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This sysctl has the very unusual behaviour of not allowing any user (even
CAP_SYS_ADMIN) to reduce the restriction setting, meaning that if you were
to set this sysctl to a more restrictive option in the host pidns you
would need to reboot your machine in order to reset it.
The justification given in [1] is that this is a security feature and thus
it should not be possible to disable. Aside from the fact that we have
plenty of security-related sysctls that can be disabled after being
enabled (fs.protected_symlinks for instance), the protection provided by
the sysctl is to stop users from being able to create a binary and then
execute it. A user with CAP_SYS_ADMIN can trivially do this without
memfd_create(2):
% cat mount-memfd.c
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/mount.h>
#define SHELLCODE "#!/bin/echo this file was executed from this totally private tmpfs:"
int main(void)
{
int fsfd = fsopen("tmpfs", FSOPEN_CLOEXEC);
assert(fsfd >= 0);
assert(!fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 2));
int dfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);
assert(dfd >= 0);
int execfd = openat(dfd, "exe", O_CREAT | O_RDWR | O_CLOEXEC, 0782);
assert(execfd >= 0);
assert(write(execfd, SHELLCODE, strlen(SHELLCODE)) == strlen(SHELLCODE));
assert(!close(execfd));
char *execpath = NULL;
char *argv[] = { "bad-exe", NULL }, *envp[] = { NULL };
execfd = openat(dfd, "exe", O_PATH | O_CLOEXEC);
assert(execfd >= 0);
assert(asprintf(&execpath, "/proc/self/fd/%d", execfd) > 0);
assert(!execve(execpath, argv, envp));
}
% ./mount-memfd
this file was executed from this totally private tmpfs: /proc/self/fd/5
%
Given that it is possible for CAP_SYS_ADMIN users to create executable
binaries without memfd_create(2) and without touching the host filesystem
(not to mention the many other things a CAP_SYS_ADMIN process would be
able to do that would be equivalent or worse), it seems strange to cause a
fair amount of headache to admins when there doesn't appear to be an
actual security benefit to blocking this. There appear to be concerns
about confused-deputy-esque attacks[2] but a confused deputy that can
write to arbitrary sysctls is a bigger security issue than executable
memfds.
/* New API */
The primary requirement from the original author appears to be more based
on the need to be able to restrict an entire system in a hierarchical
manner[3], such that child namespaces cannot re-enable executable memfds.
So, implement that behaviour explicitly -- the vm.memfd_noexec scope is
evaluated up the pidns tree to &init_pid_ns and you have the most
restrictive value applied to you. The new lower limit you can set
vm.memfd_noexec is whatever limit applies to your parent.
Note that a pidns will inherit a copy of the parent pidns's effective
vm.memfd_noexec setting at unshare() time. This matches the existing
behaviour, and it also ensures that a pidns will never have its
vm.memfd_noexec setting *lowered* behind its back (but it will be raised
if the parent raises theirs).
/* Backwards Compatibility */
As the previous version of the sysctl didn't allow you to lower the
setting at all, there are no backwards compatibility issues with this
aspect of the change.
However it should be noted that now that the setting is completely
hierarchical. Previously, a cloned pidns would just copy the current
pidns setting, meaning that if the parent's vm.memfd_noexec was changed it
wouldn't propoagate to existing pid namespaces. Now, the restriction
applies recursively. This is a uAPI change, however:
* The sysctl is very new, having been merged in 6.3.
* Several aspects of the sysctl were broken up until this patchset and
the other patchset by Jeff Xu last month.
And thus it seems incredibly unlikely that any real users would run into
this issue. In the worst case, if this causes userspace isues we could
make it so that modifying the setting follows the hierarchical rules but
the restriction checking uses the cached copy.
[1]: https://lore.kernel.org/CABi2SkWnAgHK1i6iqSqPMYuNEhtHBkO8jUuCvmG3RmUB5TKHJw@mail.gmail.com/
[2]: https://lore.kernel.org/CALmYWFs_dNCzw_pW1yRAo4bGCPEtykroEQaowNULp7svwMLjOg@mail.gmail.com/
[3]: https://lore.kernel.org/CALmYWFuahdUF7cT4cm7_TGLqPanuHXJ-hVSfZt7vpTnc18DPrw@mail.gmail.com/
Link: https://lkml.kernel.org/r/20230814-memfd-vm-noexec-uapi-fixes-v2-4-7ff9e3e10ba6@cyphar.com
Fixes: 105ff5339f ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In order to incentivise userspace to switch to passing MFD_EXEC and
MFD_NOEXEC_SEAL, we need to provide a warning on each attempt to call
memfd_create() without the new flags. pr_warn_once() is not useful
because on most systems the one warning is burned up during the boot
process (on my system, systemd does this within the first second of boot)
and thus userspace will in practice never see the warnings to push them to
switch to the new flags.
