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commit 66eca1021a42856d6af2a9802c99e160278aed91 upstream.
It's expected that no page should be left in pcp_list after calling
zone_pcp_disable() in offline_pages(). Previously, it's observed that
offline_pages() gets stuck [1] due to some pages remaining in pcp_list.
Cause:
There is a race condition between drain_pages_zone() and __rmqueue_pcplist()
involving the pcp->count variable. See below scenario:
CPU0 CPU1
---------------- ---------------
spin_lock(&pcp->lock);
__rmqueue_pcplist() {
zone_pcp_disable() {
/* list is empty */
if (list_empty(list)) {
/* add pages to pcp_list */
alloced = rmqueue_bulk()
mutex_lock(&pcp_batch_high_lock)
...
__drain_all_pages() {
drain_pages_zone() {
/* read pcp->count, it's 0 here */
count = READ_ONCE(pcp->count)
/* 0 means nothing to drain */
/* update pcp->count */
pcp->count += alloced << order;
...
...
spin_unlock(&pcp->lock);
In this case, after calling zone_pcp_disable() though, there are still some
pages in pcp_list. And these pages in pcp_list are neither movable nor
isolated, offline_pages() gets stuck as a result.
Solution:
Expand the scope of the pcp->lock to also protect pcp->count in
drain_pages_zone(), to ensure no pages are left in the pcp list after
zone_pcp_disable()
[1] https://lore.kernel.org/linux-mm/6a07125f-e720-404c-b2f9-e55f3f166e85@fujitsu.com/
Link: https://lkml.kernel.org/r/20240723064428.1179519-1-lizhijian@fujitsu.com
Fixes: 4b23a68f9536 ("mm/page_alloc: protect PCP lists with a spinlock")
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Reported-by: Yao Xingtao <yaoxt.fnst@fujitsu.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 30d77b7eef019fa4422980806e8b7cdc8674493e upstream.
mem_cgroup_calculate_protection() is not stateless and should only be used
as part of a top-down tree traversal. shrink_one() traverses the per-node
memcg LRU instead of the root_mem_cgroup tree, and therefore it should not
call mem_cgroup_calculate_protection().
The existing misuse in shrink_one() can cause ineffective protection of
sub-trees that are grandchildren of root_mem_cgroup. Fix it by reusing
lru_gen_age_node(), which already traverses the root_mem_cgroup tree, to
calculate the protection.
Previously lru_gen_age_node() opportunistically skips the first pass,
i.e., when scan_control->priority is DEF_PRIORITY. On the second pass,
lruvec_is_sizable() uses appropriate scan_control->priority, set by
set_initial_priority() from lru_gen_shrink_node(), to decide whether a
memcg is too small to reclaim from.
Now lru_gen_age_node() unconditionally traverses the root_mem_cgroup tree.
So it should call set_initial_priority() upfront, to make sure
lruvec_is_sizable() uses appropriate scan_control->priority on the first
pass. Otherwise, lruvec_is_reclaimable() can return false negatives and
result in premature OOM kills when min_ttl_ms is used.
Link: https://lkml.kernel.org/r/20240712232956.1427127-1-yuzhao@google.com
Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: T.J. Mercier <tjmercier@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3f74e6bd3b84a8b6bb3cc51609c89e5b9d58eed7 upstream.
set_initial_priority() tries to jump-start global reclaim by estimating
the priority based on cold/hot LRU pages. The estimation does not account
for shrinker objects, and it cannot do so because their sizes can be in
different units other than page.
If shrinker objects are the majority, e.g., on TrueNAS SCALE 24.04.0 where
ZFS ARC can use almost all system memory, set_initial_priority() can
vastly underestimate how much memory ARC shrinker can evict and assign
extreme low values to scan_control->priority, resulting in overshoots of
shrinker objects.
To reproduce the problem, using TrueNAS SCALE 24.04.0 with 32GB DRAM, a
test ZFS pool and the following commands:
fio --name=mglru.file --numjobs=36 --ioengine=io_uring \
--directory=/root/test-zfs-pool/ --size=1024m --buffered=1 \
--rw=randread --random_distribution=random \
--time_based --runtime=1h &
for ((i = 0; i < 20; i++))
do
sleep 120
fio --name=mglru.anon --numjobs=16 --ioengine=mmap \
--filename=/dev/zero --size=1024m --fadvise_hint=0 \
--rw=randrw --random_distribution=random \
--time_based --runtime=1m
done
To fix the problem:
1. Cap scan_control->priority at or above DEF_PRIORITY/2, to prevent
the jump-start from being overly aggressive.
2. Account for the progress from mm_account_reclaimed_pages(), to
prevent kswapd_shrink_node() from raising the priority
unnecessarily.
Link: https://lkml.kernel.org/r/20240711191957.939105-2-yuzhao@google.com
Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: Alexander Motin <mav@ixsystems.com>
Cc: Wei Xu <weixugc@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7d6be67cfdd4a53cea7147313ca13c531e3a470f upstream.
Commit 2b5067a8143e ("mm: mmap_lock: add tracepoints around lock
acquisition") introduced TRACE_MMAP_LOCK_EVENT() macro using
preempt_disable() in order to let get_mm_memcg_path() return a percpu
buffer exclusively used by normal, softirq, irq and NMI contexts
respectively.
Commit 832b50725373 ("mm: mmap_lock: use local locks instead of disabling
preemption") replaced preempt_disable() with local_lock(&memcg_paths.lock)
based on an argument that preempt_disable() has to be avoided because
get_mm_memcg_path() might sleep if PREEMPT_RT=y.
But syzbot started reporting
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
and
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
messages, for local_lock() does not disable IRQ.
We could replace local_lock() with local_lock_irqsave() in order to
suppress these messages. But this patch instead replaces percpu buffers
with on-stack buffer, for the size of each buffer returned by
get_memcg_path_buf() is only 256 bytes which is tolerable for allocating
from current thread's kernel stack memory.
