memalign"), exit(1); if (posix_memalign((void **)&p3, 2*1024*1024, SIZE)) perror("memalign"), exit(1); memset(p, 0xff, SIZE); printf("%p\n", p); memset(p2, 0xff, SIZE); memset(p3, 0x77, 4096); if (memcmp(p, p2, SIZE)) printf("error\n"); p4 = mremap(p+SIZE/2, SIZE/2, SIZE/2, MREMAP_FIXED|MREMAP_MAYMOVE, p3); if (p4 != p3) perror("mremap"), exit(1); p4 = mremap(p4, SIZE/2, SIZE/2, MREMAP_FIXED|MREMAP_MAYMOVE, p+SIZE/2); if (p4 != p+SIZE/2) perror("mremap"), exit(1); if (memcmp(p, p2, SIZE)) printf("error\n"); printf("ok\n"); return 0; } === $ perf probe -a anon_vma_moveto_tail Add new event: probe:anon_vma_moveto_tail (on anon_vma_moveto_tail) You can now use it on all perf tools, such as: perf record -e probe:anon_vma_moveto_tail -aR sleep 1 $ perf record -e probe:anon_vma_moveto_tail -aR ./anon_vma_moveto_tail 0x7f2ca2800000 ok [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.043 MB perf.data (~1860 samples) ] $ perf report --stdio 100.00% anon_vma_moveto [kernel.kallsyms] [k] anon_vma_moveto_tail Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Nai Xia <nai.xia@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Pawel Sikora <pluto@agmk.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-11 03:08:05 +04:00
if (unlikely(vma_start >= new_vma->vm_start &&
vma_start < new_vma->vm_end)) {
/*
* The only way we can get a vma_merge with
* self during an mremap is if the vma hasn't
* been faulted in yet and we were allowed to
* reset the dst vma->vm_pgoff to the
* destination address of the mremap to allow
* the merge to happen. mremap must change the
* vm_pgoff linearity between src and dst vmas
* (in turn preventing a vma_merge) to be
* safe. It is only safe to keep the vm_pgoff
* linear if there are no pages mapped yet.
*/
mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA Trivially convert a few VM_BUG_ON calls to VM_BUG_ON_VMA to extract more information when they trigger. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michel Lespinasse <walken@google.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 02:28:10 +04:00
VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma);
mm: avoid taking rmap locks in move_ptes() During mremap(), the destination VMA is generally placed after the original vma in rmap traversal order: in move_vma(), we always have new_pgoff >= vma->vm_pgoff, and as a result new_vma->vm_pgoff >= vma->vm_pgoff unless vma_merge() merged the new vma with an adjacent one. When the destination VMA is placed after the original in rmap traversal order, we can avoid taking the rmap locks in move_ptes(). Essentially, this reintroduces the optimization that had been disabled in "mm anon rmap: remove anon_vma_moveto_tail". The difference is that we don't try to impose the rmap traversal order; instead we just rely on things being in the desired order in the common case and fall back to taking locks in the uncommon case. Also we skip the i_mmap_mutex in addition to the anon_vma lock: in both cases, the vmas are traversed in increasing vm_pgoff order with ties resolved in tree insertion order. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:50 +04:00
*vmap = vma = new_vma;
mm anon rmap: remove anon_vma_moveto_tail mremap() had a clever optimization where move_ptes() did not take the anon_vma lock to avoid a race with anon rmap users such as page migration. Instead, the avc's were ordered in such a way that the origin vma was always visited by rmap before the destination. This ordering and the use of page table locks rmap usage safe. However, we want to replace the use of linked lists in anon rmap with an interval tree, and this will make it harder to impose such ordering as the interval tree will always be sorted by the avc->vma->vm_pgoff value. For now, let's replace the anon_vma_moveto_tail() ordering function with proper anon_vma locking in move_ptes(). Once we have the anon interval tree in place, we will re-introduce an optimization to avoid taking these locks in the most common cases. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:36 +04:00
}
mm: avoid taking rmap locks in move_ptes() During mremap(), the destination VMA is generally placed after the original vma in rmap traversal order: in move_vma(), we always have new_pgoff >= vma->vm_pgoff, and as a result new_vma->vm_pgoff >= vma->vm_pgoff unless vma_merge() merged the new vma with an adjacent one. When the destination VMA is placed after the original in rmap traversal order, we can avoid taking the rmap locks in move_ptes(). Essentially, this reintroduces the optimization that had been disabled in "mm anon rmap: remove anon_vma_moveto_tail". The difference is that we don't try to impose the rmap traversal order; instead we just rely on things being in the desired order in the common case and fall back to taking locks in the uncommon case. Also we skip the i_mmap_mutex in addition to the anon_vma lock: in both cases, the vmas are traversed in increasing vm_pgoff order with ties resolved in tree insertion order. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:50 +04:00
*need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
} else {
mm: use helper functions for allocating and freeing vm_area structs The vm_area_struct is one of the most fundamental memory management objects, but the management of it is entirely open-coded evertwhere, ranging from allocation and freeing (using kmem_cache_[z]alloc and kmem_cache_free) to initializing all the fields. We want to unify this in order to end up having some unified initialization of the vmas, and the first step to this is to at least have basic allocation functions. Right now those functions are literally just wrappers around the kmem_cache_*() calls. This is a purely mechanical conversion: # new vma: kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc() # copy old vma kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old) # free vma kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma) to the point where the old vma passed in to the vm_area_dup() function isn't even used yet (because I've left all the old manual initialization alone). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-21 23:48:51 +03:00
new_vma = vm_area_dup(vma);
mm/mmap.c: simplify the failure return working flow __split_vma() doesn't need out_err label, neither need initializing err. copy_vma() can return NULL directly when kmem_cache_alloc() fails. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 01:03:38 +03:00
if (!new_vma)
goto out;
new_vma->vm_start = addr;
new_vma->vm_end = addr + len;
new_vma->vm_pgoff = pgoff;
if (vma_dup_policy(vma, new_vma))
goto out_free_vma;
if (anon_vma_clone(new_vma, vma))
goto out_free_mempol;
if (new_vma->vm_file)
get_file(new_vma->vm_file);
if (new_vma->vm_ops && new_vma->vm_ops->open)
new_vma->vm_ops->open(new_vma);
vma_link(mm, new_vma, prev, rb_link, rb_parent);
*need_rmap_locks = false;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
return new_vma;
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
mm/mmap.c: simplify the failure return working flow __split_vma() doesn't need out_err label, neither need initializing err. copy_vma() can return NULL directly when kmem_cache_alloc() fails. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 01:03:38 +03:00
out_free_mempol:
mm: mempolicy: turn vma_set_policy() into vma_dup_policy() Simple cleanup. Every user of vma_set_policy() does the same work, this looks a bit annoying imho. And the new trivial helper which does mpol_dup() + vma_set_policy() to simplify the callers. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:20:14 +04:00
mpol_put(vma_policy(new_vma));
mm/mmap.c: simplify the failure return working flow __split_vma() doesn't need out_err label, neither need initializing err. copy_vma() can return NULL directly when kmem_cache_alloc() fails. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 01:03:38 +03:00
out_free_vma:
mm: use helper functions for allocating and freeing vm_area structs The vm_area_struct is one of the most fundamental memory management objects, but the management of it is entirely open-coded evertwhere, ranging from allocation and freeing (using kmem_cache_[z]alloc and kmem_cache_free) to initializing all the fields. We want to unify this in order to end up having some unified initialization of the vmas, and the first step to this is to at least have basic allocation functions. Right now those functions are literally just wrappers around the kmem_cache_*() calls. This is a purely mechanical conversion: # new vma: kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc() # copy old vma kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old) # free vma kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma) to the point where the old vma passed in to the vm_area_dup() function isn't even used yet (because I've left all the old manual initialization alone). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-21 23:48:51 +03:00
vm_area_free(new_vma);
mm/mmap.c: simplify the failure return working flow __split_vma() doesn't need out_err label, neither need initializing err. copy_vma() can return NULL directly when kmem_cache_alloc() fails. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 01:03:38 +03:00
out:
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
return NULL;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
}
[PATCH] RLIMIT_AS checking fix Address bug #4508: there's potential for wraparound in the various places where we perform RLIMIT_AS checking. (I'm a bit worried about acct_stack_growth(). Are we sure that vma->vm_mm is always equal to current->mm? If not, then we're comparing some other process's total_vm with the calling process's rlimits). Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 19:58:35 +04:00
/*
* Return true if the calling process may expand its vm space by the passed
* number of pages
*/
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages)
[PATCH] RLIMIT_AS checking fix Address bug #4508: there's potential for wraparound in the various places where we perform RLIMIT_AS checking. (I'm a bit worried about acct_stack_growth(). Are we sure that vma->vm_mm is always equal to current->mm? If not, then we're comparing some other process's total_vm with the calling process's rlimits). Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 19:58:35 +04:00
{
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT)
return false;
[PATCH] RLIMIT_AS checking fix Address bug #4508: there's potential for wraparound in the various places where we perform RLIMIT_AS checking. (I'm a bit worried about acct_stack_growth(). Are we sure that vma->vm_mm is always equal to current->mm? If not, then we're comparing some other process's total_vm with the calling process's rlimits). Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 19:58:35 +04:00
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 03:57:43 +03:00
if (is_data_mapping(flags) &&
mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) {
mm: enable RLIMIT_DATA by default with workaround for valgrind Since commit 84638335900f ("mm: rework virtual memory accounting") RLIMIT_DATA limits both brk() and private mmap() but this's disabled by default because of incompatibility with older versions of valgrind. Valgrind always set limit to zero and fails if RLIMIT_DATA is enabled. Fortunately it changes only rlim_cur and keeps rlim_max for reverting limit back when needed. This patch checks current usage also against rlim_max if rlim_cur is zero. This is safe because task anyway can increase rlim_cur up to rlim_max. Size of brk is still checked against rlim_cur, so this part is completely compatible - zero rlim_cur forbids brk() but allows private mmap(). Link: http://lkml.kernel.org/r/56A28613.5070104@de.ibm.com Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-21 02:57:45 +03:00
/* Workaround for Valgrind */
if (rlimit(RLIMIT_DATA) == 0 &&
mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT)
return true;
mm: always print RLIMIT_DATA warning The documentation for ignore_rlimit_data says that it will print a warning at first misuse. Yet it doesn't seem to do that. Fix the code to print the warning even when we allow the process to continue. Link: http://lkml.kernel.org/r/1517935505-9321-1-git-send-email-dwmw@amazon.co.uk Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Acked-by: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-06 02:22:05 +03:00
pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n",
current->comm, current->pid,
(mm->data_vm + npages) << PAGE_SHIFT,
rlimit(RLIMIT_DATA),
ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data");
if (!ignore_rlimit_data)
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 03:57:43 +03:00
return false;
}
[PATCH] RLIMIT_AS checking fix Address bug #4508: there's potential for wraparound in the various places where we perform RLIMIT_AS checking. (I'm a bit worried about acct_stack_growth(). Are we sure that vma->vm_mm is always equal to current->mm? If not, then we're comparing some other process's total_vm with the calling process's rlimits). Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 19:58:35 +04:00
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
return true;
}
void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages)
{
mm->total_vm += npages;
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 03:57:43 +03:00
if (is_exec_mapping(flags))
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
mm->exec_vm += npages;
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 03:57:43 +03:00
else if (is_stack_mapping(flags))
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
mm->stack_vm += npages;
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 03:57:43 +03:00
else if (is_data_mapping(flags))
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
mm->data_vm += npages;
[PATCH] RLIMIT_AS checking fix Address bug #4508: there's potential for wraparound in the various places where we perform RLIMIT_AS checking. (I'm a bit worried about acct_stack_growth(). Are we sure that vma->vm_mm is always equal to current->mm? If not, then we're comparing some other process's total_vm with the calling process's rlimits). Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 19:58:35 +04:00
}
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
mm: change return type to vm_fault_t Use new return type vm_fault_t for fault handler in struct vm_operations_struct. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. See commit 1c8f422059ae ("mm: change return type to vm_fault_t") Link: http://lkml.kernel.org/r/20180512063745.GA26866@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Joe Perches <joe@perches.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08 03:08:04 +03:00
static vm_fault_t special_mapping_fault(struct vm_fault *vmf);
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
/*
* Having a close hook prevents vma merging regardless of flags.