The original patchset[1] used pr_warn_ratelimited(), however there were
concerns about the degree of spam in the kernel log[2,3]. The resulting
inability to detect every case was flagged as an issue at the time[4].
While we could come up with an alternative rate-limiting scheme such as
only outputting the message if vm.memfd_noexec has been modified, or only
outputting the message once for a given task, these alternatives have
downsides that don't make sense given how low-stakes a single kernel
warning message is. Switching to pr_info_ratelimited() instead should be
fine -- it's possible some monitoring tool will be unhappy with a stream
of warning-level messages but there's already plenty of info-level message
spam in dmesg.
[1]: https://lore.kernel.org/20221215001205.51969-4-jeffxu@google.com/
[2]: https://lore.kernel.org/202212161233.85C9783FB@keescook/
[3]: https://lore.kernel.org/Y5yS8wCnuYGLHMj4@x1n/
[4]: https://lore.kernel.org/f185bb42-b29c-977e-312e-3349eea15383@linuxfoundation.org/
Link: https://lkml.kernel.org/r/20230814-memfd-vm-noexec-uapi-fixes-v2-3-7ff9e3e10ba6@cyphar.com
Fixes: 105ff5339f ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Given the difficulty of auditing all of userspace to figure out whether
every memfd_create() user has switched to passing MFD_EXEC and
MFD_NOEXEC_SEAL flags, it seems far less distruptive to make it possible
for older programs that don't make use of executable memfds to run under
vm.memfd_noexec=2. Otherwise, a small dependency change can result in
spurious errors. For programs that don't use executable memfds, passing
MFD_NOEXEC_SEAL is functionally a no-op and thus having the same
In addition, every failure under vm.memfd_noexec=2 needs to print to the
kernel log so that userspace can figure out where the error came from.
The concerns about pr_warn_ratelimited() spam that caused the switch to
pr_warn_once()[1,2] do not apply to the vm.memfd_noexec=2 case.
This is a user-visible API change, but as it allows programs to do
something that would be blocked before, and the sysctl itself was broken
and recently released, it seems unlikely this will cause any issues.
[1]: https://lore.kernel.org/Y5yS8wCnuYGLHMj4@x1n/
[2]: https://lore.kernel.org/202212161233.85C9783FB@keescook/
Link: https://lkml.kernel.org/r/20230814-memfd-vm-noexec-uapi-fixes-v2-2-7ff9e3e10ba6@cyphar.com
Fixes: 105ff5339f ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit e774a7bc7f ("mm: zswap: remove page reclaim logic from
z3fold"), zpool and zpool_ops have been removed, so also remove the
corresponding comments.
Link: https://lkml.kernel.org/r/20230814221142.486548-1-xiujianfeng@huaweicloud.com
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We have get_pageblock_migratetype and get_pfnblock_migratetype to get
migratetype of page. get_pfnblock_migratetype accepts both page and pfn
from caller while get_pageblock_migratetype only accept page and get pfn
with page_to_pfn from page.
In case we already record pfn of page, we can simply call
get_pfnblock_migratetype to avoid a page_to_pfn.
Link: https://lkml.kernel.org/r/20230811115945.3423894-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Two minor cleanups for get pageblock migratetype".
This series contains two minor cleanups for get pageblock migratetype.
More details can be found in respective patches.
This patch (of 2):
get_pfnblock_flags_mask() just calls inline inner
__get_pfnblock_flags_mask without any extra work. Just opencode
__get_pfnblock_flags_mask in get_pfnblock_flags_mask and replace call to
__get_pfnblock_flags_mask with call to get_pfnblock_flags_mask to remove
unnecessary __get_pfnblock_flags_mask.
Link: https://lkml.kernel.org/r/20230811115945.3423894-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20230811115945.3423894-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Just remove the redundant parameter alloc_order from
reserve_highatomic_pageblock(). No functional modification involved.
Link: https://lkml.kernel.org/r/20230809073323.1065286-1-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch is based on the commit 5da226dbfce3("mm: skip CMA pages when
they are not available") which skips cma pages reclaim when they are not
eligible for the current allocation context. In mglru, such pages are
added to the tail of the immediate generation to maintain better LRU
order, which is unlike the case of conventional LRU where such pages are
directly added to the head of the LRU list(akin to adding to head of the
youngest generation in mglru).
No observable issue without this patch on MGLRU, but logically it make
sense to skip the CMA page reclaim when those pages can't be satisfied for
the current allocation context.