Link: https://lkml.kernel.org/r/ef22d289-eadb-4ed9-863b-fbc922b33d8d@I-love.SAKURA.ne.jp
Reported-by: syzbot <syzbot+40905bca570ae6784745@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=40905bca570ae6784745
Fixes: 832b50725373 ("mm: mmap_lock: use local locks instead of disabling preemption")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8b671fe1a879923ecfb72dda6caf01460dd885ef upstream.
evict_folios() uses a second pass to reclaim folios that have gone through
page writeback and become clean before it finishes the first pass, since
folio_rotate_reclaimable() cannot handle those folios due to the
isolation.
The second pass tries to avoid potential double counting by deducting
scan_control->nr_scanned. However, this can result in underflow of
nr_scanned, under a condition where shrink_folio_list() does not increment
nr_scanned, i.e., when folio_trylock() fails.
The underflow can cause the divisor, i.e., scale=scanned+reclaimed in
vmpressure_calc_level(), to become zero, resulting in the following crash:
[exception RIP: vmpressure_work_fn+101]
process_one_work at ffffffffa3313f2b
Since scan_control->nr_scanned has no established semantics, the potential
double counting has minimal risks. Therefore, fix the problem by not
deducting scan_control->nr_scanned in evict_folios().
Link: https://lkml.kernel.org/r/20240711191957.939105-1-yuzhao@google.com
Fixes: 359a5e1416ca ("mm: multi-gen LRU: retry folios written back while isolated")
Reported-by: Wei Xu <weixugc@google.com>
Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: Alexander Motin <mav@ixsystems.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 003af997c8a945493859dd1a2d015cc9387ff27a upstream.
When trying to allocate a hugepage with no reserved ones free, it may be
allowed in case a number of overcommit hugepages was configured (using
/proc/sys/vm/nr_overcommit_hugepages) and that number wasn't reached.
This allows for a behavior of having extra hugepages allocated
dynamically, if there're resources for it. Some sysadmins even prefer not
reserving any hugepages and setting a big number of overcommit hugepages.
But while attempting to allocate overcommit hugepages in a multi node
system (either NUMA or mempolicy/cpuset) said allocations might randomly
fail even when there're resources available for the allocation.
This happens due to allowed_mems_nr() only accounting for the number of
free hugepages in the nodes the current process belongs to and the surplus
hugepage allocation is done so it can be allocated in any node. In case
one or more of the requested surplus hugepages are allocated in a
different node, the whole allocation will fail due allowed_mems_nr()
returning a lower value.
So allocate surplus hugepages in one of the nodes the current process
belongs to.
Easy way to reproduce this issue is to use a 2+ NUMA nodes system:
# echo 0 >/proc/sys/vm/nr_hugepages
# echo 1 >/proc/sys/vm/nr_overcommit_hugepages
# numactl -m0 ./tools/testing/selftests/mm/map_hugetlb 2
Repeating the execution of map_hugetlb test application will eventually
fail when the hugepage ends up allocated in a different node.
[aris@ruivo.org: v2]
Link: https://lkml.kernel.org/r/20240701212343.GG844599@cathedrallabs.org
Link: https://lkml.kernel.org/r/20240621190050.mhxwb65zn37doegp@redhat.com
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vishal Moola <vishal.moola@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is a potential race between __update_and_free_hugetlb_folio() and
try_memory_failure_hugetlb():
CPU1 CPU2
__update_and_free_hugetlb_folio try_memory_failure_hugetlb
folio_test_hugetlb
-- It's still hugetlb folio.
folio_clear_hugetlb_hwpoison
spin_lock_irq(&hugetlb_lock);
__get_huge_page_for_hwpoison
folio_set_hugetlb_hwpoison
spin_unlock_irq(&hugetlb_lock);
spin_lock_irq(&hugetlb_lock);
__folio_clear_hugetlb(folio);
-- Hugetlb flag is cleared but too late.
spin_unlock_irq(&hugetlb_lock);
When the above race occurs, raw error page info will be leaked. Even
worse, raw error pages won't have hwpoisoned flag set and hit
pcplists/buddy. Fix this issue by deferring
folio_clear_hugetlb_hwpoison() until __folio_clear_hugetlb() is done. So
all raw error pages will have hwpoisoned flag set.
Link: https://lkml.kernel.org/r/20240708025127.107713-1-linmiaohe@huawei.com
Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The vmf->ptl in filemap_fault_recheck_pte_none() is still set from
handle_pte_fault(). But at the same time, we did a pte_unmap(vmf->pte).
After a pte_unmap(vmf->pte) unmap and rcu_read_unlock(), the page table
may be racily changed and vmf->ptl maybe fails to protect the actual page
table. Fix this by replacing pte_offset_map() with
pte_offset_map_nolock().
As David said, the PTL pointer might be stale so if we continue to use
it infilemap_fault_recheck_pte_none(), it might trigger UAF. Also, if
the PTL fails, the issue fixed by commit 58f327f2ce80 ("filemap: avoid
unnecessary major faults in filemap_fault()") might reappear.
Link: https://lkml.kernel.org/r/20240313012913.2395414-1-zhangpeng362@huawei.com
Fixes: 58f327f2ce80 ("filemap: avoid unnecessary major faults in filemap_fault()")
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Even on 6.10-rc6, I've been seeing elusive "Bad page state"s (often on
flags when freeing, yet the flags shown are not bad: PG_locked had been
set and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from
deferred_split_scan()'s folio_put(), and a variety of other BUG and WARN
symptoms implying double free by deferred split and large folio migration.
6.7 commit 9bcef5973e31 ("mm: memcg: fix split queue list crash when large
folio migration") was right to fix the memcg-dependent locking broken in
85ce2c517ade ("memcontrol: only transfer the memcg data for migration"),
but missed a subtlety of deferred_split_scan(): it moves folios to its own
local list to work on them without split_queue_lock, during which time
folio->_deferred_list is not empty, but even the "right" lock does nothing
to secure the folio and the list it is on.