*/
static void special_mapping_close(struct vm_area_struct *vma)
{
}
static const char *special_mapping_name(struct vm_area_struct *vma)
{
return ((struct vm_special_mapping *)vma->vm_private_data)->name;
}
x86/vdso: Add mremap hook to vm_special_mapping Add possibility for 32-bit user-space applications to move the vDSO mapping. Previously, when a user-space app called mremap() for the vDSO address, in the syscall return path it would land on the previous address of the vDSOpage, resulting in segmentation violation. Now it lands fine and returns to userspace with a remapped vDSO. This will also fix the context.vdso pointer for 64-bit, which does not affect the user of vDSO after mremap() currently, but this may change in the future. As suggested by Andy, return -EINVAL for mremap() that would split the vDSO image: that operation cannot possibly result in a working system so reject it. Renamed and moved the text_mapping structure declaration inside map_vdso(), as it used only there and now it complements the vvar_mapping variable. There is still a problem for remapping the vDSO in glibc applications: the linker relocates addresses for syscalls on the vDSO page, so you need to relink with the new addresses. Without that the next syscall through glibc may fail: Program received signal SIGSEGV, Segmentation fault. #0 0xf7fd9b80 in __kernel_vsyscall () #1 0xf7ec8238 in _exit () from /usr/lib32/libc.so.6 Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: 0x7f454c46@gmail.com Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160628113539.13606-2-dsafonov@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-28 14:35:38 +03:00
static int special_mapping_mremap(struct vm_area_struct *new_vma)
{
struct vm_special_mapping *sm = new_vma->vm_private_data;
ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO CRIU restores application mappings on the same place where they were before Checkpoint. That means, that we need to move vDSO and sigpage during restore on exactly the same place where they were before C/R. Make mremap() code update mm->context.{sigpage,vdso} pointers during VMA move. Sigpage is used for landing after handling a signal - if the pointer is not updated during moving, the application might crash on any signal after mremap(). vDSO pointer on ARM32 is used only for setting auxv at this moment, update it during mremap() in case of future usage. Without those updates, current work of CRIU on ARM32 is not reliable. Historically, we error Checkpointing if we find vDSO page on ARM32 and suggest user to disable CONFIG_VDSO. But that's not correct - it goes from x86 where signal processing is ended in vDSO blob. For arm32 it's sigpage, which is not disabled with `CONFIG_VDSO=n'. Looks like C/R was working by luck - because userspace on ARM32 at this moment always sets SA_RESTORER. Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Acked-by: Andy Lutomirski <luto@amacapital.net> Cc: linux-arm-kernel@lists.infradead.org Cc: Will Deacon <will.deacon@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Christopher Covington <cov@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-06-19 19:32:42 +03:00
if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
return -EFAULT;
x86/vdso: Add mremap hook to vm_special_mapping Add possibility for 32-bit user-space applications to move the vDSO mapping. Previously, when a user-space app called mremap() for the vDSO address, in the syscall return path it would land on the previous address of the vDSOpage, resulting in segmentation violation. Now it lands fine and returns to userspace with a remapped vDSO. This will also fix the context.vdso pointer for 64-bit, which does not affect the user of vDSO after mremap() currently, but this may change in the future. As suggested by Andy, return -EINVAL for mremap() that would split the vDSO image: that operation cannot possibly result in a working system so reject it. Renamed and moved the text_mapping structure declaration inside map_vdso(), as it used only there and now it complements the vvar_mapping variable. There is still a problem for remapping the vDSO in glibc applications: the linker relocates addresses for syscalls on the vDSO page, so you need to relink with the new addresses. Without that the next syscall through glibc may fail: Program received signal SIGSEGV, Segmentation fault. #0 0xf7fd9b80 in __kernel_vsyscall () #1 0xf7ec8238 in _exit () from /usr/lib32/libc.so.6 Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: 0x7f454c46@gmail.com Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160628113539.13606-2-dsafonov@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-28 14:35:38 +03:00
if (sm->mremap)
return sm->mremap(sm, new_vma);
ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO CRIU restores application mappings on the same place where they were before Checkpoint. That means, that we need to move vDSO and sigpage during restore on exactly the same place where they were before C/R. Make mremap() code update mm->context.{sigpage,vdso} pointers during VMA move. Sigpage is used for landing after handling a signal - if the pointer is not updated during moving, the application might crash on any signal after mremap(). vDSO pointer on ARM32 is used only for setting auxv at this moment, update it during mremap() in case of future usage. Without those updates, current work of CRIU on ARM32 is not reliable. Historically, we error Checkpointing if we find vDSO page on ARM32 and suggest user to disable CONFIG_VDSO. But that's not correct - it goes from x86 where signal processing is ended in vDSO blob. For arm32 it's sigpage, which is not disabled with `CONFIG_VDSO=n'. Looks like C/R was working by luck - because userspace on ARM32 at this moment always sets SA_RESTORER. Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Acked-by: Andy Lutomirski <luto@amacapital.net> Cc: linux-arm-kernel@lists.infradead.org Cc: Will Deacon <will.deacon@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Christopher Covington <cov@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-06-19 19:32:42 +03:00
x86/vdso: Add mremap hook to vm_special_mapping Add possibility for 32-bit user-space applications to move the vDSO mapping. Previously, when a user-space app called mremap() for the vDSO address, in the syscall return path it would land on the previous address of the vDSOpage, resulting in segmentation violation. Now it lands fine and returns to userspace with a remapped vDSO. This will also fix the context.vdso pointer for 64-bit, which does not affect the user of vDSO after mremap() currently, but this may change in the future. As suggested by Andy, return -EINVAL for mremap() that would split the vDSO image: that operation cannot possibly result in a working system so reject it. Renamed and moved the text_mapping structure declaration inside map_vdso(), as it used only there and now it complements the vvar_mapping variable. There is still a problem for remapping the vDSO in glibc applications: the linker relocates addresses for syscalls on the vDSO page, so you need to relink with the new addresses. Without that the next syscall through glibc may fail: Program received signal SIGSEGV, Segmentation fault. #0 0xf7fd9b80 in __kernel_vsyscall () #1 0xf7ec8238 in _exit () from /usr/lib32/libc.so.6 Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: 0x7f454c46@gmail.com Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160628113539.13606-2-dsafonov@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-28 14:35:38 +03:00
return 0;
}
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
static const struct vm_operations_struct special_mapping_vmops = {
.close = special_mapping_close,
.fault = special_mapping_fault,
x86/vdso: Add mremap hook to vm_special_mapping Add possibility for 32-bit user-space applications to move the vDSO mapping. Previously, when a user-space app called mremap() for the vDSO address, in the syscall return path it would land on the previous address of the vDSOpage, resulting in segmentation violation. Now it lands fine and returns to userspace with a remapped vDSO. This will also fix the context.vdso pointer for 64-bit, which does not affect the user of vDSO after mremap() currently, but this may change in the future. As suggested by Andy, return -EINVAL for mremap() that would split the vDSO image: that operation cannot possibly result in a working system so reject it. Renamed and moved the text_mapping structure declaration inside map_vdso(), as it used only there and now it complements the vvar_mapping variable. There is still a problem for remapping the vDSO in glibc applications: the linker relocates addresses for syscalls on the vDSO page, so you need to relink with the new addresses. Without that the next syscall through glibc may fail: Program received signal SIGSEGV, Segmentation fault. #0 0xf7fd9b80 in __kernel_vsyscall () #1 0xf7ec8238 in _exit () from /usr/lib32/libc.so.6 Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: 0x7f454c46@gmail.com Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160628113539.13606-2-dsafonov@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-28 14:35:38 +03:00
.mremap = special_mapping_mremap,
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
.name = special_mapping_name,
x86/vdso: Handle faults on timens page If a task belongs to a time namespace then the VVAR page which contains the system wide VDSO data is replaced with a namespace specific page which has the same layout as the VVAR page. Co-developed-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191112012724.250792-25-dima@arista.com
2019-11-12 04:27:13 +03:00
/* vDSO code relies that VVAR can't be accessed remotely */
.access = NULL,
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
};
static const struct vm_operations_struct legacy_special_mapping_vmops = {
.close = special_mapping_close,
.fault = special_mapping_fault,
};
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
mm: change return type to vm_fault_t Use new return type vm_fault_t for fault handler in struct vm_operations_struct. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. See commit 1c8f422059ae ("mm: change return type to vm_fault_t") Link: http://lkml.kernel.org/r/20180512063745.GA26866@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Joe Perches <joe@perches.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08 03:08:04 +03:00
static vm_fault_t special_mapping_fault(struct vm_fault *vmf)
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
{
mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf ->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to take a vma and vmf parameter when the vma already resides in vmf. Remove the vma parameter to simplify things. [arnd@arndb.de: fix ARM build] Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:56:41 +03:00
struct vm_area_struct *vma = vmf->vma;
mm: special mapping nopage Convert special mapping install from nopage to fault. Because the "vm_file" is NULL for the special mapping, the generic VM code has messed up "vm_pgoff" thinking that it's an anonymous mapping and the offset does't matter. For that reason, we need to undo the vm_pgoff offset that got added into vmf->pgoff. [ We _really_ should clean that up - either by making this whole special mapping code just use a real file entry rather than that ugly array of "struct page" pointers, or by just making the VM code realize that even if vm_file is NULL it may not be a regular anonymous mmap. - Linus ] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-09 03:15:19 +03:00
pgoff_t pgoff;
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
struct page **pages;
mm: Add a vm_special_mapping.fault() method Requiring special mappings to give a list of struct pages is inflexible: it prevents sane use of IO memory in a special mapping, it's inefficient (it requires arch code to initialize a list of struct pages, and it requires the mm core to walk the entire list just to figure out how long it is), and it prevents arch code from doing anything fancy when a special mapping fault occurs. Add a .fault method as an alternative to filling in a .pages array. Looks-OK-to: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a26d1677c0bc7e774c33f469451a78ca31e9e6af.1451446564.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-12-30 07:12:19 +03:00
if (vma->vm_ops == &legacy_special_mapping_vmops) {
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
pages = vma->vm_private_data;
mm: Add a vm_special_mapping.fault() method Requiring special mappings to give a list of struct pages is inflexible: it prevents sane use of IO memory in a special mapping, it's inefficient (it requires arch code to initialize a list of struct pages, and it requires the mm core to walk the entire list just to figure out how long it is), and it prevents arch code from doing anything fancy when a special mapping fault occurs. Add a .fault method as an alternative to filling in a .pages array. Looks-OK-to: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a26d1677c0bc7e774c33f469451a78ca31e9e6af.1451446564.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-12-30 07:12:19 +03:00
} else {
struct vm_special_mapping *sm = vma->vm_private_data;
if (sm->fault)
mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf ->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to take a vma and vmf parameter when the vma already resides in vmf. Remove the vma parameter to simplify things. [arnd@arndb.de: fix ARM build] Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:56:41 +03:00
return sm->fault(sm, vmf->vma, vmf);
mm: Add a vm_special_mapping.fault() method Requiring special mappings to give a list of struct pages is inflexible: it prevents sane use of IO memory in a special mapping, it's inefficient (it requires arch code to initialize a list of struct pages, and it requires the mm core to walk the entire list just to figure out how long it is), and it prevents arch code from doing anything fancy when a special mapping fault occurs. Add a .fault method as an alternative to filling in a .pages array. Looks-OK-to: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a26d1677c0bc7e774c33f469451a78ca31e9e6af.1451446564.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-12-30 07:12:19 +03:00
pages = sm->pages;
}
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
mmap: fix the usage of ->vm_pgoff in special_mapping paths Test-case: #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <assert.h> void *find_vdso_vaddr(void) { FILE *perl; char buf[32] = {}; perl = popen("perl -e 'open STDIN,qq|/proc/@{[getppid]}/maps|;" "/^(.*?)-.*vdso/ && print hex $1 while <>'", "r"); fread(buf, sizeof(buf), 1, perl); fclose(perl); return (void *)atol(buf); } #define PAGE_SIZE 4096 int main(void) { void *vdso = find_vdso_vaddr(); assert(vdso); // of course they should differ, and they do so far printf("vdso pages differ: %d\n", !!memcmp(vdso, vdso + PAGE_SIZE, PAGE_SIZE)); // split into 2 vma's assert(mprotect(vdso, PAGE_SIZE, PROT_READ) == 0); // force another fault on the next check assert(madvise(vdso, 2 * PAGE_SIZE, MADV_DONTNEED) == 0); // now they no longer differ, the 2nd vm_pgoff is wrong printf("vdso pages differ: %d\n", !!memcmp(vdso, vdso + PAGE_SIZE, PAGE_SIZE)); return 0; } Output: vdso pages differ: 1 vdso pages differ: 0 This is because split_vma() correctly updates ->vm_pgoff, but the logic in insert_vm_struct() and special_mapping_fault() is absolutely broken, so the fault at vdso + PAGE_SIZE return the 1st page. The same happens if you simply unmap the 1st page. special_mapping_fault() does: pgoff = vmf->pgoff - vma->vm_pgoff; and this is _only_ correct if vma->vm_start mmaps the first page from ->vm_private_data array. vdso or any other user of install_special_mapping() is not anonymous, it has the "backing storage" even if it is just the array of pages. So we actually need to make vm_pgoff work as an offset in this array. Note: this also allows to fix another problem: currently gdb can't access "[vvar]" memory because in this case special_mapping_fault() doesn't work. Now that we can use ->vm_pgoff we can implement ->access() and fix this. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09 00:58:31 +03:00
for (pgoff = vmf->pgoff; pgoff && *pages; ++pages)
mm: special mapping nopage Convert special mapping install from nopage to fault. Because the "vm_file" is NULL for the special mapping, the generic VM code has messed up "vm_pgoff" thinking that it's an anonymous mapping and the offset does't matter. For that reason, we need to undo the vm_pgoff offset that got added into vmf->pgoff. [ We _really_ should clean that up - either by making this whole special mapping code just use a real file entry rather than that ugly array of "struct page" pointers, or by just making the VM code realize that even if vm_file is NULL it may not be a regular anonymous mmap. - Linus ] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-09 03:15:19 +03:00
pgoff--;
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
if (*pages) {
struct page *page = *pages;
get_page(page);
mm: special mapping nopage Convert special mapping install from nopage to fault. Because the "vm_file" is NULL for the special mapping, the generic VM code has messed up "vm_pgoff" thinking that it's an anonymous mapping and the offset does't matter. For that reason, we need to undo the vm_pgoff offset that got added into vmf->pgoff. [ We _really_ should clean that up - either by making this whole special mapping code just use a real file entry rather than that ugly array of "struct page" pointers, or by just making the VM code realize that even if vm_file is NULL it may not be a regular anonymous mmap. - Linus ] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-09 03:15:19 +03:00
vmf->page = page;
return 0;
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
}
mm: special mapping nopage Convert special mapping install from nopage to fault. Because the "vm_file" is NULL for the special mapping, the generic VM code has messed up "vm_pgoff" thinking that it's an anonymous mapping and the offset does't matter. For that reason, we need to undo the vm_pgoff offset that got added into vmf->pgoff. [ We _really_ should clean that up - either by making this whole special mapping code just use a real file entry rather than that ugly array of "struct page" pointers, or by just making the VM code realize that even if vm_file is NULL it may not be a regular anonymous mmap. - Linus ] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-09 03:15:19 +03:00
return VM_FAULT_SIGBUS;
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
}
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
static struct vm_area_struct *__install_special_mapping(
struct mm_struct *mm,
unsigned long addr, unsigned long len,
mm/mmap.c: change __install_special_mapping() args order Make __install_special_mapping() args order match the caller, so the caller can pass their register args directly to callee with no touch. For most of architectures, args (at least the first 5th args) are in registers, so this change will have effect on most of architectures. For -O2, __install_special_mapping() may be inlined under most of architectures, but for -Os, it should not. So this change can get a little better performance for -Os, at least. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:41 +03:00
unsigned long vm_flags, void *priv,
const struct vm_operations_struct *ops)
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
{