Link: https://lkml.kernel.org/r/1691568344-13475-1-git-send-email-quic_charante@quicinc.com
Fixes: ac35a49023 ("mm: multi-gen LRU: minimal implementation")
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Parameter pgdat is not used in fragmentation_score_wmark. Just remove it.
Link: https://lkml.kernel.org/r/20230809094910.3092446-1-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We get batch from pcp and just pass it to nr_pcp_free immediately. Get
batch from pcp inside nr_pcp_free to remove unnecessary parameter batch.
Link: https://lkml.kernel.org/r/20230809100754.3094517-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Two minor cleanups for pcp list in page_alloc".
There are two minor cleanups for pcp list in page_alloc. More details
can be found in respective patches.
This patch (of 2):
After commit fd56eef258 ("mm/page_alloc: simplify how many pages are
selected per pcp list during bulk free"), we will drain all pages in
selected pcp list. And we ensured passed count is < pcp->count. Then,
the search will finish before wrap-around and track of active PCP lists
range intended for wrap-around case is no longer needed.
Link: https://lkml.kernel.org/r/20230809100754.3094517-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20230809100754.3094517-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With memmap on memory, some architecture needs more details w.r.t altmap
such as base_pfn, end_pfn, etc to unmap vmemmap memory. Instead of
computing them again when we remove a memory block, embed vmem_altmap
details in struct memory_block if we are using memmap on memory block
feature.
[yangyingliang@huawei.com: fix error return code in add_memory_resource()]
Link: https://lkml.kernel.org/r/20230809081552.1351184-1-yangyingliang@huawei.com
Link: https://lkml.kernel.org/r/20230808091501.287660-7-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently, memmap_on_memory feature is only supported with memory block
sizes that result in vmemmap pages covering full page blocks. This is
because memory onlining/offlining code requires applicable ranges to be
pageblock-aligned, for example, to set the migratetypes properly.
This patch helps to lift that restriction by reserving more pages than
required for vmemmap space. This helps the start address to be page block
aligned with different memory block sizes. Using this facility implies
the kernel will be reserving some pages for every memoryblock. This
allows the memmap on memory feature to be widely useful with different
memory block size values.
For ex: with 64K page size and 256MiB memory block size, we require 4
pages to map vmemmap pages, To align things correctly we end up adding a
reserve of 28 pages. ie, for every 4096 pages 28 pages get reserved.
Link: https://lkml.kernel.org/r/20230808091501.287660-5-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Some architectures would want different restrictions. Hence add an
architecture-specific override.
The PMD_SIZE check is moved there.
Link: https://lkml.kernel.org/r/20230808091501.287660-4-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If not supported, fallback to not using memap on memmory. This avoids
the need for callers to do the fallback.
Link: https://lkml.kernel.org/r/20230808091501.287660-3-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Add support for memmap on memory feature on ppc64", v8.
This patch series update memmap on memory feature to fall back to
memmap allocation outside the memory block if the alignment rules are
not met. This makes the feature more useful on architectures like
ppc64 where alignment rules are different with 64K page size.
This patch (of 6):
Instead of adding menu entry with all supported architectures, add
mm/Kconfig variable and select the same from supported architectures.
No functional change in this patch.
Link: https://lkml.kernel.org/r/20230808091501.287660-1-aneesh.kumar@linux.ibm.com
Link: https://lkml.kernel.org/r/20230808091501.287660-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The check for root memcg will be done in wb_get_lookup(), so remove the
redundant one to simplify the code.
Link: https://lkml.kernel.org/r/20230808084431.1632934-1-alexjlzheng@tencent.com
Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit 0bb488498c ("mm: zswap: remove zswap_header"), the 'offset'
has been replaced by swpentry, update the comment for it, and also add
comment for 'objcg'.
Link: https://lkml.kernel.org/r/20230808062056.292950-1-xiujianfeng@huaweicloud.com
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It is better to not expose too many internal variables of memtest,
add a helper memtest_report_meminfo() to show memtest results.
Link: https://lkml.kernel.org/r/20230808033359.174986-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tomas Mudrunka <tomas.mudrunka@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It's more readable to use helper macro BITS_PER_LONG and BITS_PER_BYTE.
No functional change intended.
Link: https://lkml.kernel.org/r/20230807023528.325191-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It's more convenient to use helper macro llist_for_each_entry_safe().
No functional change intended.
