| Commit message (Collapse) | Author | Age | Files | Lines |
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In zswap_cpu_comp_prepare(), allocations are made and assigned to various
members of acomp_ctx under acomp_ctx->mutex. However, allocations may
recurse into zswap through reclaim, trying to acquire the same mutex and
deadlocking.
Move the allocations before the mutex critical section. Only the
initialization of acomp_ctx needs to be done with the mutex held.
Link: https://lkml.kernel.org/r/20250113214458.2123410-1-yosryahmed@google.com
Fixes: 12dcb0ef5406 ("mm: zswap: properly synchronize freeing resources during CPU hotunplug")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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syzkaller reported such a BUG_ON():
------------[ cut here ]------------
kernel BUG at mm/khugepaged.c:1835!
Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
...
CPU: 6 UID: 0 PID: 8009 Comm: syz.15.106 Kdump: loaded Tainted: G W 6.13.0-rc6 #22
Tainted: [W]=WARN
Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : collapse_file+0xa44/0x1400
lr : collapse_file+0x88/0x1400
sp : ffff80008afe3a60
...
Call trace:
collapse_file+0xa44/0x1400 (P)
hpage_collapse_scan_file+0x278/0x400
madvise_collapse+0x1bc/0x678
madvise_vma_behavior+0x32c/0x448
madvise_walk_vmas.constprop.0+0xbc/0x140
do_madvise.part.0+0xdc/0x2c8
__arm64_sys_madvise+0x68/0x88
invoke_syscall+0x50/0x120
el0_svc_common.constprop.0+0xc8/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x34/0x128
el0t_64_sync_handler+0xc8/0xd0
el0t_64_sync+0x190/0x198
This indicates that the pgoff is unaligned. After analysis, I confirm the
vma is mapped to /dev/zero. Such a vma certainly has vm_file, but it is
set to anonymous by mmap_zero(). So even if it's mmapped by 2m-unaligned,
it can pass the check in thp_vma_allowable_order() as it is an
anonymous-mmap, but then be collapsed as a file-mmap.
It seems the problem has existed for a long time, but actually, since we
have khugepaged_max_ptes_none check before, we will skip collapse it as it
is /dev/zero and so has no present page. But commit d8ea7cc8547c limit
the check for only khugepaged, so the BUG_ON() can be triggered by
madvise_collapse().
Add vma_is_anonymous() check to make such vma be processed by
hpage_collapse_scan_pmd().
Link: https://lkml.kernel.org/r/20250111034511.2223353-1-liushixin2@huawei.com
Fixes: d8ea7cc8547c ("mm/khugepaged: add flag to predicate khugepaged-only behavior")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Yang Shi <yang@os.amperecomputing.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mattew Wilcox <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Fixes an issue where the use of an unsigned data type in
`shmem_parse_opt_casefold()` caused incorrect evaluation of negative
conditions.
Link: https://lkml.kernel.org/r/20250111-unsignedcompare1601569-v3-1-c861b4221831@gmail.com
Fixes: 58e55efd6c72 ("tmpfs: Add casefold lookup support")
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Karan Sanghavi <karansanghvi98@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Hugh Dickens <hughd@google.com>
Cc: Shuah khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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adjust_managed_page_count
In the kernel, the zone's lowmem_reserve and _watermark, and the global
variable 'totalreserve_pages' depend on the value of managed_pages, but
after running adjust_managed_page_count, these values aren't updated,
which causes some problems.
For example, in a system with six 1GB large pages, we found that the value
of protection in zoneinfo (zone->lowmem_reserve), is not right. Its value
seems to be calculated from the initial managed_pages, but after the
managed_pages changed, was not updated. Only after reading the file
/proc/sys/vm/lowmem_reserve_ratio, updates happen.
read file /proc/sys/vm/lowmem_reserve_ratio:
lowmem_reserve_ratio_sysctl_handler
----setup_per_zone_lowmem_reserve
--------calculate_totalreserve_pages
protection changed after reading file:
[root@test ~]# cat /proc/zoneinfo | grep protection
protection: (0, 2719, 57360, 0)
protection: (0, 0, 54640, 0)
protection: (0, 0, 0, 0)
protection: (0, 0, 0, 0)
[root@test ~]# cat /proc/sys/vm/lowmem_reserve_ratio
256 256 32 0
[root@test ~]# cat /proc/zoneinfo | grep protection
protection: (0, 2735, 63524, 0)
protection: (0, 0, 60788, 0)
protection: (0, 0, 0, 0)
protection: (0, 0, 0, 0)
lowmem_reserve increased also makes the totalreserve_pages increased,
which causes a decrease in available memory. The one above is just a test
machine, and the increase is not significant. On our online machine, the
reserved memory will increase by several GB due to reading this file. It
is clearly unreasonable to cause a sharp drop in available memory just by
reading a file.
In this patch, we update reserve memory when update managed_pages, The
size of reserved memory becomes stable. But it seems that the _watermark
should also be updated along with the managed_pages. We have not done it
because we are unsure if it is reasonable to set the watermark through the
initial managed_pages. If it is not reasonable, we will propose new
patch.
Link: https://lkml.kernel.org/r/20241225021034.45693-1-15645113830zzh@gmail.com
Signed-off-by: zihan zhou <15645113830zzh@gmail.com>
Signed-off-by: yaowenchao <yaowenchao@jd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We only need to assert that the uptodate flag is clear if we're going to
set it. This hasn't been a problem before now because we have only used
folio_end_read() when completing with an error, but it's convenient to use
it in squashfs if we discover the folio is already uptodate.
Link: https://lkml.kernel.org/r/20250110163300.3346321-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When MGLRU is enabled, the pgdemote_kswapd, pgdemote_direct, and
pgdemote_khugepaged stats in vmstat are not being updated.