install_special_mapping skips security_file_mmap check. The install_special_mapping routine (used, for example, to setup the vdso) skips the security check before insert_vm_struct, allowing a local attacker to bypass the mmap_min_addr security restriction by limiting the available pages for special mappings. bprm_mm_init() also skips the check, and although I don't think this can be used to bypass any restrictions, I don't see any reason not to have the security check. $ uname -m x86_64 $ cat /proc/sys/vm/mmap_min_addr 65536 $ cat install_special_mapping.s section .bss resb BSS_SIZE section .text global _start _start: mov eax, __NR_pause int 0x80 $ nasm -D__NR_pause=29 -DBSS_SIZE=0xfffed000 -f elf -o install_special_mapping.o install_special_mapping.s $ ld -m elf_i386 -Ttext=0x10000 -Tbss=0x11000 -o install_special_mapping install_special_mapping.o $ ./install_special_mapping & [1] 14303 $ cat /proc/14303/maps 0000f000-00010000 r-xp 00000000 00:00 0 [vdso] 00010000-00011000 r-xp 00001000 00:19 2453665 /home/taviso/install_special_mapping 00011000-ffffe000 rwxp 00000000 00:00 0 [stack] It's worth noting that Red Hat are shipping with mmap_min_addr set to 4096. Signed-off-by: Tavis Ormandy <taviso@google.com> Acked-by: Kees Cook <kees@ubuntu.com> Acked-by: Robert Swiecki <swiecki@google.com> [ Changed to not drop the error code - akpm ] Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-09 17:29:42 +03:00
int ret;
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
struct vm_area_struct *vma;
mm: make vm_area_alloc() initialize core fields Like vm_area_dup(), it initializes the anon_vma_chain head, and the basic mm pointer. The rest of the fields end up being different for different users, although the plan is to also initialize the 'vm_ops' field to a dummy entry. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-22 01:24:03 +03:00
vma = vm_area_alloc(mm);
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
if (unlikely(vma == NULL))
mm: Add new func _install_special_mapping() to mmap.c The _install_special_mapping() is the new base function for install_special_mapping(). This function will return a pointer of the created VMA or a error code in an ERR_PTR() This new function will be needed by the for the vdso 32 bit support to map the additonal vvar and hpet pages into the 32 bit address space. This will be done with io_remap_pfn_range() and remap_pfn_range, which requieres a vm_area_struct. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-3-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-03-18 02:22:02 +04:00
return ERR_PTR(-ENOMEM);
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
vma->vm_start = addr;
vma->vm_end = addr + len;
mm: track vma changes with VM_SOFTDIRTY bit Pavel reported that in case if vma area get unmapped and then mapped (or expanded) in-place, the soft dirty tracker won't be able to recognize this situation since it works on pte level and ptes are get zapped on unmap, loosing soft dirty bit of course. So to resolve this situation we need to track actions on vma level, there VM_SOFTDIRTY flag comes in. When new vma area created (or old expanded) we set this bit, and keep it here until application calls for clearing soft dirty bit. Thus when user space application track memory changes now it can detect if vma area is renewed. Reported-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Matt Mackall <mpm@selenic.com> Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-12 01:22:24 +04:00
vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY;
setup vma->vm_page_prot by vm_get_page_prot() This patch uses vm_get_page_prot() to setup vma->vm_page_prot. Though inside vm_get_page_prot() the protection flags is AND with (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED), it does not hurt correct code. Signed-off-by: Coly Li <coyli@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 10:39:15 +04:00
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
vma->vm_ops = ops;
vma->vm_private_data = priv;
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
install_special_mapping skips security_file_mmap check. The install_special_mapping routine (used, for example, to setup the vdso) skips the security check before insert_vm_struct, allowing a local attacker to bypass the mmap_min_addr security restriction by limiting the available pages for special mappings. bprm_mm_init() also skips the check, and although I don't think this can be used to bypass any restrictions, I don't see any reason not to have the security check. $ uname -m x86_64 $ cat /proc/sys/vm/mmap_min_addr 65536 $ cat install_special_mapping.s section .bss resb BSS_SIZE section .text global _start _start: mov eax, __NR_pause int 0x80 $ nasm -D__NR_pause=29 -DBSS_SIZE=0xfffed000 -f elf -o install_special_mapping.o install_special_mapping.s $ ld -m elf_i386 -Ttext=0x10000 -Tbss=0x11000 -o install_special_mapping install_special_mapping.o $ ./install_special_mapping & [1] 14303 $ cat /proc/14303/maps 0000f000-00010000 r-xp 00000000 00:00 0 [vdso] 00010000-00011000 r-xp 00001000 00:19 2453665 /home/taviso/install_special_mapping 00011000-ffffe000 rwxp 00000000 00:00 0 [stack] It's worth noting that Red Hat are shipping with mmap_min_addr set to 4096. Signed-off-by: Tavis Ormandy <taviso@google.com> Acked-by: Kees Cook <kees@ubuntu.com> Acked-by: Robert Swiecki <swiecki@google.com> [ Changed to not drop the error code - akpm ] Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-09 17:29:42 +03:00
ret = insert_vm_struct(mm, vma);
if (ret)
goto out;
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
mm: rework virtual memory accounting When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which testing the RLIMIT_DATA value to figure out if we're allowed to assign new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been commited that RLIMIT_DATA in a form it's implemented now doesn't do anything useful because most of user-space libraries use mmap() syscall for dynamic memory allocations. Linus suggested to convert RLIMIT_DATA rlimit into something suitable for anonymous memory accounting. But in this patch we go further, and the changes are bundled together as: * keep vma counting if CONFIG_PROC_FS=n, will be used for limits * replace mm->shared_vm with better defined mm->data_vm * account anonymous executable areas as executable * account file-backed growsdown/up areas as stack * drop struct file* argument from vm_stat_account * enforce RLIMIT_DATA for size of data areas This way code looks cleaner: now code/stack/data classification depends only on vm_flags state: VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc) VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk) VM_WRITE & ~VM_SHARED & !stack -> data (VmData) The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called "shared", but that might be strange beast like readonly-private or VM_IO area. - RLIMIT_AS limits whole address space "VmSize" - RLIMIT_STACK limits stack "VmStk" (but each vma individually) - RLIMIT_DATA now limits "VmData" Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Kees Cook <keescook@google.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 02:22:07 +03:00
vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT);
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
perf: Do the big rename: Performance Counters -> Performance Events Bye-bye Performance Counters, welcome Performance Events! In the past few months the perfcounters subsystem has grown out its initial role of counting hardware events, and has become (and is becoming) a much broader generic event enumeration, reporting, logging, monitoring, analysis facility. Naming its core object 'perf_counter' and naming the subsystem 'perfcounters' has become more and more of a misnomer. With pending code like hw-breakpoints support the 'counter' name is less and less appropriate. All in one, we've decided to rename the subsystem to 'performance events' and to propagate this rename through all fields, variables and API names. (in an ABI compatible fashion) The word 'event' is also a bit shorter than 'counter' - which makes it slightly more convenient to write/handle as well. Thanks goes to Stephane Eranian who first observed this misnomer and suggested a rename. User-space tooling and ABI compatibility is not affected - this patch should be function-invariant. (Also, defconfigs were not touched to keep the size down.) This patch has been generated via the following script: FILES=$(find * -type f | grep -vE 'oprofile|[^K]config') sed -i \ -e 's/PERF_EVENT_/PERF_RECORD_/g' \ -e 's/PERF_COUNTER/PERF_EVENT/g' \ -e 's/perf_counter/perf_event/g' \ -e 's/nb_counters/nb_events/g' \ -e 's/swcounter/swevent/g' \ -e 's/tpcounter_event/tp_event/g' \ $FILES for N in $(find . -name perf_counter.[ch]); do M=$(echo $N | sed 's/perf_counter/perf_event/g') mv $N $M done FILES=$(find . -name perf_event.*) sed -i \ -e 's/COUNTER_MASK/REG_MASK/g' \ -e 's/COUNTER/EVENT/g' \ -e 's/\<event\>/event_id/g' \ -e 's/counter/event/g' \ -e 's/Counter/Event/g' \ $FILES ... to keep it as correct as possible. This script can also be used by anyone who has pending perfcounters patches - it converts a Linux kernel tree over to the new naming. We tried to time this change to the point in time where the amount of pending patches is the smallest: the end of the merge window. Namespace clashes were fixed up in a preparatory patch - and some stylistic fallout will be fixed up in a subsequent patch. ( NOTE: 'counters' are still the proper terminology when we deal with hardware registers - and these sed scripts are a bit over-eager in renaming them. I've undone some of that, but in case there's something left where 'counter' would be better than 'event' we can undo that on an individual basis instead of touching an otherwise nicely automated patch. ) Suggested-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-21 14:02:48 +04:00
perf_event_mmap(vma);
perf_counter: Generate mmap events for install_special_mapping() In order to track the vdso also generate mmap events for install_special_mapping(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-05 16:04:55 +04:00
mm: Add new func _install_special_mapping() to mmap.c The _install_special_mapping() is the new base function for install_special_mapping(). This function will return a pointer of the created VMA or a error code in an ERR_PTR() This new function will be needed by the for the vdso 32 bit support to map the additonal vvar and hpet pages into the 32 bit address space. This will be done with io_remap_pfn_range() and remap_pfn_range, which requieres a vm_area_struct. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-3-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-03-18 02:22:02 +04:00
return vma;
install_special_mapping skips security_file_mmap check. The install_special_mapping routine (used, for example, to setup the vdso) skips the security check before insert_vm_struct, allowing a local attacker to bypass the mmap_min_addr security restriction by limiting the available pages for special mappings. bprm_mm_init() also skips the check, and although I don't think this can be used to bypass any restrictions, I don't see any reason not to have the security check. $ uname -m x86_64 $ cat /proc/sys/vm/mmap_min_addr 65536 $ cat install_special_mapping.s section .bss resb BSS_SIZE section .text global _start _start: mov eax, __NR_pause int 0x80 $ nasm -D__NR_pause=29 -DBSS_SIZE=0xfffed000 -f elf -o install_special_mapping.o install_special_mapping.s $ ld -m elf_i386 -Ttext=0x10000 -Tbss=0x11000 -o install_special_mapping install_special_mapping.o $ ./install_special_mapping & [1] 14303 $ cat /proc/14303/maps 0000f000-00010000 r-xp 00000000 00:00 0 [vdso] 00010000-00011000 r-xp 00001000 00:19 2453665 /home/taviso/install_special_mapping 00011000-ffffe000 rwxp 00000000 00:00 0 [stack] It's worth noting that Red Hat are shipping with mmap_min_addr set to 4096. Signed-off-by: Tavis Ormandy <taviso@google.com> Acked-by: Kees Cook <kees@ubuntu.com> Acked-by: Robert Swiecki <swiecki@google.com> [ Changed to not drop the error code - akpm ] Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-09 17:29:42 +03:00
out:
mm: use helper functions for allocating and freeing vm_area structs The vm_area_struct is one of the most fundamental memory management objects, but the management of it is entirely open-coded evertwhere, ranging from allocation and freeing (using kmem_cache_[z]alloc and kmem_cache_free) to initializing all the fields. We want to unify this in order to end up having some unified initialization of the vmas, and the first step to this is to at least have basic allocation functions. Right now those functions are literally just wrappers around the kmem_cache_*() calls. This is a purely mechanical conversion: # new vma: kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc() # copy old vma kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old) # free vma kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma) to the point where the old vma passed in to the vm_area_dup() function isn't even used yet (because I've left all the old manual initialization alone). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-21 23:48:51 +03:00
vm_area_free(vma);
mm: Add new func _install_special_mapping() to mmap.c The _install_special_mapping() is the new base function for install_special_mapping(). This function will return a pointer of the created VMA or a error code in an ERR_PTR() This new function will be needed by the for the vdso 32 bit support to map the additonal vvar and hpet pages into the 32 bit address space. This will be done with io_remap_pfn_range() and remap_pfn_range, which requieres a vm_area_struct. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-3-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-03-18 02:22:02 +04:00
return ERR_PTR(ret);
}
x86/arch_prctl/vdso: Add ARCH_MAP_VDSO_* Add API to change vdso blob type with arch_prctl. As this is usefull only by needs of CRIU, expose this interface under CONFIG_CHECKPOINT_RESTORE. Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: 0x7f454c46@gmail.com Cc: oleg@redhat.com Cc: linux-mm@kvack.org Cc: gorcunov@openvz.org Cc: xemul@virtuozzo.com Link: http://lkml.kernel.org/r/20160905133308.28234-4-dsafonov@virtuozzo.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-05 16:33:05 +03:00
bool vma_is_special_mapping(const struct vm_area_struct *vma,
const struct vm_special_mapping *sm)
{
return vma->vm_private_data == sm &&
(vma->vm_ops == &special_mapping_vmops ||
vma->vm_ops == &legacy_special_mapping_vmops);
}
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
/*
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* Called with mm->mmap_lock held for writing.
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
* Insert a new vma covering the given region, with the given flags.
* Its pages are supplied by the given array of struct page *.
* The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
* The region past the last page supplied will always produce SIGBUS.
* The array pointer and the pages it points to are assumed to stay alive
* for as long as this mapping might exist.
*/
struct vm_area_struct *_install_special_mapping(
struct mm_struct *mm,
unsigned long addr, unsigned long len,
unsigned long vm_flags, const struct vm_special_mapping *spec)
{
mm/mmap.c: change __install_special_mapping() args order Make __install_special_mapping() args order match the caller, so the caller can pass their register args directly to callee with no touch. For most of architectures, args (at least the first 5th args) are in registers, so this change will have effect on most of architectures. For -O2, __install_special_mapping() may be inlined under most of architectures, but for -Os, it should not. So this change can get a little better performance for -Os, at least. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:41 +03:00
return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec,
&special_mapping_vmops);
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
}
mm: Add new func _install_special_mapping() to mmap.c The _install_special_mapping() is the new base function for install_special_mapping(). This function will return a pointer of the created VMA or a error code in an ERR_PTR() This new function will be needed by the for the vdso 32 bit support to map the additonal vvar and hpet pages into the 32 bit address space. This will be done with io_remap_pfn_range() and remap_pfn_range, which requieres a vm_area_struct. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-3-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-03-18 02:22:02 +04:00
int install_special_mapping(struct mm_struct *mm,
unsigned long addr, unsigned long len,
unsigned long vm_flags, struct page **pages)
{
x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-20 02:58:33 +04:00
struct vm_area_struct *vma = __install_special_mapping(
mm/mmap.c: change __install_special_mapping() args order Make __install_special_mapping() args order match the caller, so the caller can pass their register args directly to callee with no touch. For most of architectures, args (at least the first 5th args) are in registers, so this change will have effect on most of architectures. For -O2, __install_special_mapping() may be inlined under most of architectures, but for -Os, it should not. So this change can get a little better performance for -Os, at least. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 05:48:41 +03:00
mm, addr, len, vm_flags, (void *)pages,
&legacy_special_mapping_vmops);
mm: Add new func _install_special_mapping() to mmap.c The _install_special_mapping() is the new base function for install_special_mapping(). This function will return a pointer of the created VMA or a error code in an ERR_PTR() This new function will be needed by the for the vdso 32 bit support to map the additonal vvar and hpet pages into the 32 bit address space. This will be done with io_remap_pfn_range() and remap_pfn_range, which requieres a vm_area_struct. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-3-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-03-18 02:22:02 +04:00
mm/mmap.c: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO Fix a coccinelle error regarding usage of IS_ERR and PTR_ERR instead of PTR_ERR_OR_ZERO. Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-05 03:07:05 +04:00
return PTR_ERR_OR_ZERO(vma);
[PATCH] Add install_special_mapping This patch adds a utility function install_special_mapping, for creating a special vma using a fixed set of preallocated pages as backing, such as for a vDSO. This consolidates some nearly identical code used for vDSO mapping reimplemented for different architectures. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09 01:20:41 +03:00
}
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
static DEFINE_MUTEX(mm_all_locks_mutex);
lockdep: annotate mm_take_all_locks() The nesting is correct due to holding mmap_sem, use the new annotation to annotate this. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 11:30:25 +04:00
static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
{
lib/interval_tree: fast overlap detection Allow interval trees to quickly check for overlaps to avoid unnecesary tree lookups in interval_tree_iter_first(). As of this patch, all interval tree flavors will require using a 'rb_root_cached' such that we can have the leftmost node easily available. While most users will make use of this feature, those with special functions (in addition to the generic insert, delete, search calls) will avoid using the cached option as they can do funky things with insertions -- for example, vma_interval_tree_insert_after(). [jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()] Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Jason Wang <jasowang@redhat.com> Cc: Christian Benvenuti <benve@cisco.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-09 02:15:08 +03:00
if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) {
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
/*
* The LSB of head.next can't change from under us
* because we hold the mm_all_locks_mutex.