Link: https://lkml.kernel.org/r/20230807114125.3440802-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Otherwise the kernel ends up with multiple copies:
$ nm vmlinux | grep dummy_vm_ops
ffffffff81e4ea00 d dummy_vm_ops.2
ffffffff81e11760 d dummy_vm_ops.254
ffffffff81e406e0 d dummy_vm_ops.4
ffffffff81e3c780 d dummy_vm_ops.7
While here prefix it with vma_.
Link: https://lkml.kernel.org/r/20230806231611.1395735-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
vma_prepare() is currently the central place where vmas are being locked
before vma_complete() applies changes to them. While this is convenient,
it also obscures vma locking and makes it harder to follow the locking
rules. Move vma locking out of vma_prepare() and take vma locks
explicitly at the locations where vmas are being modified. Move vma
locking and replace it with an assertion inside dup_anon_vma() to further
clarify the locking pattern inside vma_merge().
Link: https://lkml.kernel.org/r/20230804152724.3090321-7-surenb@google.com
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Suggested-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
While it's not strictly necessary to lock a newly created vma before
adding it into the vma tree (as long as no further changes are performed
to it), it seems like a good policy to lock it and prevent accidental
changes after it becomes visible to the page faults. Lock the vma before
adding it into the vma tree.
[akpm@linux-foundation.org: fix reject fixing in vma_link(), per Jann]
Link: https://lkml.kernel.org/r/20230804152724.3090321-6-surenb@google.com
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Implicit vma locking inside vm_flags_reset() and vm_flags_reset_once() is
not obvious and makes it hard to understand where vma locking is happening.
Also in some cases (like in dup_userfaultfd()) vma should be locked earlier
than vma_flags modification. To make locking more visible, change these
functions to assert that the vma write lock is taken and explicitly lock
the vma beforehand. Fix userfaultfd functions which should lock the vma
earlier.
Link: https://lkml.kernel.org/r/20230804152724.3090321-5-surenb@google.com
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vma write lock assertion always includes mmap write lock assertion and
additional vma lock checks when per-VMA locks are enabled. Replace
weaker mmap_assert_write_locked() assertions with stronger
vma_assert_write_locked() ones when we are operating on a vma which
is expected to be locked.
Link: https://lkml.kernel.org/r/20230804152724.3090321-4-surenb@google.com
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper macro K() to improve code readability. No functional
modification involved.
Link: https://lkml.kernel.org/r/20230804012559.2617515-8-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper macro K() to improve code readability. No functional
modification involved.
Link: https://lkml.kernel.org/r/20230804012559.2617515-7-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper macro K() to improve code readability. No functional
modification involved.
Link: https://lkml.kernel.org/r/20230804012559.2617515-6-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper macro K() to improve code readability. No functional
modification involved.
Link: https://lkml.kernel.org/r/20230804012559.2617515-5-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper macro K() to improve code readability. No functional
modification involved.
Link: https://lkml.kernel.org/r/20230804012559.2617515-4-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper macro K() to improve code readability. No functional
modification involved.
Link: https://lkml.kernel.org/r/20230804012559.2617515-3-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "cleanup with helper macro K()".
Use helper macro K() to improve code readability. No functional
modification involved. Remove redundant K() macro definition.
This patch (of 7):
Since commit eb8589b4f8 ("mm: move mem_init_print_info() to mm_init.c"),
the K() macro definition has been moved to mm/internal.h. Therefore, the
definitions in mm/memcontrol.c, mm/backing-dev.c and mm/oom_kill.c are
redundant. Drop redundant definitions.
[akpm@linux-foundation.org: oom_kill.c: remove "#undef K", per Kefeng]
Link: https://lkml.kernel.org/r/20230804012559.2617515-1-zhangpeng362@huawei.com
Link: https://lkml.kernel.org/r/20230804012559.2617515-2-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
For system with kernelcore=mirror enabled while no mirrored memory is
reported by efi. This could lead to kernel OOM during startup since all
memory beside zone DMA are in the movable zone and this prevents the
kernel to use it.
Zone DMA/DMA32 initialization is independent of mirrored memory and their
max pfn is set in zone_sizes_init(). Since kernel can fallback to zone
DMA/DMA32 if there is no memory in zone Normal, these zones are seen as
mirrored memory no mather their memory attributes are.
To solve this problem, disable kernelcore=mirror when there is no real
mirrored memory exists.
Link: https://lkml.kernel.org/r/20230802072328.2107981-1-mawupeng1@huawei.com
Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
Suggested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Levi Yun <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keep the same logic as update_pageblock_skip, only set skip if
no_set_skip_hint is false which is more reasonable.