Commit f77f0c751478 ("mm,memcg: provide per-cgroup counters for NUMA
balancing operations") moved the pgdemote vmstat update from
demote_folio_list() to shrink_inactive_list(), which is in the normal LRU
path. As a result, the pgdemote stats are updated correctly for the
normal LRU but not for MGLRU.
To address this, we have added the pgdemote stat update in the
evict_folios() function, which is in the MGLRU path. With this patch, the
pgdemote stats will now be updated correctly when MGLRU is enabled.
Without this patch vmstat output when MGLRU is enabled
======================================================
pgdemote_kswapd 0
pgdemote_direct 0
pgdemote_khugepaged 0
With this patch vmstat output when MGLRU is enabled
===================================================
pgdemote_kswapd 43234
pgdemote_direct 4691
pgdemote_khugepaged 0
Link: https://lkml.kernel.org/r/20250109060540.451261-1-donettom@linux.ibm.com
Fixes: f77f0c751478 ("mm,memcg: provide per-cgroup counters for NUMA balancing operations")
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Cc: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kaiyang Zhao <kaiyang2@cs.cmu.edu>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The upstream commit adcfb264c3ed ("vmstat: disable vmstat_work on
vmstat_cpu_down_prep()") introduced another warning during the boot phase
so was soon reverted on upstream by commit cd6313beaeae ("Revert "vmstat:
disable vmstat_work on vmstat_cpu_down_prep()""). This commit resolves it
and reattempts the original fix.
Even after mm/vmstat:online teardown, shepherd may still queue work for
the dying cpu until the cpu is removed from online mask. While it's quite
rare, this means that after unbind_workers() unbinds a per-cpu kworker, it
potentially runs vmstat_update for the dying CPU on an irrelevant cpu
before entering atomic AP states. When CONFIG_DEBUG_PREEMPT=y, it results
in the following error with the backtrace.
BUG: using smp_processor_id() in preemptible [00000000] code: \
kworker/7:3/1702
caller is refresh_cpu_vm_stats+0x235/0x5f0
CPU: 0 UID: 0 PID: 1702 Comm: kworker/7:3 Tainted: G
Tainted: [N]=TEST
Workqueue: mm_percpu_wq vmstat_update
Call Trace:
<TASK>
dump_stack_lvl+0x8d/0xb0
check_preemption_disabled+0xce/0xe0
refresh_cpu_vm_stats+0x235/0x5f0
vmstat_update+0x17/0xa0
process_one_work+0x869/0x1aa0
worker_thread+0x5e5/0x1100
kthread+0x29e/0x380
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
So, for mm/vmstat:online, disable vmstat_work reliably on teardown and
symmetrically enable it on startup.
For secondary CPUs during CPU hotplug scenarios, ensure the delayed work
is disabled immediately after the initialization. These CPUs are not yet
online when start_shepherd_timer() runs on boot CPU. vmstat_cpu_online()
will enable the work for them.
Link: https://lkml.kernel.org/r/20250108042807.3429745-1-koichiro.den@canonical.com
Signed-off-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Suggested-by: Huacai Chen <chenhuacai@kernel.org>
Tested-by: Charalampos Mitrodimas <charmitro@posteo.net>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When mremap()ing a memory region previously registered with userfaultfd as
write-protected but without UFFD_FEATURE_EVENT_REMAP, an inconsistency in
flag clearing leads to a mismatch between the vma flags (which have
uffd-wp cleared) and the pte/pmd flags (which do not have uffd-wp
cleared). This mismatch causes a subsequent mprotect(PROT_WRITE) to
trigger a warning in page_table_check_pte_flags() due to setting the pte
to writable while uffd-wp is still set.
Fix this by always explicitly clearing the uffd-wp pte/pmd flags on any
such mremap() so that the values are consistent with the existing clearing
of VM_UFFD_WP. Be careful to clear the logical flag regardless of its
physical form; a PTE bit, a swap PTE bit, or a PTE marker. Cover PTE,
huge PMD and hugetlb paths.
Link: https://lkml.kernel.org/r/20250107144755.1871363-2-ryan.roberts@arm.com
Co-developed-by: Mikołaj Lenczewski <miko.lenczewski@arm.com>
Signed-off-by: Mikołaj Lenczewski <miko.lenczewski@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Closes: https://lore.kernel.org/linux-mm/810b44a8-d2ae-4107-b665-5a42eae2d948@arm.com/
Fixes: 63b2d4174c4a ("userfaultfd: wp: add the writeprotect API to userfaultfd ioctl")
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the
current CPU at the beginning of the operation is retrieved and used
throughout. However, since neither preemption nor migration are disabled,
it is possible that the operation continues on a different CPU.
If the original CPU is hotunplugged while the acomp_ctx is still in use,
we run into a UAF bug as some of the resources attached to the acomp_ctx
are freed during hotunplug in zswap_cpu_comp_dead() (i.e.
acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp).
The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use
crypto_acomp API for hardware acceleration") when the switch to the
crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was
retrieved using get_cpu_ptr() which disables preemption and makes sure the
CPU cannot go away from under us. Preemption cannot be disabled with the
crypto_acomp API as a sleepable context is needed.
Use the acomp_ctx.mutex to synchronize CPU hotplug callbacks allocating
and freeing resources with compression/decompression paths. Make sure
that acomp_ctx.req is NULL when the resources are freed. In the
compression/decompression paths, check if acomp_ctx.req is NULL after
acquiring the mutex (meaning the CPU was offlined) and retry on the new
CPU.