*/
mmap locking API: rename mmap_sem to mmap_lock Rename the mmap_sem field to mmap_lock. Any new uses of this lock should now go through the new mmap locking api. The mmap_lock is still implemented as a rwsem, though this could change in the future. [akpm@linux-foundation.org: fix it for mm-gup-might_lock_readmmap_sem-in-get_user_pages_fast.patch] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-11-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:47 +03:00
down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock);
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
/*
* We can safely modify head.next after taking the
mm/rmap: Convert the struct anon_vma::mutex to an rwsem Convert the struct anon_vma::mutex to an rwsem, which will help in solving a page-migration scalability problem. (Addressed in a separate patch.) The conversion is simple and straightforward: in every case where we mutex_lock()ed we'll now down_write(). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Turner <pjt@google.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-02 23:56:46 +04:00
* anon_vma->root->rwsem. If some other vma in this mm shares
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
* the same anon_vma we won't take it again.
*
* No need of atomic instructions here, head.next
* can't change from under us thanks to the
mm/rmap: Convert the struct anon_vma::mutex to an rwsem Convert the struct anon_vma::mutex to an rwsem, which will help in solving a page-migration scalability problem. (Addressed in a separate patch.) The conversion is simple and straightforward: in every case where we mutex_lock()ed we'll now down_write(). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Turner <pjt@google.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-02 23:56:46 +04:00
* anon_vma->root->rwsem.
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
*/
if (__test_and_set_bit(0, (unsigned long *)
lib/interval_tree: fast overlap detection Allow interval trees to quickly check for overlaps to avoid unnecesary tree lookups in interval_tree_iter_first(). As of this patch, all interval tree flavors will require using a 'rb_root_cached' such that we can have the leftmost node easily available. While most users will make use of this feature, those with special functions (in addition to the generic insert, delete, search calls) will avoid using the cached option as they can do funky things with insertions -- for example, vma_interval_tree_insert_after(). [jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()] Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Jason Wang <jasowang@redhat.com> Cc: Christian Benvenuti <benve@cisco.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-09 02:15:08 +03:00
&anon_vma->root->rb_root.rb_root.rb_node))
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
BUG();
}
}
lockdep: annotate mm_take_all_locks() The nesting is correct due to holding mmap_sem, use the new annotation to annotate this. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 11:30:25 +04:00
static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
{
if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
/*
* AS_MM_ALL_LOCKS can't change from under us because
* we hold the mm_all_locks_mutex.
*
* Operations on ->flags have to be atomic because
* even if AS_MM_ALL_LOCKS is stable thanks to the
* mm_all_locks_mutex, there may be other cpus
* changing other bitflags in parallel to us.
*/
if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
BUG();
mmap locking API: rename mmap_sem to mmap_lock Rename the mmap_sem field to mmap_lock. Any new uses of this lock should now go through the new mmap locking api. The mmap_lock is still implemented as a rwsem, though this could change in the future. [akpm@linux-foundation.org: fix it for mm-gup-might_lock_readmmap_sem-in-get_user_pages_fast.patch] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-11-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:47 +03:00
down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock);
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
}
}
/*
* This operation locks against the VM for all pte/vma/mm related
* operations that could ever happen on a certain mm. This includes
* vmtruncate, try_to_unmap, and all page faults.
*
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* The caller must take the mmap_lock in write mode before calling
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
* mm_take_all_locks(). The caller isn't allowed to release the
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* mmap_lock until mm_drop_all_locks() returns.
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
*
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* mmap_lock in write mode is required in order to block all operations
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
* that could modify pagetables and free pages without need of
rmap: drop support of non-linear mappings We don't create non-linear mappings anymore. Let's drop code which handles them in rmap. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 01:09:59 +03:00
* altering the vma layout. It's also needed in write mode to avoid new
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
* anon_vmas to be associated with existing vmas.
*
* A single task can't take more than one mm_take_all_locks() in a row
* or it would deadlock.
*
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
* The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
* mapping->flags avoid to take the same lock twice, if more than one
* vma in this mm is backed by the same anon_vma or address_space.
*
mm: fix locking order in mm_take_all_locks() Dmitry Vyukov has reported[1] possible deadlock (triggered by his syzkaller fuzzer): Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hugetlbfs_i_mmap_rwsem_key); lock(&mapping->i_mmap_rwsem); lock(&hugetlbfs_i_mmap_rwsem_key); lock(&mapping->i_mmap_rwsem); Both traces points to mm_take_all_locks() as a source of the problem. It doesn't take care about ordering or hugetlbfs_i_mmap_rwsem_key (aka mapping->i_mmap_rwsem for hugetlb mapping) vs. i_mmap_rwsem. huge_pmd_share() does memory allocation under hugetlbfs_i_mmap_rwsem_key and allocator can take i_mmap_rwsem if it hit reclaim. So we need to take i_mmap_rwsem from all hugetlb VMAs before taking i_mmap_rwsem from rest of VMAs. The patch also documents locking order for hugetlbfs_i_mmap_rwsem_key. [1] http://lkml.kernel.org/r/CACT4Y+Zu95tBs-0EvdiAKzUOsb4tczRRfCRTpLr4bg_OP9HuVg@mail.gmail.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-16 03:57:31 +03:00
* We take locks in following order, accordingly to comment at beginning
* of mm/rmap.c:
* - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for
* hugetlb mapping);
* - all i_mmap_rwsem locks;
* - all anon_vma->rwseml
*
* We can take all locks within these types randomly because the VM code
* doesn't nest them and we protected from parallel mm_take_all_locks() by
* mm_all_locks_mutex.
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
*
* mm_take_all_locks() and mm_drop_all_locks are expensive operations
* that may have to take thousand of locks.
*
* mm_take_all_locks() can fail if it's interrupted by signals.
*/
int mm_take_all_locks(struct mm_struct *mm)
{
struct vm_area_struct *vma;
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
struct anon_vma_chain *avc;
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
BUG_ON(mmap_read_trylock(mm));
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
mutex_lock(&mm_all_locks_mutex);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (signal_pending(current))
goto out_unlock;
mm: fix locking order in mm_take_all_locks() Dmitry Vyukov has reported[1] possible deadlock (triggered by his syzkaller fuzzer): Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hugetlbfs_i_mmap_rwsem_key); lock(&mapping->i_mmap_rwsem); lock(&hugetlbfs_i_mmap_rwsem_key); lock(&mapping->i_mmap_rwsem); Both traces points to mm_take_all_locks() as a source of the problem. It doesn't take care about ordering or hugetlbfs_i_mmap_rwsem_key (aka mapping->i_mmap_rwsem for hugetlb mapping) vs. i_mmap_rwsem. huge_pmd_share() does memory allocation under hugetlbfs_i_mmap_rwsem_key and allocator can take i_mmap_rwsem if it hit reclaim. So we need to take i_mmap_rwsem from all hugetlb VMAs before taking i_mmap_rwsem from rest of VMAs. The patch also documents locking order for hugetlbfs_i_mmap_rwsem_key. [1] http://lkml.kernel.org/r/CACT4Y+Zu95tBs-0EvdiAKzUOsb4tczRRfCRTpLr4bg_OP9HuVg@mail.gmail.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-16 03:57:31 +03:00
if (vma->vm_file && vma->vm_file->f_mapping &&
is_vm_hugetlb_page(vma))
vm_lock_mapping(mm, vma->vm_file->f_mapping);
}
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (signal_pending(current))
goto out_unlock;
if (vma->vm_file && vma->vm_file->f_mapping &&
!is_vm_hugetlb_page(vma))
lockdep: annotate mm_take_all_locks() The nesting is correct due to holding mmap_sem, use the new annotation to annotate this. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 11:30:25 +04:00
vm_lock_mapping(mm, vma->vm_file->f_mapping);
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
}
mm: fix mm_take_all_locks() locking order Lockdep spotted: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.27-rc1 #270 ------------------------------------------------------- qemu-kvm/2033 is trying to acquire lock: (&inode->i_data.i_mmap_lock){----}, at: [<ffffffff802996cc>] mm_take_all_locks+0xc2/0xea but task is already holding lock: (&anon_vma->lock){----}, at: [<ffffffff8029967a>] mm_take_all_locks+0x70/0xea which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&anon_vma->lock){----}: [<ffffffff8025cd37>] __lock_acquire+0x11be/0x14d2 [<ffffffff8025d0a9>] lock_acquire+0x5e/0x7a [<ffffffff804c655b>] _spin_lock+0x3b/0x47 [<ffffffff8029a2ef>] vma_adjust+0x200/0x444 [<ffffffff8029a662>] split_vma+0x12f/0x146 [<ffffffff8029bc60>] mprotect_fixup+0x13c/0x536 [<ffffffff8029c203>] sys_mprotect+0x1a9/0x21e [<ffffffff8020c0db>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff -> #0 (&inode->i_data.i_mmap_lock){----}: [<ffffffff8025ca54>] __lock_acquire+0xedb/0x14d2 [<ffffffff8025d397>] lock_release_non_nested+0x1c2/0x219 [<ffffffff8025d515>] lock_release+0x127/0x14a [<ffffffff804c6403>] _spin_unlock+0x1e/0x50 [<ffffffff802995d9>] mm_drop_all_locks+0x7f/0xb0 [<ffffffff802a965d>] do_mmu_notifier_register+0xe2/0x112 [<ffffffff802a96a8>] mmu_notifier_register+0xe/0x10 [<ffffffffa0043b6b>] kvm_dev_ioctl+0x11e/0x287 [kvm] [<ffffffff802bd0ca>] vfs_ioctl+0x2a/0x78 [<ffffffff802bd36f>] do_vfs_ioctl+0x257/0x274 [<ffffffff802bd3e1>] sys_ioctl+0x55/0x78 [<ffffffff8020c0db>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff other info that might help us debug this: 5 locks held by qemu-kvm/2033: #0: (&mm->mmap_sem){----}, at: [<ffffffff802a95d0>] do_mmu_notifier_register+0x55/0x112 #1: (mm_all_locks_mutex){--..}, at: [<ffffffff8029963e>] mm_take_all_locks+0x34/0xea #2: (&anon_vma->lock){----}, at: [<ffffffff8029967a>] mm_take_all_locks+0x70/0xea #3: (&anon_vma->lock){----}, at: [<ffffffff8029967a>] mm_take_all_locks+0x70/0xea #4: (&anon_vma->lock){----}, at: [<ffffffff8029967a>] mm_take_all_locks+0x70/0xea stack backtrace: Pid: 2033, comm: qemu-kvm Not tainted 2.6.27-rc1 #270 Call Trace: [<ffffffff8025b7c7>] print_circular_bug_tail+0xb8/0xc3 [<ffffffff8025ca54>] __lock_acquire+0xedb/0x14d2 [<ffffffff80259bb1>] ? add_lock_to_list+0x7e/0xad [<ffffffff8029967a>] ? mm_take_all_locks+0x70/0xea [<ffffffff8029967a>] ? mm_take_all_locks+0x70/0xea [<ffffffff8025d397>] lock_release_non_nested+0x1c2/0x219 [<ffffffff802996cc>] ? mm_take_all_locks+0xc2/0xea [<ffffffff802996cc>] ? mm_take_all_locks+0xc2/0xea [<ffffffff8025b202>] ? trace_hardirqs_on_caller+0x4d/0x115 [<ffffffff802995d9>] ? mm_drop_all_locks+0x7f/0xb0 [<ffffffff8025d515>] lock_release+0x127/0x14a [<ffffffff804c6403>] _spin_unlock+0x1e/0x50 [<ffffffff802995d9>] mm_drop_all_locks+0x7f/0xb0 [<ffffffff802a965d>] do_mmu_notifier_register+0xe2/0x112 [<ffffffff802a96a8>] mmu_notifier_register+0xe/0x10 [<ffffffffa0043b6b>] kvm_dev_ioctl+0x11e/0x287 [kvm] [<ffffffff8033f9f2>] ? file_has_perm+0x83/0x8e [<ffffffff802bd0ca>] vfs_ioctl+0x2a/0x78 [<ffffffff802bd36f>] do_vfs_ioctl+0x257/0x274 [<ffffffff802bd3e1>] sys_ioctl+0x55/0x78 [<ffffffff8020c0db>] system_call_fastpath+0x16/0x1b Which the locking hierarchy in mm/rmap.c confirms as valid. Fix this by first taking all the mapping->i_mmap_lock instances and then take all anon_vma->lock instances. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 11:30:25 +04:00
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (signal_pending(current))
goto out_unlock;
if (vma->anon_vma)
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
vm_lock_anon_vma(mm, avc->anon_vma);
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
}
mm: fix mm_take_all_locks() locking order Lockdep spotted: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.27-rc1 #270 ------------------------------------------------------- qemu-kvm/2033 is trying to acquire lock: (&inode->i_data.i_mmap_lock){----}, at: [<ffffffff802996cc>] mm_take_all_locks+0xc2/0xea but task is already holding lock: (&anon_vma->lock){----}, at: [<ffffffff8029967a>] mm_take_all_locks+0x70/0xea which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&anon_vma->lock){----}: [<ffffffff8025cd37>] __lock_acquire+0x11be/0x14d2 [<ffffffff8025d0a9>] lock_acquire+0x5e/0x7a [<ffffffff804c655b>] _spin_lock+0x3b/0x47 [<ffffffff8029a2ef>] vma_adjust+0x200/0x444 [<ffffffff8029a662>] split_vma+0x12f/0x146 [<ffffffff8029bc60>] mprotect_fixup+0x13c/0x536 [<ffffffff8029c203>] sys_mprotect+0x1a9/0x21e [<ffffffff8020c0db>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff -> #0 (&inode->i_data.i_mmap_lock){----}: [<ffffffff8025ca54>] __lock_acquire+0xedb/0x14d2 [<ffffffff8025d397>] lock_release_non_nested+0x1c2/0x219 [<ffffffff8025d515>] lock_release+0x127/0x14a [<ffffffff804c6403>] _spin_unlock+0x1e/0x50 [<ffffffff802995d9>] mm_drop_all_locks+0x7f/0xb0 [<ffffffff802a965d>] do_mmu_notifier_register+0xe2/0x112 [<ffffffff802a96a8>] mmu_notifier_register+0xe/0x10 [<ffffffffa0043b6b>] kvm_dev_ioctl+0x11e/0x287 [kvm] [<ffffffff802bd0ca>] vfs_ioctl+0x2a/0x78 [<ffffffff802bd36f>] do_vfs_ioctl+0x257/0x274 [<ffffffff802bd3e1>] sys_ioctl+0x55/0x78 [<ffffffff8020c0db>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff other info that might help us debug this: 5 locks held by qemu-kvm/2033: #0: (&mm->mmap_sem){----}, at: [<ffffffff802a95d0>] do_mmu_notifier_register+0x55/0x112 #1: (mm_all_locks_mutex){--..}, at: [<ffffffff8029963e>] mm_take_all_locks+0x34/0xea #2: (&anon_vma->lock){----}, at: [<ffffffff8029967a>] mm_take_all_locks+0x70/0xea #3: (&anon_vma->lock){----}, at: [<ffffffff8029967a>] mm_take_all_locks+0x70/0xea #4: (&anon_vma->lock){----}, at: [<ffffffff8029967a>] mm_take_all_locks+0x70/0xea stack backtrace: Pid: 2033, comm: qemu-kvm Not tainted 2.6.27-rc1 #270 Call Trace: [<ffffffff8025b7c7>] print_circular_bug_tail+0xb8/0xc3 [<ffffffff8025ca54>] __lock_acquire+0xedb/0x14d2 [<ffffffff80259bb1>] ? add_lock_to_list+0x7e/0xad [<ffffffff8029967a>] ? mm_take_all_locks+0x70/0xea [<ffffffff8029967a>] ? mm_take_all_locks+0x70/0xea [<ffffffff8025d397>] lock_release_non_nested+0x1c2/0x219 [<ffffffff802996cc>] ? mm_take_all_locks+0xc2/0xea [<ffffffff802996cc>] ? mm_take_all_locks+0xc2/0xea [<ffffffff8025b202>] ? trace_hardirqs_on_caller+0x4d/0x115 [<ffffffff802995d9>] ? mm_drop_all_locks+0x7f/0xb0 [<ffffffff8025d515>] lock_release+0x127/0x14a [<ffffffff804c6403>] _spin_unlock+0x1e/0x50 [<ffffffff802995d9>] mm_drop_all_locks+0x7f/0xb0 [<ffffffff802a965d>] do_mmu_notifier_register+0xe2/0x112 [<ffffffff802a96a8>] mmu_notifier_register+0xe/0x10 [<ffffffffa0043b6b>] kvm_dev_ioctl+0x11e/0x287 [kvm] [<ffffffff8033f9f2>] ? file_has_perm+0x83/0x8e [<ffffffff802bd0ca>] vfs_ioctl+0x2a/0x78 [<ffffffff802bd36f>] do_vfs_ioctl+0x257/0x274 [<ffffffff802bd3e1>] sys_ioctl+0x55/0x78 [<ffffffff8020c0db>] system_call_fastpath+0x16/0x1b Which the locking hierarchy in mm/rmap.c confirms as valid. Fix this by first taking all the mapping->i_mmap_lock instances and then take all anon_vma->lock instances. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 11:30:25 +04:00
mm/mmap.c: eliminate the ret variable from mm_take_all_locks() The ret variable is really not needed in mm_take_all_locks(). Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-01 04:08:59 +04:00
return 0;
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
out_unlock:
mm/mmap.c: eliminate the ret variable from mm_take_all_locks() The ret variable is really not needed in mm_take_all_locks(). Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-01 04:08:59 +04:00
mm_drop_all_locks(mm);
return -EINTR;
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
}
static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
{
lib/interval_tree: fast overlap detection Allow interval trees to quickly check for overlaps to avoid unnecesary tree lookups in interval_tree_iter_first(). As of this patch, all interval tree flavors will require using a 'rb_root_cached' such that we can have the leftmost node easily available. While most users will make use of this feature, those with special functions (in addition to the generic insert, delete, search calls) will avoid using the cached option as they can do funky things with insertions -- for example, vma_interval_tree_insert_after(). [jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()] Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Jason Wang <jasowang@redhat.com> Cc: Christian Benvenuti <benve@cisco.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-09 02:15:08 +03:00
if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) {
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
/*
* The LSB of head.next can't change to 0 from under
* us because we hold the mm_all_locks_mutex.