Fortunately, deferred_split_scan() is careful to use folio_try_get(): so
folio_migrate_mapping() can avoid the race by folio_undo_large_rmappable()
while the old folio's reference count is temporarily frozen to 0 - adding
such a freeze in the !mapping case too (originally, folio lock and
unmapping and no swap cache left an anon folio unreachable, so no freezing
was needed there: but the deferred split queue offers a way to reach it).
Link: https://lkml.kernel.org/r/29c83d1a-11ca-b6c9-f92e-6ccb322af510@google.com
Fixes: 9bcef5973e31 ("mm: memcg: fix split queue list crash when large folio migration")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A kernel warning was reported when pinning folio in CMA memory when
launching SEV virtual machine. The splat looks like:
[ 464.325306] WARNING: CPU: 13 PID: 6734 at mm/gup.c:1313 __get_user_pages+0x423/0x520
[ 464.325464] CPU: 13 PID: 6734 Comm: qemu-kvm Kdump: loaded Not tainted 6.6.33+ #6
[ 464.325477] RIP: 0010:__get_user_pages+0x423/0x520
[ 464.325515] Call Trace:
[ 464.325520] <TASK>
[ 464.325523] ? __get_user_pages+0x423/0x520
[ 464.325528] ? __warn+0x81/0x130
[ 464.325536] ? __get_user_pages+0x423/0x520
[ 464.325541] ? report_bug+0x171/0x1a0
[ 464.325549] ? handle_bug+0x3c/0x70
[ 464.325554] ? exc_invalid_op+0x17/0x70
[ 464.325558] ? asm_exc_invalid_op+0x1a/0x20
[ 464.325567] ? __get_user_pages+0x423/0x520
[ 464.325575] __gup_longterm_locked+0x212/0x7a0
[ 464.325583] internal_get_user_pages_fast+0xfb/0x190
[ 464.325590] pin_user_pages_fast+0x47/0x60
[ 464.325598] sev_pin_memory+0xca/0x170 [kvm_amd]
[ 464.325616] sev_mem_enc_register_region+0x81/0x130 [kvm_amd]
Per the analysis done by yangge, when starting the SEV virtual machine, it
will call pin_user_pages_fast(..., FOLL_LONGTERM, ...) to pin the memory.
But the page is in CMA area, so fast GUP will fail then fallback to the
slow path due to the longterm pinnalbe check in try_grab_folio().
The slow path will try to pin the pages then migrate them out of CMA area.
But the slow path also uses try_grab_folio() to pin the page, it will
also fail due to the same check then the above warning is triggered.
In addition, the try_grab_folio() is supposed to be used in fast path and
it elevates folio refcount by using add ref unless zero. We are guaranteed
to have at least one stable reference in slow path, so the simple atomic add
could be used. The performance difference should be trivial, but the
misuse may be confusing and misleading.
Redefined try_grab_folio() to try_grab_folio_fast(), and try_grab_page()
to try_grab_folio(), and use them in the proper paths. This solves both
the abuse and the kernel warning.
The proper naming makes their usecase more clear and should prevent from
abusing in the future.
peterx said:
: The user will see the pin fails, for gpu-slow it further triggers the WARN
: right below that failure (as in the original report):
:
: folio = try_grab_folio(page, page_increm - 1,
: foll_flags);
: if (WARN_ON_ONCE(!folio)) { <------------------------ here
: /*
: * Release the 1st page ref if the
: * folio is problematic, fail hard.
: */
: gup_put_folio(page_folio(page), 1,
: foll_flags);
: ret = -EFAULT;
: goto out;
: }
[1] https://lore.kernel.org/linux-mm/1719478388-31917-1-git-send-email-yangge1116@126.com/
[shy828301@gmail.com: fix implicit declaration of function try_grab_folio_fast]
Link: https://lkml.kernel.org/r/CAHbLzkowMSso-4Nufc9hcMehQsK9PNz3OSu-+eniU-2Mm-xjhA@mail.gmail.com
Link: https://lkml.kernel.org/r/20240628191458.2605553-1-yang@os.amperecomputing.com
Fixes: 57edfcfd3419 ("mm/gup: accelerate thp gup even for "pages != NULL"")
Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
Reported-by: yangge <yangge1116@126.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org> [6.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
While investigating HVO for THPs [1], it turns out that speculative PFN
walkers like compaction can race with vmemmap modifications, e.g.,
CPU 1 (vmemmap modifier) CPU 2 (speculative PFN walker)
------------------------------- ------------------------------
Allocates an LRU folio page1
Sees page1
Frees page1
Allocates a hugeTLB folio page2
(page1 being a tail of page2)
Updates vmemmap mapping page1
get_page_unless_zero(page1)
Even though page1->_refcount is zero after HVO, get_page_unless_zero() can
still try to modify this read-only field, resulting in a crash.
An independent report [2] confirmed this race.
There are two discussed approaches to fix this race:
1. Make RO vmemmap RW so that get_page_unless_zero() can fail without
triggering a PF.
2. Use RCU to make sure get_page_unless_zero() either sees zero
page->_refcount through the old vmemmap or non-zero page->_refcount
through the new one.
The second approach is preferred here because:
1. It can prevent illegal modifications to struct page[] that has been
HVO'ed;
2. It can be generalized, in a way similar to ZERO_PAGE(), to fix
similar races in other places, e.g., arch_remove_memory() on x86
[3], which frees vmemmap mapping offlined struct page[].
While adding synchronize_rcu(), the goal is to be surgical, rather than
optimized. Specifically, calls to synchronize_rcu() on the error handling
paths can be coalesced, but it is not done for the sake of Simplicity:
noticeably, this fix removes ~50% more lines than it adds.