The initialization of acomp_ctx.mutex is moved from the CPU hotplug
callback to the pool initialization where it belongs (where the mutex is
allocated). In addition to adding clarity, this makes sure that CPU
hotplug cannot reinitialize a mutex that is already locked by
compression/decompression.
Previously a fix was attempted by holding cpus_read_lock() [1]. This
would have caused a potential deadlock as it is possible for code already
holding the lock to fall into reclaim and enter zswap (causing a
deadlock). A fix was also attempted using SRCU for synchronization, but
Johannes pointed out that synchronize_srcu() cannot be used in CPU hotplug
notifiers [2].
Alternative fixes that were considered/attempted and could have worked:
- Refcounting the per-CPU acomp_ctx. This involves complexity in
handling the race between the refcount dropping to zero in
zswap_[de]compress() and the refcount being re-initialized when the
CPU is onlined.
- Disabling migration before getting the per-CPU acomp_ctx [3], but
that's discouraged and is a much bigger hammer than needed, and could
result in subtle performance issues.
[1]https://lkml.kernel.org/20241219212437.2714151-1-yosryahmed@google.com/
[2]https://lkml.kernel.org/20250107074724.1756696-2-yosryahmed@google.com/
[3]https://lkml.kernel.org/20250107222236.2715883-2-yosryahmed@google.com/
[yosryahmed@google.com: remove comment]
Link: https://lkml.kernel.org/r/CAJD7tkaxS1wjn+swugt8QCvQ-rVF5RZnjxwPGX17k8x9zSManA@mail.gmail.com
Link: https://lkml.kernel.org/r/20250108222441.3622031-1-yosryahmed@google.com
Fixes: 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Closes: https://lore.kernel.org/lkml/20241113213007.GB1564047@cmpxchg.org/
Reported-by: Sam Sun <samsun1006219@gmail.com>
Closes: https://lore.kernel.org/lkml/CAEkJfYMtSdM5HceNsXUDf5haghD5+o2e7Qv4OcuruL4tPg6OaQ@mail.gmail.com/
Cc: Barry Song <baohua@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This reverts commit eaebeb93922ca6ab0dd92027b73d0112701706ef.
Commit eaebeb93922c ("mm: zswap: fix race between [de]compression and CPU
hotunplug") used the CPU hotplug lock in zswap compress/decompress
operations to protect against a race with CPU hotunplug making some
per-CPU resources go away.
However, zswap compress/decompress can be reached through reclaim while
the lock is held, resulting in a potential deadlock as reported by syzbot:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc6-syzkaller-00006-g5428dc1906dd #0 Not tainted
------------------------------------------------------
kswapd0/89 is trying to acquire lock:
ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: acomp_ctx_get_cpu mm/zswap.c:886 [inline]
ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_compress mm/zswap.c:908 [inline]
ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_store_page mm/zswap.c:1439 [inline]
ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_store+0xa74/0x1ba0 mm/zswap.c:1546
but task is already holding lock:
ffffffff8ea355a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6871 [inline]
ffffffff8ea355a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb58/0x2f30 mm/vmscan.c:7253
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__fs_reclaim_acquire mm/page_alloc.c:3853 [inline]
fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3867
might_alloc include/linux/sched/mm.h:318 [inline]
slab_pre_alloc_hook mm/slub.c:4070 [inline]
slab_alloc_node mm/slub.c:4148 [inline]
__kmalloc_cache_node_noprof+0x40/0x3a0 mm/slub.c:4337
kmalloc_node_noprof include/linux/slab.h:924 [inline]
alloc_worker kernel/workqueue.c:2638 [inline]
create_worker+0x11b/0x720 kernel/workqueue.c:2781
workqueue_prepare_cpu+0xe3/0x170 kernel/workqueue.c:6628
cpuhp_invoke_callback+0x48d/0x830 kernel/cpu.c:194
__cpuhp_invoke_callback_range kernel/cpu.c:965 [inline]
cpuhp_invoke_callback_range kernel/cpu.c:989 [inline]
cpuhp_up_callbacks kernel/cpu.c:1020 [inline]
_cpu_up+0x2b3/0x580 kernel/cpu.c:1690
cpu_up+0x184/0x230 kernel/cpu.c:1722
cpuhp_bringup_mask+0xdf/0x260 kernel/cpu.c:1788
cpuhp_bringup_cpus_parallel+0xf9/0x160 kernel/cpu.c:1878
bringup_nonboot_cpus+0x2b/0x50 kernel/cpu.c:1892
smp_init+0x34/0x150 kernel/smp.c:1009
kernel_init_freeable+0x417/0x5d0 init/main.c:1569
kernel_init+0x1d/0x2b0 init/main.c:1466
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #0 (cpu_hotplug_lock){++++}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
cpus_read_lock+0x42/0x150 kernel/cpu.c:490
acomp_ctx_get_cpu mm/zswap.c:886 [inline]
zswap_compress mm/zswap.c:908 [inline]
zswap_store_page mm/zswap.c:1439 [inline]
zswap_store+0xa74/0x1ba0 mm/zswap.c:1546
swap_writepage+0x647/0xce0 mm/page_io.c:279
shmem_writepage+0x1248/0x1610 mm/shmem.c:1579
pageout mm/vmscan.c:696 [inline]
shrink_folio_list+0x35ee/0x57e0 mm/vmscan.c:1374
shrink_inactive_list mm/vmscan.c:1967 [inline]
shrink_list mm/vmscan.c:2205 [inline]
shrink_lruvec+0x16db/0x2f30 mm/vmscan.c:5734
mem_cgroup_shrink_node+0x385/0x8e0 mm/vmscan.c:6575
mem_cgroup_soft_reclaim mm/memcontrol-v1.c:312 [inline]
memcg1_soft_limit_reclaim+0x346/0x810 mm/memcontrol-v1.c:362
balance_pgdat mm/vmscan.c:6975 [inline]
kswapd+0x17b3/0x2f30 mm/vmscan.c:7253
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(cpu_hotplug_lock);
lock(fs_reclaim);
rlock(cpu_hotplug_lock);