*
* We must however clear the bitflag before unlocking
mm anon rmap: replace same_anon_vma linked list with an interval tree. When a large VMA (anon or private file mapping) is first touched, which will populate its anon_vma field, and then split into many regions through the use of mprotect(), the original anon_vma ends up linking all of the vmas on a linked list. This can cause rmap to become inefficient, as we have to walk potentially thousands of irrelevent vmas before finding the one a given anon page might fall into. By replacing the same_anon_vma linked list with an interval tree (where each avc's interval is determined by its vma's start and last pgoffs), we can make rmap efficient for this use case again. While the change is large, all of its pieces are fairly simple. Most places that were walking the same_anon_vma list were looking for a known pgoff, so they can just use the anon_vma_interval_tree_foreach() interval tree iterator instead. The exception here is ksm, where the page's index is not known. It would probably be possible to rework ksm so that the index would be known, but for now I have decided to keep things simple and just walk the entirety of the interval tree there. When updating vma's that already have an anon_vma assigned, we must take care to re-index the corresponding avc's on their interval tree. This is done through the use of anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma(), which remove the avc's from their interval tree before the update and re-insert them after the update. The anon_vma stays locked during the update, so there is no chance that rmap would miss the vmas that are being updated. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 03:31:39 +04:00
* the vma so the users using the anon_vma->rb_root will
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
* never see our bitflag.
*
* No need of atomic instructions here, head.next
* can't change from under us until we release the
mm/rmap: Convert the struct anon_vma::mutex to an rwsem Convert the struct anon_vma::mutex to an rwsem, which will help in solving a page-migration scalability problem. (Addressed in a separate patch.) The conversion is simple and straightforward: in every case where we mutex_lock()ed we'll now down_write(). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Turner <pjt@google.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-02 23:56:46 +04:00
* anon_vma->root->rwsem.
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
*/
if (!__test_and_clear_bit(0, (unsigned long *)
lib/interval_tree: fast overlap detection Allow interval trees to quickly check for overlaps to avoid unnecesary tree lookups in interval_tree_iter_first(). As of this patch, all interval tree flavors will require using a 'rb_root_cached' such that we can have the leftmost node easily available. While most users will make use of this feature, those with special functions (in addition to the generic insert, delete, search calls) will avoid using the cached option as they can do funky things with insertions -- for example, vma_interval_tree_insert_after(). [jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()] Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Jason Wang <jasowang@redhat.com> Cc: Christian Benvenuti <benve@cisco.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-09 02:15:08 +03:00
&anon_vma->root->rb_root.rb_root.rb_node))
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
BUG();
mm/rmap: rename anon_vma_unlock() => anon_vma_unlock_write() The comment in commit 4fc3f1d66b1e ("mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable") says: | Rename anon_vma_[un]lock() => anon_vma_[un]lock_write(), | to make it clearer that it's an exclusive write-lock in | that case - suggested by Rik van Riel. But that commit renames only anon_vma_lock() Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Ingo Molnar <mingo@kernel.org> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 04:34:40 +04:00
anon_vma_unlock_write(anon_vma);
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
}
}
static void vm_unlock_mapping(struct address_space *mapping)
{
if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
/*
* AS_MM_ALL_LOCKS can't change to 0 from under us
* because we hold the mm_all_locks_mutex.
*/
mm: use new helper functions around the i_mmap_mutex Convert all open coded mutex_lock/unlock calls to the i_mmap_[lock/unlock]_write() helpers. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 03:54:21 +03:00
i_mmap_unlock_write(mapping);
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
&mapping->flags))
BUG();
}
}
/*
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:54 +03:00
* The mmap_lock cannot be released by the caller until
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
* mm_drop_all_locks() returns.
*/
void mm_drop_all_locks(struct mm_struct *mm)
{
struct vm_area_struct *vma;
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
struct anon_vma_chain *avc;
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 07:33:25 +03:00
BUG_ON(mmap_read_trylock(mm));
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (vma->anon_vma)
mm: change anon_vma linking to fix multi-process server scalability issue The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 00:42:07 +03:00
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
vm_unlock_anon_vma(avc->anon_vma);
mmu-notifiers: add mm_take_all_locks() operation mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kanoj Sarcar <kanojsarcar@yahoo.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Steve Wise <swise@opengridcomputing.com> Cc: Avi Kivity <avi@qumranet.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Izik Eidus <izike@qumranet.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-29 02:46:26 +04:00
if (vma->vm_file && vma->vm_file->f_mapping)
vm_unlock_mapping(vma->vm_file->f_mapping);
}
mutex_unlock(&mm_all_locks_mutex);
}
NOMMU: Make VMAs per MM as for MMU-mode linux Make VMAs per mm_struct as for MMU-mode linux. This solves two problems: (1) In SYSV SHM where nattch for a segment does not reflect the number of shmat's (and forks) done. (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an exec'ing process when VM_EXECUTABLE is specified, regardless of the fact that a VMA might be shared and already have its vm_mm assigned to another process or a dead process. A new struct (vm_region) is introduced to track a mapped region and to remember the circumstances under which it may be shared and the vm_list_struct structure is discarded as it's no longer required. This patch makes the following additional changes: (1) Regions are now allocated with alloc_pages() rather than kmalloc() and with no recourse to __GFP_COMP, so the pages are not composite. Instead, each page has a reference on it held by the region. Anything else that is interested in such a page will have to get a reference on it to retain it. When the pages are released due to unmapping, each page is passed to put_page() and will be freed when the page usage count reaches zero. (2) Excess pages are trimmed after an allocation as the allocation must be made as a power-of-2 quantity of pages. (3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may end up with overlapping VMAs within the tree, the VMA struct address is appended to the sort key. (4) Non-anonymous VMAs are now added to the backing inode's prio list. (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of the backing region. The VMA and region structs will be split if necessary. (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory segment instead of all the attachments at that addresss. Multiple shmat()'s return the same address under NOMMU-mode instead of different virtual addresses as under MMU-mode. (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode. (8) /proc/maps is now the global list of mapped regions, and may list bits that aren't actually mapped anywhere. (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount of RAM currently allocated by mmap to hold mappable regions that can't be mapped directly. These are copies of the backing device or file if not anonymous. These changes make NOMMU mode more similar to MMU mode. The downside is that NOMMU mode requires some extra memory to track things over NOMMU without this patch (VMAs are no longer shared, and there are now region structs). Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Mike Frysinger <vapier.adi@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org>
2009-01-08 15:04:47 +03:00
/*
mm: fix comments for mmap_init() mmap_init() is no longer associated with VMA slab. So fix it. Link: http://lkml.kernel.org/r/1485182601-9294-1-git-send-email-iamyooon@gmail.com Signed-off-by: seokhoon.yoon <iamyooon@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25 01:56:44 +03:00
* initialise the percpu counter for VM
NOMMU: Make VMAs per MM as for MMU-mode linux Make VMAs per mm_struct as for MMU-mode linux. This solves two problems: (1) In SYSV SHM where nattch for a segment does not reflect the number of shmat's (and forks) done. (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an exec'ing process when VM_EXECUTABLE is specified, regardless of the fact that a VMA might be shared and already have its vm_mm assigned to another process or a dead process. A new struct (vm_region) is introduced to track a mapped region and to remember the circumstances under which it may be shared and the vm_list_struct structure is discarded as it's no longer required. This patch makes the following additional changes: (1) Regions are now allocated with alloc_pages() rather than kmalloc() and with no recourse to __GFP_COMP, so the pages are not composite. Instead, each page has a reference on it held by the region. Anything else that is interested in such a page will have to get a reference on it to retain it. When the pages are released due to unmapping, each page is passed to put_page() and will be freed when the page usage count reaches zero. (2) Excess pages are trimmed after an allocation as the allocation must be made as a power-of-2 quantity of pages. (3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may end up with overlapping VMAs within the tree, the VMA struct address is appended to the sort key. (4) Non-anonymous VMAs are now added to the backing inode's prio list. (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of the backing region. The VMA and region structs will be split if necessary. (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory segment instead of all the attachments at that addresss. Multiple shmat()'s return the same address under NOMMU-mode instead of different virtual addresses as under MMU-mode. (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode. (8) /proc/maps is now the global list of mapped regions, and may list bits that aren't actually mapped anywhere. (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount of RAM currently allocated by mmap to hold mappable regions that can't be mapped directly. These are copies of the backing device or file if not anonymous. These changes make NOMMU mode more similar to MMU mode. The downside is that NOMMU mode requires some extra memory to track things over NOMMU without this patch (VMAs are no longer shared, and there are now region structs). Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Mike Frysinger <vapier.adi@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org>
2009-01-08 15:04:47 +03:00
*/
void __init mmap_init(void)
{
mm: fix Committed_AS underflow on large NR_CPUS environment The Committed_AS field can underflow in certain situations: > # while true; do cat /proc/meminfo | grep _AS; sleep 1; done | uniq -c > 1 Committed_AS: 18446744073709323392 kB > 11 Committed_AS: 18446744073709455488 kB > 6 Committed_AS: 35136 kB > 5 Committed_AS: 18446744073709454400 kB > 7 Committed_AS: 35904 kB > 3 Committed_AS: 18446744073709453248 kB > 2 Committed_AS: 34752 kB > 9 Committed_AS: 18446744073709453248 kB > 8 Committed_AS: 34752 kB > 3 Committed_AS: 18446744073709320960 kB > 7 Committed_AS: 18446744073709454080 kB > 3 Committed_AS: 18446744073709320960 kB > 5 Committed_AS: 18446744073709454080 kB > 6 Committed_AS: 18446744073709320960 kB Because NR_CPUS can be greater than 1000 and meminfo_proc_show() does not check for underflow. But NR_CPUS proportional isn't good calculation. In general, possibility of lock contention is proportional to the number of online cpus, not theorical maximum cpus (NR_CPUS). The current kernel has generic percpu-counter stuff. using it is right way. it makes code simplify and percpu_counter_read_positive() don't make underflow issue. Reported-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Eric B Munson <ebmunson@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@kernel.org> [All kernel versions] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-01 02:08:51 +04:00
int ret;
percpu_counter: add @gfp to percpu_counter_init() Percpu allocator now supports allocation mask. Add @gfp to percpu_counter_init() so that !GFP_KERNEL allocation masks can be used with percpu_counters too. We could have left percpu_counter_init() alone and added percpu_counter_init_gfp(); however, the number of users isn't that high and introducing _gfp variants to all percpu data structures would be quite ugly, so let's just do the conversion. This is the one with the most users. Other percpu data structures are a lot easier to convert. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jan Kara <jack@suse.cz> Acked-by: "David S. Miller" <davem@davemloft.net> Cc: x86@kernel.org Cc: Jens Axboe <axboe@kernel.dk> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org>
2014-09-08 04:51:29 +04:00
ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
mm: fix Committed_AS underflow on large NR_CPUS environment The Committed_AS field can underflow in certain situations: > # while true; do cat /proc/meminfo | grep _AS; sleep 1; done | uniq -c > 1 Committed_AS: 18446744073709323392 kB > 11 Committed_AS: 18446744073709455488 kB > 6 Committed_AS: 35136 kB > 5 Committed_AS: 18446744073709454400 kB > 7 Committed_AS: 35904 kB > 3 Committed_AS: 18446744073709453248 kB > 2 Committed_AS: 34752 kB > 9 Committed_AS: 18446744073709453248 kB > 8 Committed_AS: 34752 kB > 3 Committed_AS: 18446744073709320960 kB > 7 Committed_AS: 18446744073709454080 kB > 3 Committed_AS: 18446744073709320960 kB > 5 Committed_AS: 18446744073709454080 kB > 6 Committed_AS: 18446744073709320960 kB Because NR_CPUS can be greater than 1000 and meminfo_proc_show() does not check for underflow. But NR_CPUS proportional isn't good calculation. In general, possibility of lock contention is proportional to the number of online cpus, not theorical maximum cpus (NR_CPUS). The current kernel has generic percpu-counter stuff. using it is right way. it makes code simplify and percpu_counter_read_positive() don't make underflow issue. Reported-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Eric B Munson <ebmunson@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@kernel.org> [All kernel versions] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-01 02:08:51 +04:00