According to the hugetlb_optimize_vmemmap section in
Documentation/admin-guide/sysctl/vm.rst, enabling HVO makes allocating or
freeing hugeTLB pages "~2x slower than before". Having synchronize_rcu()
on top makes those operations even worse, and this also affects the user
interface /proc/sys/vm/nr_overcommit_hugepages.
This is *very* hard to trigger:
1. Most hugeTLB use cases I know of are static, i.e., reserved at
boot time, because allocating at runtime is not reliable at all.
2. On top of that, someone has to be very unlucky to get tripped
over above, because the race window is so small -- I wasn't able to
trigger it with a stress testing that does nothing but that (with
THPs though).
[1] https://lore.kernel.org/20240229183436.4110845-4-yuzhao@google.com/
[2] https://lore.kernel.org/917FFC7F-0615-44DD-90EE-9F85F8EA9974@linux.dev/
[3] https://lore.kernel.org/be130a96-a27e-4240-ad78-776802f57cad@redhat.com/
Link: https://lkml.kernel.org/r/20240627222705.2974207-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
syzbot detects that cachestat() is flushing stats, which can sleep, in its
RCU read section (see [1]). This is done in the workingset_test_recent()
step (which checks if the folio's eviction is recent).
Move the stat flushing step to before the RCU read section of cachestat,
and skip stat flushing during the recency check.
[1]: https://lore.kernel.org/cgroups/000000000000f71227061bdf97e0@google.com/
Link: https://lkml.kernel.org/r/20240627201737.3506959-1-nphamcs@gmail.com
Fixes: b00684722262 ("mm: workingset: move the stats flush into workingset_test_recent()")
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Reported-by: syzbot+b7f13b2d0cc156edf61a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/cgroups/000000000000f71227061bdf97e0@google.com/
Debugged-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: <stable@vger.kernel.org> [6.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In page_cache_ra_order(), the maximal order of the page cache to be
allocated shouldn't be larger than MAX_PAGECACHE_ORDER. Otherwise, it's
possible the large page cache can't be supported by xarray when the
corresponding xarray entry is split.
For example, HPAGE_PMD_ORDER is 13 on ARM64 when the base page size is
64KB. The PMD-sized page cache can't be supported by xarray.
Link: https://lkml.kernel.org/r/20240627003953.1262512-3-gshan@redhat.com
Fixes: 793917d997df ("mm/readahead: Add large folio readahead")
Signed-off-by: Gavin Shan <gshan@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Zhenyu Zhang <zhenyzha@redhat.com>
Cc: <stable@vger.kernel.org> [5.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON keeps the number of regions under max_nr_regions by skipping regions
split operations when doing so can make the number higher than the limit.
It works well for preventing violation of the limit. But, if somehow the
violation happens, it cannot recovery well depending on the situation. In
detail, if the real number of regions having different access pattern is
higher than the limit, the mechanism cannot reduce the number below the
limit. In such a case, the system could suffer from high monitoring
overhead of DAMON.
The violation can actually happen. For an example, the user could reduce
max_nr_regions while DAMON is running, to be lower than the current number
of regions. Fix the problem by repeating the merge operations with
increasing aggressiveness in kdamond_merge_regions() for the case, until
the limit is met.
[sj@kernel.org: increase regions merge aggressiveness while respecting min_nr_regions]
Link: https://lkml.kernel.org/r/20240626164753.46270-1-sj@kernel.org
[sj@kernel.org: ensure max threshold attempt for max_nr_regions violation]
Link: https://lkml.kernel.org/r/20240627163153.75969-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240624175814.89611-1-sj@kernel.org
Fixes: b9a6ac4e4ede ("mm/damon: adaptively adjust regions")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The problem is that there are systems where cpu_possible_mask has gaps
between set CPUs, for example SPARC. In this scenario addr_to_vb_xa()
hash function can return an index which accesses to not-possible and not
setup CPU area using per_cpu() macro. This results in an oops on SPARC.
A per-cpu vmap_block_queue is also used as hash table, incorrectly
assuming the cpu_possible_mask has no gaps. Fix it by adjusting an index
to a next possible CPU.
Link: https://lkml.kernel.org/r/20240626140330.89836-1-urezki@gmail.com
Fixes: 062eacf57ad9 ("mm: vmalloc: remove a global vmap_blocks xarray")
Reported-by: Nick Bowler <nbowler@draconx.ca>
Closes: https://lore.kernel.org/linux-kernel/ZntjIE6msJbF8zTa@MiWiFi-R3L-srv/T/
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The dirty throttling logic is interspersed with assumptions that dirty
limits in PAGE_SIZE units fit into 32-bit (so that various multiplications
fit into 64-bits). If limits end up being larger, we will hit overflows,
possible divisions by 0 etc. Fix these problems by never allowing so
large dirty limits as they have dubious practical value anyway. For
dirty_bytes / dirty_background_bytes interfaces we can just refuse to set
so large limits. For dirty_ratio / dirty_background_ratio it isn't so
simple as the dirty limit is computed from the amount of available memory
which can change due to memory hotplug etc. So when converting dirty
limits from ratios to numbers of pages, we just don't allow the result to
exceed UINT_MAX.
This is root-only triggerable problem which occurs when the operator
sets dirty limits to >16 TB.
Link: https://lkml.kernel.org/r/20240621144246.11148-2-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-By: Zach O'Keefe <zokeefe@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: Avoid possible overflows in dirty throttling".
Dirty throttling logic assumes dirty limits in page units fit into
32-bits. This patch series makes sure this is true (see patch 2/2 for
more details).
This patch (of 2):
This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78.
The commit is broken in several ways. Firstly, the removed (u64) cast
from the multiplication will introduce a multiplication overflow on 32-bit
archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the
default settings with 4GB of RAM will trigger this). Secondly, the
div64_u64() is unnecessarily expensive on 32-bit archs. We have
div64_ul() in case we want to be safe & cheap. Thirdly, if dirty
thresholds are larger than 1<<32 pages, then dirty balancing is going to
blow up in many other spectacular ways anyway so trying to fix one
possible overflow is just moot.
Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz
Fixes: 9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-By: Zach O'Keefe <zokeefe@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The requirement that the head page be passed to do_set_pmd() was added in
commit ef37b2ea08ac ("mm/memory: page_add_file_rmap() ->
folio_add_file_rmap_[pte|pmd]()") and prevents pmd-mapping in the
finish_fault() and filemap_map_pages() paths if the page to be inserted is
anything but the head page for an otherwise suitable vma and pmd-sized
page.
Matthew said:
: We're going to stop using PMDs to map large folios unless the fault is
: within the first 4KiB of the PMD. No idea how many workloads that
: affects, but it only needs to be backported as far as v6.8, so we may
: as well backport it.
Link: https://lkml.kernel.org/r/20240611153216.2794513-1-abrestic@rivosinc.com
Fixes: ef37b2ea08ac ("mm/memory: page_add_file_rmap() -> folio_add_file_rmap_[pte|pmd]()")
Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit 5d0a661d808f ("mm/page_alloc: use only one PCP list for
THP-sized allocations") no longer differentiates the migration type of
pages in THP-sized PCP list, it's possible that non-movable allocation
requests may get a CMA page from the list, in some cases, it's not
acceptable.
If a large number of CMA memory are configured in system (for example, the
CMA memory accounts for 50% of the system memory), starting a virtual
machine with device passthrough will get stuck. During starting the
virtual machine, it will call pin_user_pages_remote(..., FOLL_LONGTERM,
...) to pin memory. Normally if a page is present and in CMA area,
pin_user_pages_remote() will migrate the page from CMA area to non-CMA
area because of FOLL_LONGTERM flag. But if non-movable allocation
requests return CMA memory, migrate_longterm_unpinnable_pages() will
migrate a CMA page to another CMA page, which will fail to pass the check
in check_and_migrate_movable_pages() and cause migration endless.
Call trace:
pin_user_pages_remote
--__gup_longterm_locked // endless loops in this function
----_get_user_pages_locked
----check_and_migrate_movable_pages
------migrate_longterm_unpinnable_pages
--------alloc_migration_target
This problem will also have a negative impact on CMA itself. For example,
when CMA is borrowed by THP, and we need to reclaim it through cma_alloc()
or dma_alloc_coherent(), we must move those pages out to ensure CMA's
users can retrieve that contigous memory. Currently, CMA's memory is
occupied by non-movable pages, meaning we can't relocate them. As a
result, cma_alloc() is more likely to fail.
To fix the problem above, we add one PCP list for THP, which will not
introduce a new cacheline for struct per_cpu_pages. THP will have 2 PCP
lists, one PCP list is used by MOVABLE allocation, and the other PCP list
is used by UNMOVABLE allocation. MOVABLE allocation contains GPF_MOVABLE,
and UNMOVABLE allocation contains GFP_UNMOVABLE and GFP_RECLAIMABLE.
Link: https://lkml.kernel.org/r/1718845190-4456-1-git-send-email-yangge1116@126.com
Fixes: 5d0a661d808f ("mm/page_alloc: use only one PCP list for THP-sized allocations")
Signed-off-by: yangge <yangge1116@126.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As Ying pointed out in [1], stats->nr_thp_failed needs to be updated to
avoid stats inconsistency between MIGRATE_SYNC and MIGRATE_ASYNC when
calling migrate_pages_batch().
Because if not, when migrate_pages_batch() is called via
migrate_pages(MIGRATE_ASYNC), nr_thp_failed will not be increased and when
migrate_pages_batch() is called via migrate_pages(MIGRATE_SYNC*),
nr_thp_failed will be increase in migrate_pages_sync() by
stats->nr_thp_failed += astats.nr_thp_split.
[1] https://lore.kernel.org/linux-mm/87msnq7key.fsf@yhuang6-desk2.ccr.corp.intel.com/
Link: https://lkml.kernel.org/r/20240620012712.19804-1-zi.yan@sent.com
Link: https://lkml.kernel.org/r/20240618134151.29214-1-zi.yan@sent.com
Fixes: 7262f208ca68 ("mm/migrate: split source folio if it is on deferred split list")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 29d7355a9d05 ("kasan: save alloc stack traces for mempool") messed
up one of the calls to unpoison_slab_object: the last two arguments are
supposed to be GFP flags and whether to init the object memory.
Fix the call.
Without this fix, __kasan_mempool_unpoison_object provides the object's
size as GFP flags to unpoison_slab_object, which can cause LOCKDEP reports
(and probably other issues).
Link: https://lkml.kernel.org/r/20240614143238.60323-1-andrey.konovalov@linux.dev
Fixes: 29d7355a9d05 ("kasan: save alloc stack traces for mempool")
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reported-by: Brad Spengler <spender@grsecurity.net>
Acked-by: Marco Elver <elver@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
During compaction isolated free pages are marked allocated so that they
can be split and/or freed. For that, post_alloc_hook() is used inside
split_map_pages() and release_free_list(). split_map_pages() marks free
pages allocated, splits the pages and then lets
alloc_contig_range_noprof() free those pages. release_free_list() marks
free pages and immediately frees them. This usage of post_alloc_hook()
affect memory allocation profiling because these functions might not be
called from an instrumented allocator, therefore current->alloc_tag is
NULL and when debugging is enabled (CONFIG_MEM_ALLOC_PROFILING_DEBUG=y)
that causes warnings. To avoid that, wrap such post_alloc_hook() calls
into an instrumented function which acts as an allocator which will be
charged for these fake allocations. Note that these allocations are very
short lived until they are freed, therefore the associated counters should
usually read 0.