*** DEADLOCK ***
1 lock held by kswapd0/89:
#0: ffffffff8ea355a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6871 [inline]
#0: ffffffff8ea355a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb58/0x2f30 mm/vmscan.c:7253
stack backtrace:
CPU: 0 UID: 0 PID: 89 Comm: kswapd0 Not tainted 6.13.0-rc6-syzkaller-00006-g5428dc1906dd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
cpus_read_lock+0x42/0x150 kernel/cpu.c:490
acomp_ctx_get_cpu mm/zswap.c:886 [inline]
zswap_compress mm/zswap.c:908 [inline]
zswap_store_page mm/zswap.c:1439 [inline]
zswap_store+0xa74/0x1ba0 mm/zswap.c:1546
swap_writepage+0x647/0xce0 mm/page_io.c:279
shmem_writepage+0x1248/0x1610 mm/shmem.c:1579
pageout mm/vmscan.c:696 [inline]
shrink_folio_list+0x35ee/0x57e0 mm/vmscan.c:1374
shrink_inactive_list mm/vmscan.c:1967 [inline]
shrink_list mm/vmscan.c:2205 [inline]
shrink_lruvec+0x16db/0x2f30 mm/vmscan.c:5734
mem_cgroup_shrink_node+0x385/0x8e0 mm/vmscan.c:6575
mem_cgroup_soft_reclaim mm/memcontrol-v1.c:312 [inline]
memcg1_soft_limit_reclaim+0x346/0x810 mm/memcontrol-v1.c:362
balance_pgdat mm/vmscan.c:6975 [inline]
kswapd+0x17b3/0x2f30 mm/vmscan.c:7253
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Revert the change. A different fix for the race with CPU hotunplug will
follow.
Link: https://lkml.kernel.org/r/20250107222236.2715883-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sam Sun <samsun1006219@gmail.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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During testing it has been detected, that it is possible to get div by
zero error in bdi_set_min_bytes. The error is caused by the function
bdi_ratio_from_pages(). bdi_ratio_from_pages() calls global_dirty_limits.
If the dirty threshold is 0, the div by zero is raised. This can happen
if the root user is setting:
echo 0 > /proc/sys/vm/dirty_ratio
The following is a test case:
echo 0 > /proc/sys/vm/dirty_ratio
cd /sys/class/bdi/<device>
echo 1 > strict_limit
echo 8192 > min_bytes
==> error is raised.
The problem is addressed by returning -EINVAL if dirty_ratio or
dirty_bytes is set to 0.
[shr@devkernel.io: check for -EINVAL in bdi_set_min_bytes() and bdi_set_max_bytes()]
Link: https://lkml.kernel.org/r/20250108014723.166637-1-shr@devkernel.io
[shr@devkernel.io: v3]
Link: https://lkml.kernel.org/r/20250109063411.6591-1-shr@devkernel.io
Link: https://lkml.kernel.org/r/20250104012037.159386-1-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Reported-by: cheung wall <zzqq0103.hey@gmail.com>
Closes: https://lore.kernel.org/linux-mm/87pll35yd0.fsf@devkernel.io/T/#t
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Qiang Zhang <zzqq0103.hey@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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On 32-bit kernels, folio_seek_hole_data() was inadvertently truncating a
64-bit value to 32 bits, leading to a possible infinite loop when writing
to an xfs filesystem.
Link: https://lkml.kernel.org/r/20250102190540.1356838-1-marco.nelissen@gmail.com
Fixes: 54fa39ac2e00 ("iomap: use mapping_seek_hole_data")
Signed-off-by: Marco Nelissen <marco.nelissen@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit fa3bea4e1f82 introduced MPOL_WEIGHTED_INTERLEAVE but it missed
adding its counter to "interleave_hit" of numastat, which is located at
/sys/devices/system/node/nodeN/ directory.
It'd be better to add weighted interleving counter info to the existing
"interleave_hit" instead of introducing a new counter
"weighted_interleave_hit".
Link: https://lkml.kernel.org/r/20241227095737.645-1-honggyu.kim@sk.com
Fixes: fa3bea4e1f82 ("mm/mempolicy: introduce MPOL_WEIGHTED_INTERLEAVE for weighted interleaving")
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Hyeonggon Yoo <hyeonggon.yoo@sk.com>
Tested-by: Yunjeong Mun <yunjeong.mun@sk.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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kmemleak_alloc_percpu gives an incorrect min_count parameter, causing
percpu memory to be considered a gray object.
Link: https://lkml.kernel.org/r/20241227092311.3572500-1-guoweikang.kernel@gmail.com
Fixes: 8c8685928910 ("mm/kmemleak: use IS_ERR_PCPU() for pointer in the percpu address space")
Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com>
Acked-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This reverts commit adcfb264c3ed51fbbf5068ddf10d309a63683868.
It turns out this just causes a different warning splat instead that
seems to be much easier to trigger, so let's revert ASAP.
Reported-and-bisected-by: Borislav Petkov <bp@alien8.de>
Tested-by: Breno Leitao <leitao@debian.org>
Reported-by: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/all/20250106131817.GAZ3vYGVr3-hWFFPLj@fat_crate.local/
Cc: Koichiro Den <koichiro.den@canonical.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Since the string data to copy from userspace is likely less than PAGE_SIZE
bytes, replace GFP_KERNEL with GFP_USER like commit 6c2c97a24f09
("memdup_user(): switch to GFP_USER") does and add __GFP_NOWARN like
commit 6c8fcc096be9 ("mm: don't let userspace spam allocations warnings")
does. Also, use dedicated slab buckets like commit d73778e4b867
("mm/util: Use dedicated slab buckets for memdup_user()") does.