VM_BUG_ON(ret);
NOMMU: Make VMAs per MM as for MMU-mode linux Make VMAs per mm_struct as for MMU-mode linux. This solves two problems: (1) In SYSV SHM where nattch for a segment does not reflect the number of shmat's (and forks) done. (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an exec'ing process when VM_EXECUTABLE is specified, regardless of the fact that a VMA might be shared and already have its vm_mm assigned to another process or a dead process. A new struct (vm_region) is introduced to track a mapped region and to remember the circumstances under which it may be shared and the vm_list_struct structure is discarded as it's no longer required. This patch makes the following additional changes: (1) Regions are now allocated with alloc_pages() rather than kmalloc() and with no recourse to __GFP_COMP, so the pages are not composite. Instead, each page has a reference on it held by the region. Anything else that is interested in such a page will have to get a reference on it to retain it. When the pages are released due to unmapping, each page is passed to put_page() and will be freed when the page usage count reaches zero. (2) Excess pages are trimmed after an allocation as the allocation must be made as a power-of-2 quantity of pages. (3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may end up with overlapping VMAs within the tree, the VMA struct address is appended to the sort key. (4) Non-anonymous VMAs are now added to the backing inode's prio list. (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of the backing region. The VMA and region structs will be split if necessary. (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory segment instead of all the attachments at that addresss. Multiple shmat()'s return the same address under NOMMU-mode instead of different virtual addresses as under MMU-mode. (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode. (8) /proc/maps is now the global list of mapped regions, and may list bits that aren't actually mapped anywhere. (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount of RAM currently allocated by mmap to hold mappable regions that can't be mapped directly. These are copies of the backing device or file if not anonymous. These changes make NOMMU mode more similar to MMU mode. The downside is that NOMMU mode requires some extra memory to track things over NOMMU without this patch (VMAs are no longer shared, and there are now region structs). Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Mike Frysinger <vapier.adi@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org>
2009-01-08 15:04:47 +03:00
}
mm: limit growth of 3% hardcoded other user reserve Add user_reserve_kbytes knob. Limit the growth of the memory reserved for other user processes to min(3% current process size, user_reserve_pages). Only about 8MB is necessary to enable recovery in the default mode, and only a few hundred MB are required even when overcommit is disabled. user_reserve_pages defaults to min(3% free pages, 128MB) I arrived at 128MB by taking the max VSZ of sshd, login, bash, and top ... then adding the RSS of each. This only affects OVERCOMMIT_NEVER mode. Background 1. user reserve __vm_enough_memory reserves a hardcoded 3% of the current process size for other applications when overcommit is disabled. This was done so that a user could recover if they launched a memory hogging process. Without the reserve, a user would easily run into a message such as: bash: fork: Cannot allocate memory 2. admin reserve Additionally, a hardcoded 3% of free memory is reserved for root in both overcommit 'guess' and 'never' modes. This was intended to prevent a scenario where root-cant-log-in and perform recovery operations. Note that this reserve shrinks, and doesn't guarantee a useful reserve. Motivation The two hardcoded memory reserves should be updated to account for current memory sizes. Also, the admin reserve would be more useful if it didn't shrink too much. When the current code was originally written, 1GB was considered "enterprise". Now the 3% reserve can grow to multiple GB on large memory systems, and it only needs to be a few hundred MB at most to enable a user or admin to recover a system with an unwanted memory hogging process. I've found that reducing these reserves is especially beneficial for a specific type of application load: * single application system * one or few processes (e.g. one per core) * allocating all available memory * not initializing every page immediately * long running I've run scientific clusters with this sort of load. A long running job sometimes failed many hours (weeks of CPU time) into a calculation. They weren't initializing all of their memory immediately, and they weren't using calloc, so I put systems into overcommit 'never' mode. These clusters run diskless and have no swap. However, with the current reserves, a user wishing to allocate as much memory as possible to one process may be prevented from using, for example, almost 2GB out of 32GB. The effect is less, but still significant when a user starts a job with one process per core. I have repeatedly seen a set of processes requesting the same amount of memory fail because one of them could not allocate the amount of memory a user would expect to be able to allocate. For example, Message Passing Interfce (MPI) processes, one per core. And it is similar for other parallel programming frameworks. Changing this reserve code will make the overcommit never mode more useful by allowing applications to allocate nearly all of the available memory. Also, the new admin_reserve_kbytes will be safer than the current behavior since the hardcoded 3% of available memory reserve can shrink to something useless in the case where applications have grabbed all available memory. Risks * "bash: fork: Cannot allocate memory" The downside of the first patch-- which creates a tunable user reserve that is only used in overcommit 'never' mode--is that an admin can set it so low that a user may not be able to kill their process, even if they already have a shell prompt. Of course, a user can get in the same predicament with the current 3% reserve--they just have to launch processes until 3% becomes negligible. * root-cant-log-in problem The second patch, adding the tunable rootuser_reserve_pages, allows the admin to shoot themselves in the foot by setting it too small. They can easily get the system into a state where root-can't-log-in. However, the new admin_reserve_kbytes will be safer than the current behavior since the hardcoded 3% of available memory reserve can shrink to something useless in the case where applications have grabbed all available memory. Alternatives * Memory cgroups provide a more flexible way to limit application memory. Not everyone wants to set up cgroups or deal with their overhead. * We could create a fourth overcommit mode which provides smaller reserves. The size of useful reserves may be drastically different depending on the whether the system is embedded or enterprise. * Force users to initialize all of their memory or use calloc. Some users don't want/expect the system to overcommit when they malloc. Overcommit 'never' mode is for this scenario, and it should work well. The new user and admin reserve tunables are simple to use, with low overhead compared to cgroups. The patches preserve current behavior where 3% of memory is less than 128MB, except that the admin reserve doesn't shrink to an unusable size under pressure. The code allows admins to tune for embedded and enterprise usage. FAQ * How is the root-cant-login problem addressed? What happens if admin_reserve_pages is set to 0? Root is free to shoot themselves in the foot by setting admin_reserve_kbytes too low. On x86_64, the minimum useful reserve is: 8MB for overcommit 'guess' 128MB for overcommit 'never' admin_reserve_pages defaults to min(3% free memory, 8MB) So, anyone switching to 'never' mode needs to adjust admin_reserve_pages. * How do you calculate a minimum useful reserve? A user or the admin needs enough memory to login and perform recovery operations, which includes, at a minimum: sshd or login + bash (or some other shell) + top (or ps, kill, etc.) For overcommit 'guess', we can sum resident set sizes (RSS) because we only need enough memory to handle what the recovery programs will typically use. On x86_64 this is about 8MB. For overcommit 'never', we can take the max of their virtual sizes (VSZ) and add the sum of their RSS. We use VSZ instead of RSS because mode forces us to ensure we can fulfill all of the requested memory allocations-- even if the programs only use a fraction of what they ask for. On x86_64 this is about 128MB. When swap is enabled, reserves are useful even when they are as small as 10MB, regardless of overcommit mode. When both swap and overcommit are disabled, then the admin should tune the reserves higher to be absolutley safe. Over 230MB each was safest in my testing. * What happens if user_reserve_pages is set to 0? Note, this only affects overcomitt 'never' mode. Then a user will be able to allocate all available memory minus admin_reserve_kbytes. However, they will easily see a message such as: "bash: fork: Cannot allocate memory" And they won't be able to recover/kill their application. The admin should be able to recover the system if admin_reserve_kbytes is set appropriately. * What's the difference between overcommit 'guess' and 'never'? "Guess" allows an allocation if there are enough free + reclaimable pages. It has a hardcoded 3% of free pages reserved for root. "Never" allows an allocation if there is enough swap + a configurable percentage (default is 50) of physical RAM. It has a hardcoded 3% of free pages reserved for root, like "Guess" mode. It also has a hardcoded 3% of the current process size reserved for additional applications. * Why is overcommit 'guess' not suitable even when an app eventually writes to every page? It takes free pages, file pages, available swap pages, reclaimable slab pages into consideration. In other words, these are all pages available, then why isn't overcommit suitable? Because it only looks at the present state of the system. It does not take into account the memory that other applications have malloced, but haven't initialized yet. It overcommits the system. Test Summary There was little change in behavior in the default overcommit 'guess' mode with swap enabled before and after the patch. This was expected. Systems run most predictably (i.e. no oom kills) in overcommit 'never' mode with swap enabled. This also allowed the most memory to be allocated to a user application. Overcommit 'guess' mode without swap is a bad idea. It is easy to crash the system. None of the other tested combinations crashed. This matches my experience on the Roadrunner supercomputer. Without the tunable user reserve, a system in overcommit 'never' mode and without swap does not allow the admin to recover, although the admin can. With the new tunable reserves, a system in overcommit 'never' mode and without swap can be configured to: 1. maximize user-allocatable memory, running close to the edge of recoverability 2. maximize recoverability, sacrificing allocatable memory to ensure that a user cannot take down a system Test Description Fedora 18 VM - 4 x86_64 cores, 5725MB RAM, 4GB Swap System is booted into multiuser console mode, with unnecessary services turned off. Caches were dropped before each test. Hogs are user memtester processes that attempt to allocate all free memory as reported by /proc/meminfo In overcommit 'never' mode, memory_ratio=100 Test Results 3.9.0-rc1-mm1 Overcommit | Swap | Hogs | MB Got/Wanted | OOMs | User Recovery | Admin Recovery ---------- ---- ---- ------------- ---- ------------- -------------- guess yes 1 5432/5432 no yes yes guess yes 4 5444/5444 1 yes yes guess no 1 5302/5449 no yes yes guess no 4 - crash no no never yes 1 5460/5460 1 yes yes never yes 4 5460/5460 1 yes yes never no 1 5218/5432 no no yes never no 4 5203/5448 no no yes 3.9.0-rc1-mm1-tunablereserves User and Admin Recovery show their respective reserves, if applicable. Overcommit | Swap | Hogs | MB Got/Wanted | OOMs | User Recovery | Admin Recovery ---------- ---- ---- ------------- ---- ------------- -------------- guess yes 1 5419/5419 no - yes 8MB yes guess yes 4 5436/5436 1 - yes 8MB yes guess no 1 5440/5440 * - yes 8MB yes guess no 4 - crash - no 8MB no * process would successfully mlock, then the oom killer would pick it never yes 1 5446/5446 no 10MB yes 20MB yes never yes 4 5456/5456 no 10MB yes 20MB yes never no 1 5387/5429 no 128MB no 8MB barely never no 1 5323/5428 no 226MB barely 8MB barely never no 1 5323/5428 no 226MB barely 8MB barely never no 1 5359/5448 no 10MB no 10MB barely never no 1 5323/5428 no 0MB no 10MB barely never no 1 5332/5428 no 0MB no 50MB yes never no 1 5293/5429 no 0MB no 90MB yes never no 1 5001/5427 no 230MB yes 338MB yes never no 4* 4998/5424 no 230MB yes 338MB yes * more memtesters were launched, able to allocate approximately another 100MB Future Work - Test larger memory systems. - Test an embedded image. - Test other architectures. - Time malloc microbenchmarks. - Would it be useful to be able to set overcommit policy for each memory cgroup? - Some lines are slightly above 80 chars. Perhaps define a macro to convert between pages and kb? Other places in the kernel do this. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make init_user_reserve() static] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:10 +04:00
/*
* Initialise sysctl_user_reserve_kbytes.
*
* This is intended to prevent a user from starting a single memory hogging
* process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
* mode.
*
* The default value is min(3% of free memory, 128MB)
* 128MB is enough to recover with sshd/login, bash, and top/kill.