Link: https://lkml.kernel.org/r/20230804110454.2935878-9-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove unnecessary return for void function
Link: https://lkml.kernel.org/r/20230804110454.2935878-8-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit e380bebe47 ("mm, compaction: keep migration source private to a
single compaction instance") moved update of async and sync
compact_cached_migrate_pfn from update_pageblock_skip to
update_cached_migrate but left the comment behind. Move the relevant
comment to correct this.
Link: https://lkml.kernel.org/r/20230804110454.2935878-6-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After 90ed667c03 ("Revert "Revert "mm/compaction: fix set skip in
fast_find_migrateblock"""), we remove skip set in fast_find_migrateblock.
Correct comment that fast_find_block is used to avoid isolation_suitable
check for pageblock returned from fast_find_migrateblock because
fast_find_migrateblock will mark found pageblock skipped.
Instead, comment that fast_find_block is used to avoid a redundant check
of fast found pageblock which is already checked skip flag inside
fast_find_migrateblock.
Link: https://lkml.kernel.org/r/20230804110454.2935878-5-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move migrate_pfn to page block end when block is marked skip to avoid
unnecessary scan retry of that block from upper caller. For example,
compact_zone may wrongly rescan skip page block with finish_pageblock
set as following:
1. cc->migrate point to the start of page block
2. compact_zone record last_migrated_pfn to cc->migrate
3. compact_zone->isolate_migratepages->isolate_migratepages_block
tries to scan the block. The low_pfn maybe moved forward to middle of
block because of free pages at beginning of block.
4. we find first lru page could be isolated but block was exclusive
marked skip.
5. abort isolate_migratepages_block and make cc->migrate_pfn point to
found lru page at middle of block.
6. compact_zone find cc->migrate_pfn and last_migrated_pfn are in the
same block and wrongly rescan the block with finish_pageblock set.
Link: https://lkml.kernel.org/r/20230804110454.2935878-4-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We record start pfn of last isolated page block with last_migrated_pfn. And
then:
1. We check if we mark the page block skip for exclusive access in
isolate_migratepages_block by test if next migrate pfn is still in last
isolated page block. If so, we will set finish_pageblock to do the
rescan.
2. We check if a full cc->order block is scanned by test if last scan
range passes the cc->order block boundary. If so, we flush the pages
were freed.
We treat cc->migrate_pfn before isolate_migratepages as the start pfn of
last isolated page range. However, we always align migrate_pfn to page
block or move to another page block in fast_find_migrateblock or in
linearly scan forward in isolate_migratepages before do page isolation in
isolate_migratepages_block.
Update last_migrated_pfn with pageblock_start_pfn(cc->migrate_pfn - 1)
after scan to correctly set start pfn of last isolated page range. To
avoid that:
1. Miss a rescan with finish_pageblock set as last_migrate_pfn does
not point to right pageblock and the migrate will not be in pageblock
of last_migrate_pfn as it should be.
2. Wrongly issue flush by test cc->order block boundary with wrong
last_migrate_pfn.
Link: https://lkml.kernel.org/r/20230804110454.2935878-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are no modules using mm_kobj, so do not export it.
Link: https://lkml.kernel.org/r/2023080436-algebra-cabana-417d@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Archs may need to do special things when flushing hugepage tlb, so use the
more applicable flush_hugetlb_tlb_range() instead of flush_tlb_range().
Link: https://lkml.kernel.org/r/20230801023145.17026-2-wangkefeng.wang@huawei.com
Fixes: 550a7d60bd ("mm, hugepages: add mremap() support for hugepage backed vma")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is no behavior change to remove "else continue" code at end of scan
loop. Just remove it to make code cleaner.
Link: https://lkml.kernel.org/r/20230803094901.2915942-5-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kemeng Shi <shikemeng@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The cursor is only used for page forward currently. We can simply move
page forward directly to remove unnecessary cursor.
Link: https://lkml.kernel.org/r/20230803094901.2915942-4-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kemeng Shi <shikemeng@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Merge the end_pfn boundary check for single page block forward and
multiple page blocks forward to avoid do twice boundary check for multiple
page blocks forward.
Link: https://lkml.kernel.org/r/20230803094901.2915942-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Fixes and cleanups to compaction", v2.
This series contains random fixes and cleanups to free page isolation in
compaction. This is based on another compact series[1]. More details can
be found in respective patches.
This patch (of 4):
We will set skip to page block of block_start_pfn, it's more reasonable to
set compact_cached_free_pfn to page block before the block_start_pfn.
Link: https://lkml.kernel.org/r/20230803094901.2915942-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20230803094901.2915942-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Kemeng Shi <shikemeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The correct function name is obj_cgroup_may_zswap(). Correct the comment.
Link: https://lkml.kernel.org/r/20230803120021.762279-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