Link: https://lkml.kernel.org/r/20240614230504.3849136-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Sourav Panda <souravpanda@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
slab_post_alloc_hook() uses prepare_slab_obj_exts_hook() to obtain
slabobj_ext object. Currently the only user of slabobj_ext object in this
path is memory allocation profiling, therefore when it's not enabled this
object is not needed. This also generates a warning when compiling with
CONFIG_MEM_ALLOC_PROFILING=n. Move the code under this configuration to
fix the warning. If more slabobj_ext users appear in the future, the code
will have to be changed back to call prepare_slab_obj_exts_hook().
Link: https://lkml.kernel.org/r/20240614225951.3845577-1-surenb@google.com
Fixes: 4b8736964640 ("mm/slab: add allocation accounting into slab allocation and free paths")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406150444.F6neSaiy-lkp@intel.com/
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use numa_valid_node() function to verify that nid is a valid node ID
instead of inconsistent comparisons with either NUMA_NO_NODE or
MAX_NUMNODES.
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Merge tag 'fixes-2024-06-23' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
Pull memblock fix from Mike Rapoport:
"Fix fragility in checks for unset node ID.
Use numa_valid_node() function to verify that nid is a valid node
ID instead of inconsistent comparisons with either NUMA_NO_NODE or
MAX_NUMNODES"
* tag 'fixes-2024-06-23' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
memblock: use numa_valid_node() helper to check for invalid node ID
Mainly MM singleton fixes. And a couple of ocfs2 regression fixes.
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Merge tag 'mm-hotfixes-stable-2024-06-17-11-43' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"Mainly MM singleton fixes. And a couple of ocfs2 regression fixes"
* tag 'mm-hotfixes-stable-2024-06-17-11-43' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
kcov: don't lose track of remote references during softirqs
mm: shmem: fix getting incorrect lruvec when replacing a shmem folio
mm/debug_vm_pgtable: drop RANDOM_ORVALUE trick
mm: fix possible OOB in numa_rebuild_large_mapping()
mm/migrate: fix kernel BUG at mm/compaction.c:2761!
selftests: mm: make map_fixed_noreplace test names stable
mm/memfd: add documentation for MFD_NOEXEC_SEAL MFD_EXEC
mm: mmap: allow for the maximum number of bits for randomizing mmap_base by default
gcov: add support for GCC 14
zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING
mm: huge_memory: fix misused mapping_large_folio_support() for anon folios
lib/alloc_tag: fix RCU imbalance in pgalloc_tag_get()
lib/alloc_tag: do not register sysctl interface when CONFIG_SYSCTL=n
MAINTAINERS: remove Lorenzo as vmalloc reviewer
Revert "mm: init_mlocked_on_free_v3"
mm/page_table_check: fix crash on ZONE_DEVICE
gcc: disable '-Warray-bounds' for gcc-9
ocfs2: fix NULL pointer dereference in ocfs2_abort_trigger()
ocfs2: fix NULL pointer dereference in ocfs2_journal_dirty()
Introduce numa_valid_node(nid) that verifies that nid is a valid node ID
and use that instead of comparing nid parameter with either NUMA_NO_NODE
or MAX_NUMNODES.
This makes the checks for valid node IDs consistent and more robust and
allows to get rid of multiple WARNings.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
When testing shmem swapin, I encountered the warning below on my machine.
The reason is that replacing an old shmem folio with a new one causes
mem_cgroup_migrate() to clear the old folio's memcg data. As a result,
the old folio cannot get the correct memcg's lruvec needed to remove
itself from the LRU list when it is being freed. This could lead to
possible serious problems, such as LRU list crashes due to holding the
wrong LRU lock, and incorrect LRU statistics.
To fix this issue, we can fallback to use the mem_cgroup_replace_folio()
to replace the old shmem folio.
[ 5241.100311] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5d9960
[ 5241.100317] head: order:4 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[ 5241.100319] flags: 0x17fffe0000040068(uptodate|lru|head|swapbacked|node=0|zone=2|lastcpupid=0x3ffff)
[ 5241.100323] raw: 17fffe0000040068 fffffdffd6687948 fffffdffd69ae008 0000000000000000
[ 5241.100325] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[ 5241.100326] head: 17fffe0000040068 fffffdffd6687948 fffffdffd69ae008 0000000000000000
[ 5241.100327] head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[ 5241.100328] head: 17fffe0000000204 fffffdffd6665801 ffffffffffffffff 0000000000000000
[ 5241.100329] head: 0000000a00000010 0000000000000000 00000000ffffffff 0000000000000000
[ 5241.100330] page dumped because: VM_WARN_ON_ONCE_FOLIO(!memcg && !mem_cgroup_disabled())
[ 5241.100338] ------------[ cut here ]------------
[ 5241.100339] WARNING: CPU: 19 PID: 78402 at include/linux/memcontrol.h:775 folio_lruvec_lock_irqsave+0x140/0x150
[...]
[ 5241.100374] pc : folio_lruvec_lock_irqsave+0x140/0x150
[ 5241.100375] lr : folio_lruvec_lock_irqsave+0x138/0x150
[ 5241.100376] sp : ffff80008b38b930
[...]
[ 5241.100398] Call trace:
[ 5241.100399] folio_lruvec_lock_irqsave+0x140/0x150
[ 5241.100401] __page_cache_release+0x90/0x300
[ 5241.100404] __folio_put+0x50/0x108
[ 5241.100406] shmem_replace_folio+0x1b4/0x240
[ 5241.100409] shmem_swapin_folio+0x314/0x528
[ 5241.100411] shmem_get_folio_gfp+0x3b4/0x930
[ 5241.100412] shmem_fault+0x74/0x160
[ 5241.100414] __do_fault+0x40/0x218
[ 5241.100417] do_shared_fault+0x34/0x1b0
[ 5241.100419] do_fault+0x40/0x168
[ 5241.100420] handle_pte_fault+0x80/0x228
[ 5241.100422] __handle_mm_fault+0x1c4/0x440
[ 5241.100424] handle_mm_fault+0x60/0x1f0
[ 5241.100426] do_page_fault+0x120/0x488
[ 5241.100429] do_translation_fault+0x4c/0x68
[ 5241.100431] do_mem_abort+0x48/0xa0
[ 5241.100434] el0_da+0x38/0xc0
[ 5241.100436] el0t_64_sync_handler+0x68/0xc0
[ 5241.100437] el0t_64_sync+0x14c/0x150
[ 5241.100439] ---[ end trace 0000000000000000 ]---
[baolin.wang@linux.alibaba.com: remove less helpful comments, per Matthew]
Link: https://lkml.kernel.org/r/ccad3fe1375b468ebca3227b6b729f3eaf9d8046.1718423197.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/3c11000dd6c1df83015a8321a859e9775ebbc23e.1718266112.git.baolin.wang@linux.alibaba.com
Fixes: 85ce2c517ade ("memcontrol: only transfer the memcg data for migration")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Macro RANDOM_ORVALUE was used to make sure the pgtable entry will be
populated with !none data in clear tests.