Link: https://lkml.kernel.org/r/014cd694-cc27-4a07-a34a-2ae95d744515@I-love.SAKURA.ne.jp
Reported-by: syzbot+7e12e97b36154c54414b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7e12e97b36154c54414b
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Since commit 5abc1e37afa0 ("mm: list_lru: allocate list_lru_one only when
needed"), all list_lru users need to allocate the items using the new
infrastructure that provides list_lru info for slab allocation, ensuring
that the corresponding memcg list_lru is allocated before use.
For workingset shadow nodes (which are xa_node), users are converted to
use the new infrastructure by commit 9bbdc0f32409 ("xarray: use
kmem_cache_alloc_lru to allocate xa_node"). The xas->xa_lru will be set
correctly for filemap users. However, there is a missing case: xa_node
allocations caused by madvise(..., MADV_COLLAPSE).
madvise(..., MADV_COLLAPSE) will also read in the absent parts of file
map, and there will be xa_nodes allocated for the caller's memcg (assuming
it's not rootcg). However, these allocations won't trigger memcg list_lru
allocation because the proper xas info was not set.
If nothing else has allocated other xa_nodes for that memcg to trigger
list_lru creation, and memory pressure starts to evict file pages,
workingset_update_node will try to add these xa_nodes to their
corresponding memcg list_lru, and it does not exist (NULL). So they will
be added to rootcg's list_lru instead.
This shouldn't be a significant issue in practice, but it is indeed
unexpected behavior, and these xa_nodes will not be reclaimed effectively.
And may lead to incorrect counting of the list_lru->nr_items counter.
This problem wasn't exposed until recent commit 28e98022b31ef
("mm/list_lru: simplify reparenting and initial allocation") added a
sanity check: only dying memcg could have a NULL list_lru when
list_lru_{add,del} is called. This problem triggered this WARNING.
So make madvise(..., MADV_COLLAPSE) also call xas_set_lru() to pass the
list_lru which we may want to insert xa_node into later. And move
mapping_set_update to mm/internal.h, and turn into a macro to avoid
including extra headers in mm/internal.h.
Link: https://lkml.kernel.org/r/20241222122936.67501-1-ryncsn@gmail.com
Fixes: 9bbdc0f32409 ("xarray: use kmem_cache_alloc_lru to allocate xa_node")
Reported-by: syzbot+38a0cbd267eff2d286ff@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/675d01e9.050a0220.37aaf.00be.GAE@google.com/
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damon_commit_schemes() ignores quota goals and filters of the newly
committed schemes. This makes users confused about the behaviors.
Correctly handle those inputs.
Link: https://lkml.kernel.org/r/20241222231222.85060-3-sj@kernel.org
Fixes: 9cb3d0b9dfce ("mm/damon/core: implement DAMON context commit function")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/damon/core: fix memory leaks and ignored inputs from
damon_commit_ctx()".
Due to two bugs in damon_commit_targets() and damon_commit_schemes(),
which are called from damon_commit_ctx(), some user inputs can be ignored,
and some mmeory objects can be leaked. Fix those.
Note that only DAMON sysfs interface users are affected. Other DAMON core
API user modules that more focused more on simple and dedicated production
usages, including DAMON_RECLAIM and DAMON_LRU_SORT are not using the buggy
function in the way, so not affected.
This patch (of 2):
When new DAMON targets are added via damon_commit_targets(), the newly
created targets are not deallocated when updating the internal data
(damon_commit_target()) is failed. Worse yet, even if the setup is
successfully done, the new target is not linked to the context. Hence,
the new targets are always leaked regardless of the internal data setup
failure. Fix the leaks.
Link: https://lkml.kernel.org/r/20241222231222.85060-2-sj@kernel.org
Fixes: 9cb3d0b9dfce ("mm/damon/core: implement DAMON context commit function")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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commit 2788cf0c401c ("memcg: reparent list_lrus and free kmemcg_id on css
offline") removed sanity checks for the nr_items counter's value because
it implemented list_lru re-parenting in a way that will redirect
children's list_lru to the parent before re-parenting the items in
list_lru. This will make item counter uncharging happen in the parent
while the item is still being held by the child. As a result, the
parent's counter value may become negative. This is acceptable because
re-parenting will sum up the children's counter values, and the parent's
counter will be fixed.
Later commit fb56fdf8b9a2 ("mm/list_lru: split the lock to per-cgroup
scope") reworked the re-parenting process, and removed the redirect. So
it added the sanity check back, assuming that as long as items are still
in the children's list_lru, parent's counter will not be uncharged.
But that assumption is incorrect. The xas_store in
memcg_reparent_list_lrus will set children's list_lru to NULL before
re-parenting the items, it redirects list_lru helpers to use parent's
list_lru just like before. But still, it's not a problem as re-parenting
will fix the counter.
Therefore, remove this sanity check, but add a new check to ensure that
the counter won't go negative in a different way: the child's list_lru
being re-parented should never have a negative counter, since re-parenting
should occur in order and fixes counters.
Link: https://lkml.kernel.org/r/20241223150907.1591-1-ryncsn@gmail.com
Fixes: fb56fdf8b9a2 ("mm/list_lru: split the lock to per-cgroup scope")
Signed-off-by: Kairui Song <kasong@tencent.com>
Closes: https://lore.kernel.org/lkml/Z2Bz9t92Be9l1xqj@lappy/
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Even after mm/vmstat:online teardown, shepherd may still queue work for
the dying cpu until the cpu is removed from online mask. While it's quite
rare, this means that after unbind_workers() unbinds a per-cpu kworker, it
potentially runs vmstat_update for the dying CPU on an irrelevant cpu
before entering atomic AP states. When CONFIG_DEBUG_PREEMPT=y, it results
in the following error with the backtrace.