*/
mm: reinititalise user and admin reserves if memory is added or removed Alter the admin and user reserves of the previous patches in this series when memory is added or removed. If memory is added and the reserves have been eliminated or increased above the default max, then we'll trust the admin. If memory is removed and there isn't enough free memory, then we need to reset the reserves. Otherwise keep the reserve set by the admin. The reserve reset code is the same as the reserve initialization code. I tested hot addition and removal by triggering it via sysfs. The reserves shrunk when they were set high and memory was removed. They were reset higher when memory was added again. [akpm@linux-foundation.org: use register_hotmemory_notifier()] [akpm@linux-foundation.org: init_user_reserve() and init_admin_reserve can no longer be __meminit] [fengguang.wu@intel.com: make init_reserve_notifier() static] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:12 +04:00
static int init_user_reserve(void)
mm: limit growth of 3% hardcoded other user reserve Add user_reserve_kbytes knob. Limit the growth of the memory reserved for other user processes to min(3% current process size, user_reserve_pages). Only about 8MB is necessary to enable recovery in the default mode, and only a few hundred MB are required even when overcommit is disabled. user_reserve_pages defaults to min(3% free pages, 128MB) I arrived at 128MB by taking the max VSZ of sshd, login, bash, and top ... then adding the RSS of each. This only affects OVERCOMMIT_NEVER mode. Background 1. user reserve __vm_enough_memory reserves a hardcoded 3% of the current process size for other applications when overcommit is disabled. This was done so that a user could recover if they launched a memory hogging process. Without the reserve, a user would easily run into a message such as: bash: fork: Cannot allocate memory 2. admin reserve Additionally, a hardcoded 3% of free memory is reserved for root in both overcommit 'guess' and 'never' modes. This was intended to prevent a scenario where root-cant-log-in and perform recovery operations. Note that this reserve shrinks, and doesn't guarantee a useful reserve. Motivation The two hardcoded memory reserves should be updated to account for current memory sizes. Also, the admin reserve would be more useful if it didn't shrink too much. When the current code was originally written, 1GB was considered "enterprise". Now the 3% reserve can grow to multiple GB on large memory systems, and it only needs to be a few hundred MB at most to enable a user or admin to recover a system with an unwanted memory hogging process. I've found that reducing these reserves is especially beneficial for a specific type of application load: * single application system * one or few processes (e.g. one per core) * allocating all available memory * not initializing every page immediately * long running I've run scientific clusters with this sort of load. A long running job sometimes failed many hours (weeks of CPU time) into a calculation. They weren't initializing all of their memory immediately, and they weren't using calloc, so I put systems into overcommit 'never' mode. These clusters run diskless and have no swap. However, with the current reserves, a user wishing to allocate as much memory as possible to one process may be prevented from using, for example, almost 2GB out of 32GB. The effect is less, but still significant when a user starts a job with one process per core. I have repeatedly seen a set of processes requesting the same amount of memory fail because one of them could not allocate the amount of memory a user would expect to be able to allocate. For example, Message Passing Interfce (MPI) processes, one per core. And it is similar for other parallel programming frameworks. Changing this reserve code will make the overcommit never mode more useful by allowing applications to allocate nearly all of the available memory. Also, the new admin_reserve_kbytes will be safer than the current behavior since the hardcoded 3% of available memory reserve can shrink to something useless in the case where applications have grabbed all available memory. Risks * "bash: fork: Cannot allocate memory" The downside of the first patch-- which creates a tunable user reserve that is only used in overcommit 'never' mode--is that an admin can set it so low that a user may not be able to kill their process, even if they already have a shell prompt. Of course, a user can get in the same predicament with the current 3% reserve--they just have to launch processes until 3% becomes negligible. * root-cant-log-in problem The second patch, adding the tunable rootuser_reserve_pages, allows the admin to shoot themselves in the foot by setting it too small. They can easily get the system into a state where root-can't-log-in. However, the new admin_reserve_kbytes will be safer than the current behavior since the hardcoded 3% of available memory reserve can shrink to something useless in the case where applications have grabbed all available memory. Alternatives * Memory cgroups provide a more flexible way to limit application memory. Not everyone wants to set up cgroups or deal with their overhead. * We could create a fourth overcommit mode which provides smaller reserves. The size of useful reserves may be drastically different depending on the whether the system is embedded or enterprise. * Force users to initialize all of their memory or use calloc. Some users don't want/expect the system to overcommit when they malloc. Overcommit 'never' mode is for this scenario, and it should work well. The new user and admin reserve tunables are simple to use, with low overhead compared to cgroups. The patches preserve current behavior where 3% of memory is less than 128MB, except that the admin reserve doesn't shrink to an unusable size under pressure. The code allows admins to tune for embedded and enterprise usage. FAQ * How is the root-cant-login problem addressed? What happens if admin_reserve_pages is set to 0? Root is free to shoot themselves in the foot by setting admin_reserve_kbytes too low. On x86_64, the minimum useful reserve is: 8MB for overcommit 'guess' 128MB for overcommit 'never' admin_reserve_pages defaults to min(3% free memory, 8MB) So, anyone switching to 'never' mode needs to adjust admin_reserve_pages. * How do you calculate a minimum useful reserve? A user or the admin needs enough memory to login and perform recovery operations, which includes, at a minimum: sshd or login + bash (or some other shell) + top (or ps, kill, etc.) For overcommit 'guess', we can sum resident set sizes (RSS) because we only need enough memory to handle what the recovery programs will typically use. On x86_64 this is about 8MB. For overcommit 'never', we can take the max of their virtual sizes (VSZ) and add the sum of their RSS. We use VSZ instead of RSS because mode forces us to ensure we can fulfill all of the requested memory allocations-- even if the programs only use a fraction of what they ask for. On x86_64 this is about 128MB. When swap is enabled, reserves are useful even when they are as small as 10MB, regardless of overcommit mode. When both swap and overcommit are disabled, then the admin should tune the reserves higher to be absolutley safe. Over 230MB each was safest in my testing. * What happens if user_reserve_pages is set to 0? Note, this only affects overcomitt 'never' mode. Then a user will be able to allocate all available memory minus admin_reserve_kbytes. However, they will easily see a message such as: "bash: fork: Cannot allocate memory" And they won't be able to recover/kill their application. The admin should be able to recover the system if admin_reserve_kbytes is set appropriately. * What's the difference between overcommit 'guess' and 'never'? "Guess" allows an allocation if there are enough free + reclaimable pages. It has a hardcoded 3% of free pages reserved for root. "Never" allows an allocation if there is enough swap + a configurable percentage (default is 50) of physical RAM. It has a hardcoded 3% of free pages reserved for root, like "Guess" mode. It also has a hardcoded 3% of the current process size reserved for additional applications. * Why is overcommit 'guess' not suitable even when an app eventually writes to every page? It takes free pages, file pages, available swap pages, reclaimable slab pages into consideration. In other words, these are all pages available, then why isn't overcommit suitable? Because it only looks at the present state of the system. It does not take into account the memory that other applications have malloced, but haven't initialized yet. It overcommits the system. Test Summary There was little change in behavior in the default overcommit 'guess' mode with swap enabled before and after the patch. This was expected. Systems run most predictably (i.e. no oom kills) in overcommit 'never' mode with swap enabled. This also allowed the most memory to be allocated to a user application. Overcommit 'guess' mode without swap is a bad idea. It is easy to crash the system. None of the other tested combinations crashed. This matches my experience on the Roadrunner supercomputer. Without the tunable user reserve, a system in overcommit 'never' mode and without swap does not allow the admin to recover, although the admin can. With the new tunable reserves, a system in overcommit 'never' mode and without swap can be configured to: 1. maximize user-allocatable memory, running close to the edge of recoverability 2. maximize recoverability, sacrificing allocatable memory to ensure that a user cannot take down a system Test Description Fedora 18 VM - 4 x86_64 cores, 5725MB RAM, 4GB Swap System is booted into multiuser console mode, with unnecessary services turned off. Caches were dropped before each test. Hogs are user memtester processes that attempt to allocate all free memory as reported by /proc/meminfo In overcommit 'never' mode, memory_ratio=100 Test Results 3.9.0-rc1-mm1 Overcommit | Swap | Hogs | MB Got/Wanted | OOMs | User Recovery | Admin Recovery ---------- ---- ---- ------------- ---- ------------- -------------- guess yes 1 5432/5432 no yes yes guess yes 4 5444/5444 1 yes yes guess no 1 5302/5449 no yes yes guess no 4 - crash no no never yes 1 5460/5460 1 yes yes never yes 4 5460/5460 1 yes yes never no 1 5218/5432 no no yes never no 4 5203/5448 no no yes 3.9.0-rc1-mm1-tunablereserves User and Admin Recovery show their respective reserves, if applicable. Overcommit | Swap | Hogs | MB Got/Wanted | OOMs | User Recovery | Admin Recovery ---------- ---- ---- ------------- ---- ------------- -------------- guess yes 1 5419/5419 no - yes 8MB yes guess yes 4 5436/5436 1 - yes 8MB yes guess no 1 5440/5440 * - yes 8MB yes guess no 4 - crash - no 8MB no * process would successfully mlock, then the oom killer would pick it never yes 1 5446/5446 no 10MB yes 20MB yes never yes 4 5456/5456 no 10MB yes 20MB yes never no 1 5387/5429 no 128MB no 8MB barely never no 1 5323/5428 no 226MB barely 8MB barely never no 1 5323/5428 no 226MB barely 8MB barely never no 1 5359/5448 no 10MB no 10MB barely never no 1 5323/5428 no 0MB no 10MB barely never no 1 5332/5428 no 0MB no 50MB yes never no 1 5293/5429 no 0MB no 90MB yes never no 1 5001/5427 no 230MB yes 338MB yes never no 4* 4998/5424 no 230MB yes 338MB yes * more memtesters were launched, able to allocate approximately another 100MB Future Work - Test larger memory systems. - Test an embedded image. - Test other architectures. - Time malloc microbenchmarks. - Would it be useful to be able to set overcommit policy for each memory cgroup? - Some lines are slightly above 80 chars. Perhaps define a macro to convert between pages and kb? Other places in the kernel do this. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make init_user_reserve() static] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:10 +04:00
{
unsigned long free_kbytes;
mm: rename global_page_state to global_zone_page_state global_page_state is error prone as a recent bug report pointed out [1]. It only returns proper values for zone based counters as the enum it gets suggests. We already have global_node_page_state so let's rename global_page_state to global_zone_page_state to be more explicit here. All existing users seems to be correct: $ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c 2 NR_BOUNCE 2 NR_FREE_CMA_PAGES 11 NR_FREE_PAGES 1 NR_KERNEL_STACK_KB 1 NR_MLOCK 2 NR_PAGETABLE This patch shouldn't introduce any functional change. [1] http://lkml.kernel.org/r/201707260628.v6Q6SmaS030814@www262.sakura.ne.jp Link: http://lkml.kernel.org/r/20170801134256.5400-2-hannes@cmpxchg.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-07 02:23:36 +03:00
free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
mm: limit growth of 3% hardcoded other user reserve Add user_reserve_kbytes knob. Limit the growth of the memory reserved for other user processes to min(3% current process size, user_reserve_pages). Only about 8MB is necessary to enable recovery in the default mode, and only a few hundred MB are required even when overcommit is disabled. user_reserve_pages defaults to min(3% free pages, 128MB) I arrived at 128MB by taking the max VSZ of sshd, login, bash, and top ... then adding the RSS of each. This only affects OVERCOMMIT_NEVER mode. Background 1. user reserve __vm_enough_memory reserves a hardcoded 3% of the current process size for other applications when overcommit is disabled. This was done so that a user could recover if they launched a memory hogging process. Without the reserve, a user would easily run into a message such as: bash: fork: Cannot allocate memory 2. admin reserve Additionally, a hardcoded 3% of free memory is reserved for root in both overcommit 'guess' and 'never' modes. This was intended to prevent a scenario where root-cant-log-in and perform recovery operations. Note that this reserve shrinks, and doesn't guarantee a useful reserve. Motivation The two hardcoded memory reserves should be updated to account for current memory sizes. Also, the admin reserve would be more useful if it didn't shrink too much. When the current code was originally written, 1GB was considered "enterprise". Now the 3% reserve can grow to multiple GB on large memory systems, and it only needs to be a few hundred MB at most to enable a user or admin to recover a system with an unwanted memory hogging process. I've found that reducing these reserves is especially beneficial for a specific type of application load: * single application system * one or few processes (e.g. one per core) * allocating all available memory * not initializing every page immediately * long running I've run scientific clusters with this sort of load. A long running job sometimes failed many hours (weeks of CPU time) into a calculation. They weren't initializing all of their memory immediately, and they weren't using calloc, so I put systems into overcommit 'never' mode. These clusters run diskless and have no swap. However, with the current reserves, a user wishing to allocate as much memory as possible to one process may be prevented from using, for example, almost 2GB out of 32GB. The effect is less, but still significant when a user starts a job with one process per core. I have repeatedly seen a set of processes requesting the same amount of memory fail because one of them could not allocate the amount of memory a user would expect to be able to allocate. For example, Message Passing Interfce (MPI) processes, one per core. And it is similar for other parallel programming frameworks. Changing this reserve code will make the overcommit never mode more useful by allowing applications to allocate nearly all of the available memory. Also, the new admin_reserve_kbytes will be safer than the current behavior since the hardcoded 3% of available memory reserve can shrink to something useless in the case where applications have grabbed all available memory. Risks * "bash: fork: Cannot allocate memory" The downside of the first patch-- which creates a tunable user reserve that is only used in overcommit 'never' mode--is that an admin can set it so low that a user may not be able to kill their process, even if they already have a shell prompt. Of course, a user can get in the same predicament with the current 3% reserve--they just have to launch processes until 3% becomes negligible. * root-cant-log-in problem The second patch, adding the tunable rootuser_reserve_pages, allows the admin to shoot themselves in the foot by setting it too small. They can easily get the system into a state where root-can't-log-in. However, the new admin_reserve_kbytes will be safer than the current behavior since the hardcoded 3% of available memory reserve can shrink to something useless in the case where applications have grabbed all available memory. Alternatives * Memory cgroups provide a more flexible way to limit application memory. Not everyone wants to set up cgroups or deal with their overhead. * We could create a fourth overcommit mode which provides smaller reserves. The size of useful reserves may be drastically different depending on the whether the system is embedded or enterprise. * Force users to initialize all of their memory or use calloc. Some users don't want/expect the system to overcommit when they malloc. Overcommit 'never' mode is for this scenario, and it should work well. The new user and admin reserve tunables are simple to use, with low overhead compared to cgroups. The patches preserve current behavior where 3% of memory is less than 128MB, except that the admin reserve doesn't shrink to an unusable size under pressure. The code allows admins to tune for embedded and enterprise usage. FAQ * How is the root-cant-login problem addressed? What happens if admin_reserve_pages is set to 0? Root is free to shoot themselves in the foot by setting admin_reserve_kbytes too low. On x86_64, the minimum useful reserve is: 8MB for overcommit 'guess' 128MB for overcommit 'never' admin_reserve_pages defaults to min(3% free memory, 8MB) So, anyone switching to 'never' mode needs to adjust admin_reserve_pages. * How do you calculate a minimum useful reserve? A user or the admin needs enough memory to login and perform recovery operations, which includes, at a minimum: sshd or login + bash (or some other shell) + top (or ps, kill, etc.) For overcommit 'guess', we can sum resident set sizes (RSS) because we only need enough memory to handle what the recovery programs will typically use. On x86_64 this is about 8MB. For overcommit 'never', we can take the max of their virtual sizes (VSZ) and add the sum of their RSS. We use VSZ instead of RSS because mode forces us to ensure we can fulfill all of the requested memory allocations-- even if the programs only use a fraction of what they ask for. On x86_64 this is about 128MB. When swap is enabled, reserves are useful even when they are as small as 10MB, regardless of overcommit mode. When both swap and overcommit are disabled, then the admin should tune the reserves higher to be absolutley safe. Over 230MB each was safest in my testing. * What happens if user_reserve_pages is set to 0? Note, this only affects overcomitt 'never' mode. Then a user will be able to allocate all available memory minus admin_reserve_kbytes. However, they will easily see a message such as: "bash: fork: Cannot allocate memory" And they won't be able to recover/kill their application. The admin should be able to recover the system if admin_reserve_kbytes is set appropriately. * What's the difference between overcommit 'guess' and 'never'? "Guess" allows an allocation if there are enough free + reclaimable pages. It has a hardcoded 3% of free pages reserved for root. "Never" allows an allocation if there is enough swap + a configurable percentage (default is 50) of physical RAM. It has a hardcoded 3% of free pages reserved for root, like "Guess" mode. It also has a hardcoded 3% of the current process size reserved for additional applications. * Why is overcommit 'guess' not suitable even when an app eventually writes to every page? It takes free pages, file pages, available swap pages, reclaimable slab pages into consideration. In other words, these are all pages available, then why isn't overcommit suitable? Because it only looks at the present state of the system. It does not take into account the memory that other applications have malloced, but haven't initialized yet. It overcommits the system. Test Summary There was little change in behavior in the default overcommit 'guess' mode with swap enabled before and after the patch. This was expected. Systems run most predictably (i.e. no oom kills) in overcommit 'never' mode with swap enabled. This also allowed the most memory to be allocated to a user application. Overcommit 'guess' mode without swap is a bad idea. It is easy to crash the system. None of the other tested combinations crashed. This matches my experience on the Roadrunner supercomputer. Without the tunable user reserve, a system in overcommit 'never' mode and without swap does not allow the admin to recover, although the admin can. With the new tunable reserves, a system in overcommit 'never' mode and without swap can be configured to: 1. maximize user-allocatable memory, running close to the edge of recoverability 2. maximize recoverability, sacrificing allocatable memory to ensure that a user cannot take down a system Test Description Fedora 18 VM - 4 x86_64 cores, 5725MB RAM, 4GB Swap System is booted into multiuser console mode, with unnecessary services turned off. Caches were dropped before each test. Hogs are user memtester processes that attempt to allocate all free memory as reported by /proc/meminfo In overcommit 'never' mode, memory_ratio=100 Test Results 3.9.0-rc1-mm1 Overcommit | Swap | Hogs | MB Got/Wanted | OOMs | User Recovery | Admin Recovery ---------- ---- ---- ------------- ---- ------------- -------------- guess yes 1 5432/5432 no yes yes guess yes 4 5444/5444 1 yes yes guess no 1 5302/5449 no yes yes guess no 4 - crash no no never yes 1 5460/5460 1 yes yes never yes 4 5460/5460 1 yes yes never no 1 5218/5432 no no yes never no 4 5203/5448 no no yes 3.9.0-rc1-mm1-tunablereserves User and Admin Recovery show their respective reserves, if applicable. Overcommit | Swap | Hogs | MB Got/Wanted | OOMs | User Recovery | Admin Recovery ---------- ---- ---- ------------- ---- ------------- -------------- guess yes 1 5419/5419 no - yes 8MB yes guess yes 4 5436/5436 1 - yes 8MB yes guess no 1 5440/5440 * - yes 8MB yes guess no 4 - crash - no 8MB no * process would successfully mlock, then the oom killer would pick it never yes 1 5446/5446 no 10MB yes 20MB yes never yes 4 5456/5456 no 10MB yes 20MB yes never no 1 5387/5429 no 128MB no 8MB barely never no 1 5323/5428 no 226MB barely 8MB barely never no 1 5323/5428 no 226MB barely 8MB barely never no 1 5359/5448 no 10MB no 10MB barely never no 1 5323/5428 no 0MB no 10MB barely never no 1 5332/5428 no 0MB no 50MB yes never no 1 5293/5429 no 0MB no 90MB yes never no 1 5001/5427 no 230MB yes 338MB yes never no 4* 4998/5424 no 230MB yes 338MB yes * more memtesters were launched, able to allocate approximately another 100MB Future Work - Test larger memory systems. - Test an embedded image. - Test other architectures. - Time malloc microbenchmarks. - Would it be useful to be able to set overcommit policy for each memory cgroup? - Some lines are slightly above 80 chars. Perhaps define a macro to convert between pages and kb? Other places in the kernel do this. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make init_user_reserve() static] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:10 +04:00
sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
return 0;
}
mm: audit/fix non-modular users of module_init in core code Code that is obj-y (always built-in) or dependent on a bool Kconfig (built-in or absent) can never be modular. So using module_init as an alias for __initcall can be somewhat misleading. Fix these up now, so that we can relocate module_init from init.h into module.h in the future. If we don't do this, we'd have to add module.h to obviously non-modular code, and that would be a worse thing. The audit targets the following module_init users for change: mm/ksm.c bool KSM mm/mmap.c bool MMU mm/huge_memory.c bool TRANSPARENT_HUGEPAGE mm/mmu_notifier.c bool MMU_NOTIFIER Note that direct use of __initcall is discouraged, vs. one of the priority categorized subgroups. As __initcall gets mapped onto device_initcall, our use of subsys_initcall (which makes sense for these files) will thus change this registration from level 6-device to level 4-subsys (i.e. slightly earlier). However no observable impact of that difference has been observed during testing. One might think that core_initcall (l2) or postcore_initcall (l3) would be more appropriate for anything in mm/ but if we look at some actual init functions themselves, we see things like: mm/huge_memory.c --> hugepage_init --> hugepage_init_sysfs mm/mmap.c --> init_user_reserve --> sysctl_user_reserve_kbytes mm/ksm.c --> ksm_init --> sysfs_create_group and hence the choice of subsys_initcall (l4) seems reasonable, and at the same time minimizes the risk of changing the priority too drastically all at once. We can adjust further in the future. Also, several instances of missing ";" at EOL are fixed. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-24 03:53:30 +04:00
subsys_initcall(init_user_reserve);
mm: replace hardcoded 3% with admin_reserve_pages knob Add an admin_reserve_kbytes knob to allow admins to change the hardcoded memory reserve to something other than 3%, which may be multiple gigabytes on large memory systems. Only about 8MB is necessary to enable recovery in the default mode, and only a few hundred MB are required even when overcommit is disabled. This affects OVERCOMMIT_GUESS and OVERCOMMIT_NEVER. admin_reserve_kbytes is initialized to min(3% free pages, 8MB) I arrived at 8MB by summing the RSS of sshd or login, bash, and top. Please see first patch in this series for full background, motivation, testing, and full changelog. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make init_admin_reserve() static] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:11 +04:00
/*
* Initialise sysctl_admin_reserve_kbytes.