The RANDOM_ORVALUE tried to cover mostly all the bits in a pgtable entry,
even if there's no discussion on whether all the bits will be vaild. Both
S390 and PPC64 have their own masks to avoid touching some bits. Now it's
the turn for x86_64.
The issue is there's a recent report from Mikhail Gavrilov showing that
this can cause a warning with the newly added pte set check in commit
8430557fc5 on writable v.s. userfaultfd-wp bit, even though the check
itself was valid, the random pte is not. We can choose to mask more bits
out.
However the need to have such random bits setup is questionable, as now
it's already guaranteed to be true on below:
- For pte level, the pgtable entry will be installed with value from
pfn_pte(), where pfn points to a valid page. Hence the pte will be
!none already if populated with pfn_pte().
- For upper-than-pte level, the pgtable entry should contain a directory
entry always, which is also !none.
All the cases look like good enough to test a pxx_clear() helper. Instead
of extending the bitmask, drop the "set random bits" trick completely. Add
some warning guards to make sure the entries will be !none before clear().
Link: https://lkml.kernel.org/r/20240523132139.289719-1-peterx@redhat.com
Fixes: 8430557fc584 ("mm/page_table_check: support userfault wr-protect entries")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Link: https://lore.kernel.org/r/CABXGCsMB9A8-X+Np_Q+fWLURYL_0t3Y-MdoNabDM-Lzk58-DGA@mail.gmail.com
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
I hit the VM_BUG_ON(!list_empty(&cc->migratepages)) in compact_zone(); and
if DEBUG_VM were off, then pages would be lost on a local list.
Our convention is that if migrate_pages() reports complete success (0),
then the migratepages list will be empty; but if it reports an error or
some pages remaining, then its caller must putback_movable_pages().
There's a new case in which migrate_pages() has been reporting complete
success, but returning with pages left on the migratepages list: when
migrate_pages_batch() successfully split a folio on the deferred list, but
then the "Failure isn't counted" call does not dispose of them all.
Since that block is expecting the large folio to have been counted as 1
failure already, and since the return code is later adjusted to success
whenever the returned list is found empty, the simple way to fix this
safely is to count splitting the deferred folio as "a failure".
Link: https://lkml.kernel.org/r/46c948b4-4dd8-6e03-4c7b-ce4e81cfa536@google.com
Fixes: 7262f208ca68 ("mm/migrate: split source folio if it is on deferred split list")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When I did a large folios split test, a WARNING "[ 5059.122759][ T166]
Cannot split file folio to non-0 order" was triggered. But the test cases
are only for anonmous folios. while mapping_large_folio_support() is only
reasonable for page cache folios.
In split_huge_page_to_list_to_order(), the folio passed to
mapping_large_folio_support() maybe anonmous folio. The folio_test_anon()
check is missing. So the split of the anonmous THP is failed. This is
also the same for shmem_mapping(). We'd better add a check for both. But
the shmem_mapping() in __split_huge_page() is not involved, as for
anonmous folios, the end parameter is set to -1, so (head[i].index >= end)
is always false. shmem_mapping() is not called.
Also add a VM_WARN_ON_ONCE() in mapping_large_folio_support() for anon
mapping, So we can detect the wrong use more easily.
THP folios maybe exist in the pagecache even the file system doesn't
support large folio, it is because when CONFIG_TRANSPARENT_HUGEPAGE is
enabled, khugepaged will try to collapse read-only file-backed pages to
THP. But the mapping does not actually support multi order large folios
properly.
Using /sys/kernel/debug/split_huge_pages to verify this, with this patch,
large anon THP is successfully split and the warning is ceased.
Link: https://lkml.kernel.org/r/202406071740485174hcFl7jRxncsHDtI-Pz-o@zte.com.cn
Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages")
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There was insufficient review and no agreement that this is the right
approach.
There are serious flaws with the implementation that make processes using
mlock() not even work with simple fork() [1] and we get reliable crashes
when rebooting.
Further, simply because we might be unmapping a single PTE of a large
mlocked folio, we shouldn't zero out the whole folio.
... especially because the code can also *corrupt* urelated memory because
kernel_init_pages(page, folio_nr_pages(folio));
Could end up writing outside of the actual folio if we work with a tail
page.
Let's revert it. Once there is agreement that this is the right approach,
the issues were fixed and there was reasonable review and proper testing,
we can consider it again.
[1] https://lkml.kernel.org/r/4da9da2f-73e4-45fd-b62f-a8a513314057@redhat.com
Link: https://lkml.kernel.org/r/20240605091710.38961-1-david@redhat.com
Fixes: ba42b524a040 ("mm: init_mlocked_on_free_v3")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: David Wang <00107082@163.com>
Closes: https://lore.kernel.org/lkml/20240528151340.4282-1-00107082@163.com/
Reported-by: Lance Yang <ioworker0@gmail.com>
Closes: https://lkml.kernel.org/r/20240601140917.43562-1-ioworker0@gmail.com
Acked-by: Lance Yang <ioworker0@gmail.com>
Cc: York Jasper Niebuhr <yjnworkstation@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Not all pages may apply to pgtable check. One example is ZONE_DEVICE
pages: they map PFNs directly, and they don't allocate page_ext at all
even if there's struct page around. One may reference
devm_memremap_pages().