BUG: using smp_processor_id() in preemptible [00000000] code: \
kworker/7:3/1702
caller is refresh_cpu_vm_stats+0x235/0x5f0
CPU: 0 UID: 0 PID: 1702 Comm: kworker/7:3 Tainted: G
Tainted: [N]=TEST
Workqueue: mm_percpu_wq vmstat_update
Call Trace:
<TASK>
dump_stack_lvl+0x8d/0xb0
check_preemption_disabled+0xce/0xe0
refresh_cpu_vm_stats+0x235/0x5f0
vmstat_update+0x17/0xa0
process_one_work+0x869/0x1aa0
worker_thread+0x5e5/0x1100
kthread+0x29e/0x380
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
So, for mm/vmstat:online, disable vmstat_work reliably on teardown and
symmetrically enable it on startup.
Link: https://lkml.kernel.org/r/20241221033321.4154409-1-koichiro.den@canonical.com
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The 'shmem_falloc->nr_unswapped' is used to record how many writepage
refused to swap out because fallocate() is allocating, but after shmem
supports large folio swap out, the update of 'shmem_falloc->nr_unswapped'
does not use the correct number of pages in the large folio, which may
lead to fallocate() not exiting as soon as possible.
Anyway, this is found through code inspection, and I am not sure whether
it would actually cause serious issues.
Link: https://lkml.kernel.org/r/f66a0119d0564c2c37c84f045835b870d1b2196f.1734593154.git.baolin.wang@linux.alibaba.com
Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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With enabling the shmem per-size within_size policy, using an incorrect
'order' size to round_up() the index can lead to incorrect i_size checks,
resulting in an inappropriate large orders being returned.
Changing to use '1 << order' to round_up() the index to fix this issue.
Additionally, adding an 'aligned_index' variable to avoid affecting the
index checks.
Link: https://lkml.kernel.org/r/77d8ef76a7d3d646e9225e9af88a76549a68aab1.1734593154.git.baolin.wang@linux.alibaba.com
Fixes: e7a2ab7b3bb5 ("mm: shmem: add mTHP support for anonymous shmem")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the
current CPU at the beginning of the operation is retrieved and used
throughout. However, since neither preemption nor migration are disabled,
it is possible that the operation continues on a different CPU.
If the original CPU is hotunplugged while the acomp_ctx is still in use,
we run into a UAF bug as the resources attached to the acomp_ctx are freed
during hotunplug in zswap_cpu_comp_dead().
The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use
crypto_acomp API for hardware acceleration") when the switch to the
crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was
retrieved using get_cpu_ptr() which disables preemption and makes sure the
CPU cannot go away from under us. Preemption cannot be disabled with the
crypto_acomp API as a sleepable context is needed.
Commit 8ba2f844f050 ("mm/zswap: change per-cpu mutex and buffer to
per-acomp_ctx") increased the UAF surface area by making the per-CPU
buffers dynamic, adding yet another resource that can be freed from under
zswap compression/decompression by CPU hotunplug.
There are a few ways to fix this:
(a) Add a refcount for acomp_ctx.
(b) Disable migration while using the per-CPU acomp_ctx.
(c) Disable CPU hotunplug while using the per-CPU acomp_ctx by holding
the CPUs read lock.
Implement (c) since it's simpler than (a), and (b) involves using
migrate_disable() which is apparently undesired (see huge comment in
include/linux/preempt.h).
Link: https://lkml.kernel.org/r/20241219212437.2714151-1-yosryahmed@google.com
Fixes: 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Closes: https://lore.kernel.org/lkml/20241113213007.GB1564047@cmpxchg.org/
Reported-by: Sam Sun <samsun1006219@gmail.com>
Closes: https://lore.kernel.org/lkml/CAEkJfYMtSdM5HceNsXUDf5haghD5+o2e7Qv4OcuruL4tPg6OaQ@mail.gmail.com/
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Acked-by: Barry Song <baohua@kernel.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Address a bug in the kernel that triggers a "sleeping function called from
invalid context" warning when /sys/kernel/debug/kmemleak is printed under
specific conditions:
- CONFIG_PREEMPT_RT=y
- Set SELinux as the LSM for the system
- Set kptr_restrict to 1
- kmemleak buffer contains at least one item
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 136, name: cat
preempt_count: 1, expected: 0
RCU nest depth: 2, expected: 2
6 locks held by cat/136:
#0: ffff32e64bcbf950 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb8/0xe30
#1: ffffafe6aaa9dea0 (scan_mutex){+.+.}-{3:3}, at: kmemleak_seq_start+0x34/0x128
#3: ffff32e6546b1cd0 (&object->lock){....}-{2:2}, at: kmemleak_seq_show+0x3c/0x1e0
#4: ffffafe6aa8d8560 (rcu_read_lock){....}-{1:2}, at: has_ns_capability_noaudit+0x8/0x1b0
#5: ffffafe6aabbc0f8 (notif_lock){+.+.}-{2:2}, at: avc_compute_av+0xc4/0x3d0
irq event stamp: 136660
hardirqs last enabled at (136659): [<ffffafe6a80fd7a0>] _raw_spin_unlock_irqrestore+0xa8/0xd8
hardirqs last disabled at (136660): [<ffffafe6a80fd85c>] _raw_spin_lock_irqsave+0x8c/0xb0
softirqs last enabled at (0): [<ffffafe6a5d50b28>] copy_process+0x11d8/0x3df8
softirqs last disabled at (0): [<0000000000000000>] 0x0
Preemption disabled at:
[<ffffafe6a6598a4c>] kmemleak_seq_show+0x3c/0x1e0
CPU: 1 UID: 0 PID: 136 Comm: cat Tainted: G E 6.11.0-rt7+ #34
Tainted: [E]=UNSIGNED_MODULE
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0xa0/0x128
show_stack+0x1c/0x30
dump_stack_lvl+0xe8/0x198
dump_stack+0x18/0x20
rt_spin_lock+0x8c/0x1a8
avc_perm_nonode+0xa0/0x150
cred_has_capability.isra.0+0x118/0x218
selinux_capable+0x50/0x80
security_capable+0x7c/0xd0
has_ns_capability_noaudit+0x94/0x1b0
has_capability_noaudit+0x20/0x30
restricted_pointer+0x21c/0x4b0
pointer+0x298/0x760
vsnprintf+0x330/0xf70
seq_printf+0x178/0x218
print_unreferenced+0x1a4/0x2d0
kmemleak_seq_show+0xd0/0x1e0
seq_read_iter+0x354/0xe30
seq_read+0x250/0x378
full_proxy_read+0xd8/0x148
vfs_read+0x190/0x918
ksys_read+0xf0/0x1e0
__arm64_sys_read+0x70/0xa8
invoke_syscall.constprop.0+0xd4/0x1d8
el0_svc+0x50/0x158
el0t_64_sync+0x17c/0x180
%pS and %pK, in the same back trace line, are redundant, and %pS can void
%pK service in certain contexts.