*
* The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
* to log in and kill a memory hogging process.
*
* Systems with more than 256MB will reserve 8MB, enough to recover
* with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
* only reserve 3% of free pages by default.
*/
mm: reinititalise user and admin reserves if memory is added or removed Alter the admin and user reserves of the previous patches in this series when memory is added or removed. If memory is added and the reserves have been eliminated or increased above the default max, then we'll trust the admin. If memory is removed and there isn't enough free memory, then we need to reset the reserves. Otherwise keep the reserve set by the admin. The reserve reset code is the same as the reserve initialization code. I tested hot addition and removal by triggering it via sysfs. The reserves shrunk when they were set high and memory was removed. They were reset higher when memory was added again. [akpm@linux-foundation.org: use register_hotmemory_notifier()] [akpm@linux-foundation.org: init_user_reserve() and init_admin_reserve can no longer be __meminit] [fengguang.wu@intel.com: make init_reserve_notifier() static] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:12 +04:00
static int init_admin_reserve(void)
mm: replace hardcoded 3% with admin_reserve_pages knob Add an admin_reserve_kbytes knob to allow admins to change the hardcoded memory reserve to something other than 3%, which may be multiple gigabytes on large memory systems. Only about 8MB is necessary to enable recovery in the default mode, and only a few hundred MB are required even when overcommit is disabled. This affects OVERCOMMIT_GUESS and OVERCOMMIT_NEVER. admin_reserve_kbytes is initialized to min(3% free pages, 8MB) I arrived at 8MB by summing the RSS of sshd or login, bash, and top. Please see first patch in this series for full background, motivation, testing, and full changelog. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make init_admin_reserve() static] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:11 +04:00
{
unsigned long free_kbytes;
mm: rename global_page_state to global_zone_page_state global_page_state is error prone as a recent bug report pointed out [1]. It only returns proper values for zone based counters as the enum it gets suggests. We already have global_node_page_state so let's rename global_page_state to global_zone_page_state to be more explicit here. All existing users seems to be correct: $ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c 2 NR_BOUNCE 2 NR_FREE_CMA_PAGES 11 NR_FREE_PAGES 1 NR_KERNEL_STACK_KB 1 NR_MLOCK 2 NR_PAGETABLE This patch shouldn't introduce any functional change. [1] http://lkml.kernel.org/r/201707260628.v6Q6SmaS030814@www262.sakura.ne.jp Link: http://lkml.kernel.org/r/20170801134256.5400-2-hannes@cmpxchg.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-07 02:23:36 +03:00
free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
mm: replace hardcoded 3% with admin_reserve_pages knob Add an admin_reserve_kbytes knob to allow admins to change the hardcoded memory reserve to something other than 3%, which may be multiple gigabytes on large memory systems. Only about 8MB is necessary to enable recovery in the default mode, and only a few hundred MB are required even when overcommit is disabled. This affects OVERCOMMIT_GUESS and OVERCOMMIT_NEVER. admin_reserve_kbytes is initialized to min(3% free pages, 8MB) I arrived at 8MB by summing the RSS of sshd or login, bash, and top. Please see first patch in this series for full background, motivation, testing, and full changelog. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make init_admin_reserve() static] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:11 +04:00
sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
return 0;
}
mm: audit/fix non-modular users of module_init in core code Code that is obj-y (always built-in) or dependent on a bool Kconfig (built-in or absent) can never be modular. So using module_init as an alias for __initcall can be somewhat misleading. Fix these up now, so that we can relocate module_init from init.h into module.h in the future. If we don't do this, we'd have to add module.h to obviously non-modular code, and that would be a worse thing. The audit targets the following module_init users for change: mm/ksm.c bool KSM mm/mmap.c bool MMU mm/huge_memory.c bool TRANSPARENT_HUGEPAGE mm/mmu_notifier.c bool MMU_NOTIFIER Note that direct use of __initcall is discouraged, vs. one of the priority categorized subgroups. As __initcall gets mapped onto device_initcall, our use of subsys_initcall (which makes sense for these files) will thus change this registration from level 6-device to level 4-subsys (i.e. slightly earlier). However no observable impact of that difference has been observed during testing. One might think that core_initcall (l2) or postcore_initcall (l3) would be more appropriate for anything in mm/ but if we look at some actual init functions themselves, we see things like: mm/huge_memory.c --> hugepage_init --> hugepage_init_sysfs mm/mmap.c --> init_user_reserve --> sysctl_user_reserve_kbytes mm/ksm.c --> ksm_init --> sysfs_create_group and hence the choice of subsys_initcall (l4) seems reasonable, and at the same time minimizes the risk of changing the priority too drastically all at once. We can adjust further in the future. Also, several instances of missing ";" at EOL are fixed. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-24 03:53:30 +04:00
subsys_initcall(init_admin_reserve);
mm: reinititalise user and admin reserves if memory is added or removed Alter the admin and user reserves of the previous patches in this series when memory is added or removed. If memory is added and the reserves have been eliminated or increased above the default max, then we'll trust the admin. If memory is removed and there isn't enough free memory, then we need to reset the reserves. Otherwise keep the reserve set by the admin. The reserve reset code is the same as the reserve initialization code. I tested hot addition and removal by triggering it via sysfs. The reserves shrunk when they were set high and memory was removed. They were reset higher when memory was added again. [akpm@linux-foundation.org: use register_hotmemory_notifier()] [akpm@linux-foundation.org: init_user_reserve() and init_admin_reserve can no longer be __meminit] [fengguang.wu@intel.com: make init_reserve_notifier() static] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:12 +04:00
/*
* Reinititalise user and admin reserves if memory is added or removed.
*
* The default user reserve max is 128MB, and the default max for the
* admin reserve is 8MB. These are usually, but not always, enough to
* enable recovery from a memory hogging process using login/sshd, a shell,
* and tools like top. It may make sense to increase or even disable the
* reserve depending on the existence of swap or variations in the recovery
* tools. So, the admin may have changed them.
*
* If memory is added and the reserves have been eliminated or increased above
* the default max, then we'll trust the admin.
*
* If memory is removed and there isn't enough free memory, then we
* need to reset the reserves.
*
* Otherwise keep the reserve set by the admin.
*/
static int reserve_mem_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
unsigned long tmp, free_kbytes;
switch (action) {
case MEM_ONLINE:
/* Default max is 128MB. Leave alone if modified by operator. */
tmp = sysctl_user_reserve_kbytes;
if (0 < tmp && tmp < (1UL << 17))
init_user_reserve();
/* Default max is 8MB. Leave alone if modified by operator. */
tmp = sysctl_admin_reserve_kbytes;
if (0 < tmp && tmp < (1UL << 13))
init_admin_reserve();
break;
case MEM_OFFLINE:
mm: rename global_page_state to global_zone_page_state global_page_state is error prone as a recent bug report pointed out [1]. It only returns proper values for zone based counters as the enum it gets suggests. We already have global_node_page_state so let's rename global_page_state to global_zone_page_state to be more explicit here. All existing users seems to be correct: $ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c 2 NR_BOUNCE 2 NR_FREE_CMA_PAGES 11 NR_FREE_PAGES 1 NR_KERNEL_STACK_KB 1 NR_MLOCK 2 NR_PAGETABLE This patch shouldn't introduce any functional change. [1] http://lkml.kernel.org/r/201707260628.v6Q6SmaS030814@www262.sakura.ne.jp Link: http://lkml.kernel.org/r/20170801134256.5400-2-hannes@cmpxchg.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-07 02:23:36 +03:00
free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
mm: reinititalise user and admin reserves if memory is added or removed Alter the admin and user reserves of the previous patches in this series when memory is added or removed. If memory is added and the reserves have been eliminated or increased above the default max, then we'll trust the admin. If memory is removed and there isn't enough free memory, then we need to reset the reserves. Otherwise keep the reserve set by the admin. The reserve reset code is the same as the reserve initialization code. I tested hot addition and removal by triggering it via sysfs. The reserves shrunk when they were set high and memory was removed. They were reset higher when memory was added again. [akpm@linux-foundation.org: use register_hotmemory_notifier()] [akpm@linux-foundation.org: init_user_reserve() and init_admin_reserve can no longer be __meminit] [fengguang.wu@intel.com: make init_reserve_notifier() static] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:12 +04:00
if (sysctl_user_reserve_kbytes > free_kbytes) {
init_user_reserve();
pr_info("vm.user_reserve_kbytes reset to %lu\n",
sysctl_user_reserve_kbytes);
}
if (sysctl_admin_reserve_kbytes > free_kbytes) {
init_admin_reserve();
pr_info("vm.admin_reserve_kbytes reset to %lu\n",
sysctl_admin_reserve_kbytes);
}
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block reserve_mem_nb = {
.notifier_call = reserve_mem_notifier,
};
static int __meminit init_reserve_notifier(void)
{
if (register_hotmemory_notifier(&reserve_mem_nb))
mm: convert some level-less printks to pr_* printk is meant to be used with an associated log level. There are some instances of printk scattered around the mm code where the log level is missing. Add a log level and adhere to suggestions by scripts/checkpatch.pl by moving to the pr_* macros. Also add the typical pr_fmt definition so that print statements can be easily traced back to the modules where they occur, correlated one with another, etc. This will require the removal of some (now redundant) prefixes on a few print statements. Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-07 01:38:30 +04:00
pr_err("Failed registering memory add/remove notifier for admin reserve\n");
mm: reinititalise user and admin reserves if memory is added or removed Alter the admin and user reserves of the previous patches in this series when memory is added or removed. If memory is added and the reserves have been eliminated or increased above the default max, then we'll trust the admin. If memory is removed and there isn't enough free memory, then we need to reset the reserves. Otherwise keep the reserve set by the admin. The reserve reset code is the same as the reserve initialization code. I tested hot addition and removal by triggering it via sysfs. The reserves shrunk when they were set high and memory was removed. They were reset higher when memory was added again. [akpm@linux-foundation.org: use register_hotmemory_notifier()] [akpm@linux-foundation.org: init_user_reserve() and init_admin_reserve can no longer be __meminit] [fengguang.wu@intel.com: make init_reserve_notifier() static] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew Shewmaker <agshew@gmail.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 02:08:12 +04:00
return 0;
}
mm: audit/fix non-modular users of module_init in core code Code that is obj-y (always built-in) or dependent on a bool Kconfig (built-in or absent) can never be modular. So using module_init as an alias for __initcall can be somewhat misleading. Fix these up now, so that we can relocate module_init from init.h into module.h in the future. If we don't do this, we'd have to add module.h to obviously non-modular code, and that would be a worse thing. The audit targets the following module_init users for change: mm/ksm.c bool KSM mm/mmap.c bool MMU mm/huge_memory.c bool TRANSPARENT_HUGEPAGE mm/mmu_notifier.c bool MMU_NOTIFIER Note that direct use of __initcall is discouraged, vs. one of the priority categorized subgroups. As __initcall gets mapped onto device_initcall, our use of subsys_initcall (which makes sense for these files) will thus change this registration from level 6-device to level 4-subsys (i.e. slightly earlier). However no observable impact of that difference has been observed during testing. One might think that core_initcall (l2) or postcore_initcall (l3) would be more appropriate for anything in mm/ but if we look at some actual init functions themselves, we see things like: mm/huge_memory.c --> hugepage_init --> hugepage_init_sysfs mm/mmap.c --> init_user_reserve --> sysctl_user_reserve_kbytes mm/ksm.c --> ksm_init --> sysfs_create_group and hence the choice of subsys_initcall (l4) seems reasonable, and at the same time minimizes the risk of changing the priority too drastically all at once. We can adjust further in the future. Also, several instances of missing ";" at EOL are fixed. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-24 03:53:30 +04:00
subsys_initcall(init_reserve_notifier);
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