When both ZONE_DEVICE and page-table-check enabled, then try to map some
dax memories, one can trigger kernel bug constantly now when the kernel
was trying to inject some pfn maps on the dax device:
kernel BUG at mm/page_table_check.c:55!
While it's pretty legal to use set_pxx_at() for ZONE_DEVICE pages for page
fault resolutions, skip all the checks if page_ext doesn't even exist in
pgtable checker, which applies to ZONE_DEVICE but maybe more.
Link: https://lkml.kernel.org/r/20240605212146.994486-1-peterx@redhat.com
Fixes: df4e817b7108 ("mm: page table check")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
To check for unset node ID for a range memblock_validate_numa_coverage()
was checking for NUMA_NO_NODE, but x86 used MAX_NUMNODES when no node ID
was specified by buggy firmware.
Update memblock to substitute MAX_NUMNODES with NUMA_NO_NODE in
memblock_set_node() and use NUMA_NO_NODE in x86::numa_init().
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Merge tag 'fixes-2024-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
Pull memblock fixes from Mike Rapoport:
"Fix validation of NUMA coverage.
memblock_validate_numa_coverage() was checking for a unset node ID
using NUMA_NO_NODE, but x86 used MAX_NUMNODES when no node ID was
specified by buggy firmware.
Update memblock to substitute MAX_NUMNODES with NUMA_NO_NODE in
memblock_set_node() and use NUMA_NO_NODE in x86::numa_init()"
* tag 'fixes-2024-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
x86/mm/numa: Use NUMA_NO_NODE when calling memblock_set_node()
memblock: make memblock_set_node() also warn about use of MAX_NUMNODES
GCC 14.1 complains about the argument usage of kmemdup_array():
drivers/soc/tegra/fuse/fuse-tegra.c:130:65: error: 'kmemdup_array' sizes specified with 'sizeof' in the earlier argument and not in the later argument [-Werror=calloc-transposed-args]
130 | fuse->lookups = kmemdup_array(fuse->soc->lookups, sizeof(*fuse->lookups),
| ^
drivers/soc/tegra/fuse/fuse-tegra.c:130:65: note: earlier argument should specify number of elements, later size of each element
The annotation introduced by commit 7d78a7773355 ("string: Add
additional __realloc_size() annotations for "dup" helpers") lets the
compiler think that kmemdup_array() follows the same format as calloc(),
with the number of elements preceding the size of one element. So we
could simply swap the arguments to __realloc_size() to get rid of that
warning, but it seems cleaner to instead have kmemdup_array() follow the
same format as krealloc_array(), memdup_array_user(), calloc() etc.
Fixes: 7d78a7773355 ("string: Add additional __realloc_size() annotations for "dup" helpers")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240606144608.97817-2-jean-philippe@linaro.org
Signed-off-by: Kees Cook <kees@kernel.org>
Grepping /proc/allocinfo for "noprof" reveals several xyz_noprof
functions, which means internally they are calling profiled functions.
This should never happen as such calls move allocation charge from a
higher level location where it should be accounted for into these lower
level helpers. Fix this by replacing profiled function calls with noprof
ones.
Link: https://lkml.kernel.org/r/20240531205350.3973009-1-surenb@google.com
Fixes: b951aaff5035 ("mm: enable page allocation tagging")
Fixes: e26d8769da6d ("mempool: hook up to memory allocation profiling")
Fixes: 88ae5fb755b0 ("mm: vmalloc: enable memory allocation profiling")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Reviewed-by: Kees Cook <kees@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We normally ksm_zero_pages++ in ksmd when page is merged with zero page,
but ksm_zero_pages-- is done from page tables side, where there is no any
accessing protection of ksm_zero_pages.
So we can read very exceptional value of ksm_zero_pages in rare cases,
such as -1, which is very confusing to users.
Fix it by changing to use atomic_long_t, and the same case with the
mm->ksm_zero_pages.
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-2-34bb358fdc13@linux.dev
Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM")
Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process")
Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Stefan Roesch <shr@devkernel.io>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/ksm: fix some accounting problems", v3.
We encountered some abnormal ksm_pages_scanned and ksm_zero_pages during
some random tests.
1. ksm_pages_scanned unchanged even ksmd scanning has progress.
2. ksm_zero_pages maybe -1 in some rare cases.
This patch (of 2):
During testing, I found ksm_pages_scanned is unchanged although the
scan_get_next_rmap_item() did return valid rmap_item that is not NULL.
The reason is the scan_get_next_rmap_item() will return NULL after a full
scan, so ksm_do_scan() just return without accounting of the
ksm_pages_scanned.
Fix it by just putting ksm_pages_scanned accounting in that loop, and it
will be accounted more timely if that loop would last for a long time.
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-0-34bb358fdc13@linux.dev
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-1-34bb358fdc13@linux.dev
Fixes: b348b5fe2b5f ("mm/ksm: add pages scanned metric")
Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Stefan Roesch <shr@devkernel.io>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Li Zhijian
Yu Zhao
Tetsuo Handa
Miaohe Lin
Aristeu Rozanski
Gavin Shan
Yang Shi
ZhangPeng
Hugh Dickins
Nhat Pham
SeongJae Park
Uladzislau Rezki (Sony)
Jan Kara
Andrew Bresticker
yangge
Zi Yan
Andrey Konovalov
Suren Baghdasaryan
Jeff Xu
Zhaoyang Huang
Linus Torvalds
Mike Rapoport (IBM)
Baolin Wang
Peter Xu
Kefeng Wang
Ran Xiaokai
David Hildenbrand
Jean-Philippe Brucker
Thadeu Lima de Souza Cascardo
Oscar Salvador
Chengming Zhou