%pS alone already provides the necessary information, and if it cannot
resolve the symbol, it falls back to printing the raw address voiding
the original intent behind the %pK.
Additionally, %pK requires a privilege check CAP_SYSLOG enforced through
the LSM, which can trigger a "sleeping function called from invalid
context" warning under RT_PREEMPT kernels when the check occurs in an
atomic context. This issue may also affect other LSMs.
This change avoids the unnecessary privilege check and resolves the
sleeping function warning without any loss of information.
Link: https://lkml.kernel.org/r/20241217142032.55793-1-acarmina@redhat.com
Fixes: 3a6f33d86baa ("mm/kmemleak: use %pK to display kernel pointers in backtrace")
Signed-off-by: Alessandro Carminati <acarmina@redhat.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Clément Léger <clement.leger@bootlin.com>
Cc: Alessandro Carminati <acarmina@redhat.com>
Cc: Eric Chanudet <echanude@redhat.com>
Cc: Gabriele Paoloni <gpaoloni@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The folio refcount may be increased unexpectly through try_get_folio() by
caller such as split_huge_pages. In huge_pmd_unshare(), we use refcount
to check whether a pmd page table is shared. The check is incorrect if
the refcount is increased by the above caller, and this can cause the page
table leaked:
BUG: Bad page state in process sh pfn:109324
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x66 pfn:0x109324
flags: 0x17ffff800000000(node=0|zone=2|lastcpupid=0xfffff)
page_type: f2(table)
raw: 017ffff800000000 0000000000000000 0000000000000000 0000000000000000
raw: 0000000000000066 0000000000000000 00000000f2000000 0000000000000000
page dumped because: nonzero mapcount
...
CPU: 31 UID: 0 PID: 7515 Comm: sh Kdump: loaded Tainted: G B 6.13.0-rc2master+ #7
Tainted: [B]=BAD_PAGE
Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
Call trace:
show_stack+0x20/0x38 (C)
dump_stack_lvl+0x80/0xf8
dump_stack+0x18/0x28
bad_page+0x8c/0x130
free_page_is_bad_report+0xa4/0xb0
free_unref_page+0x3cc/0x620
__folio_put+0xf4/0x158
split_huge_pages_all+0x1e0/0x3e8
split_huge_pages_write+0x25c/0x2d8
full_proxy_write+0x64/0xd8
vfs_write+0xcc/0x280
ksys_write+0x70/0x110
__arm64_sys_write+0x24/0x38
invoke_syscall+0x50/0x120
el0_svc_common.constprop.0+0xc8/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x34/0x128
el0t_64_sync_handler+0xc8/0xd0
el0t_64_sync+0x190/0x198
The issue may be triggered by damon, offline_page, page_idle, etc, which
will increase the refcount of page table.
1. The page table itself will be discarded after reporting the
"nonzero mapcount".
2. The HugeTLB page mapped by the page table miss freeing since we
treat the page table as shared and a shared page table will not be
unmapped.
Fix it by introducing independent PMD page table shared count. As
described by comment, pt_index/pt_mm/pt_frag_refcount are used for s390
gmap, x86 pgds and powerpc, pt_share_count is used for x86/arm64/riscv
pmds, so we can reuse the field as pt_share_count.
Link: https://lkml.kernel.org/r/20241216071147.3984217-1-liushixin2@huawei.com
Fixes: 39dde65c9940 ("[PATCH] shared page table for hugetlb page")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Ken Chen <kenneth.w.chen@intel.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When testing large folio support with XFS on our servers, we observed that
only a few large folios are mapped when reading large files via mmap.
After a thorough analysis, I identified it was caused by the
`/sys/block/*/queue/read_ahead_kb` setting. On our test servers, this
parameter is set to 128KB. After I tune it to 2MB, the large folio can
work as expected. However, I believe the large folio behavior should not
be dependent on the value of read_ahead_kb. It would be more robust if
the kernel can automatically adopt to it.
With /sys/block/*/queue/read_ahead_kb set to 128KB and performing a
sequential read on a 1GB file using MADV_HUGEPAGE, the differences in
/proc/meminfo are as follows:
- before this patch
FileHugePages: 18432 kB
FilePmdMapped: 4096 kB
- after this patch
FileHugePages: 1067008 kB
FilePmdMapped: 1048576 kB
This shows that after applying the patch, the entire 1GB file is mapped to
huge pages. The stable list is CCed, as without this patch, large folios
don't function optimally in the readahead path.
It's worth noting that if read_ahead_kb is set to a larger value that
isn't aligned with huge page sizes (e.g., 4MB + 128KB), it may still fail
to map to hugepages.
Link: https://lkml.kernel.org/r/20241108141710.9721-1-laoar.shao@gmail.com
Link: https://lkml.kernel.org/r/20241206083025.3478-1-laoar.shao@gmail.com
Fixes: 4687fdbb805a ("mm/filemap: Support VM_HUGEPAGE for file mappings")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Tested-by: kernel test robot <oliver.sang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit ed48e87c7df3 ("thp: add thp_get_unmapped_area_vmflags()") changes
thp_get_unmapped_area() to thp_get_unmapped_area_vmflags() in
__get_unmapped_area(), which doesn't initialize local get_area for
anonymous mappings. This leads to us always trying THP alignment even for
file_operations which have a NULL ->get_unmapped_area() callback.
Since commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP
boundaries") we only want to enable THP alignment for anonymous mappings,
so add a !file check to avoid attempting THP alignment for file mappings.
Found issue by code inspection. THP alignment is used for easy or more
pmd mappings, from vma side. This may cause unnecessary VMA fragmentation
and potentially worse performance on filesystems that do not actually
support THPs and thus cannot benefit from the alignment.
Link: https://lkml.kernel.org/r/20241206070345.2526501-1-wangkefeng.wang@huawei.com
Fixes: ed48e87c7df3 ("thp: add thp_get_unmapped_area_vmflags()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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throttle_direct_reclaim()
The task sometimes continues looping in throttle_direct_reclaim() because
allow_direct_reclaim(pgdat) keeps returning false.
#0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac
#1 [ffff80002cb6f900] __schedule at ffff800008abbd1c
#2 [ffff80002cb6f990] schedule at ffff800008abc50c
#3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550
#4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68
#5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660
#6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98
#7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8
#8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974
#9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4
At this point, the pgdat contains the following two zones:
NODE: 4 ZONE: 0 ADDR: ffff00817fffe540 NAME: "DMA32"
SIZE: 20480 MIN/LOW/HIGH: 11/28/45
VM_STAT:
NR_FREE_PAGES: 359
NR_ZONE_INACTIVE_ANON: 18813
NR_ZONE_ACTIVE_ANON: 0
NR_ZONE_INACTIVE_FILE: 50
NR_ZONE_ACTIVE_FILE: 0
NR_ZONE_UNEVICTABLE: 0
NR_ZONE_WRITE_PENDING: 0
NR_MLOCK: 0
NR_BOUNCE: 0
NR_ZSPAGES: 0
NR_FREE_CMA_PAGES: 0
NODE: 4 ZONE: 1 ADDR: ffff00817fffec00 NAME: "Normal"
SIZE: 8454144 PRESENT: 98304 MIN/LOW/HIGH: 68/166/264
VM_STAT:
NR_FREE_PAGES: 146
NR_ZONE_INACTIVE_ANON: 94668
NR_ZONE_ACTIVE_ANON: 3
NR_ZONE_INACTIVE_FILE: 735
NR_ZONE_ACTIVE_FILE: 78
NR_ZONE_UNEVICTABLE: 0
NR_ZONE_WRITE_PENDING: 0
NR_MLOCK: 0
NR_BOUNCE: 0
NR_ZSPAGES: 0
NR_FREE_CMA_PAGES: 0
In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of
inactive/active file-backed pages calculated in zone_reclaimable_pages()
based on the result of zone_page_state_snapshot() is zero.
Additionally, since this system lacks swap, the calculation of inactive/
active anonymous pages is skipped.
crash> p nr_swap_pages
nr_swap_pages = $1937 = {
counter = 0
}
As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to
the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having
free pages significantly exceeding the high watermark.
The problem is that the pgdat->kswapd_failures hasn't been incremented.
crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures
$1935 = 0x0
This is because the node deemed balanced. The node balancing logic in
balance_pgdat() evaluates all zones collectively. If one or more zones
(e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the
entire node is deemed balanced. This causes balance_pgdat() to exit early
before incrementing the kswapd_failures, as it considers the overall
memory state acceptable, even though some zones (like ZONE_NORMAL) remain
under significant pressure.
The patch ensures that zone_reclaimable_pages() includes free pages
(NR_FREE_PAGES) in its calculation when no other reclaimable pages are
available (e.g., file-backed or anonymous pages). This change prevents
zones like ZONE_DMA32, which have sufficient free pages, from being
mistakenly deemed unreclaimable. By doing so, the patch ensures proper
node balancing, avoids masking pressure on other zones like ZONE_NORMAL,
and prevents infinite loops in throttle_direct_reclaim() caused by
allow_direct_reclaim(pgdat) repeatedly returning false.
The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused
by a node being incorrectly deemed balanced despite pressure in certain
zones, such as ZONE_NORMAL. This issue arises from
zone_reclaimable_pages() returning 0 for zones without reclaimable file-
backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient
free pages to be skipped.
The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored
during reclaim, masking pressure in other zones. Consequently,
pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback
mechanisms in allow_direct_reclaim() from being triggered, leading to an
infinite loop in throttle_direct_reclaim().
This patch modifies zone_reclaimable_pages() to account for free pages
(NR_FREE_PAGES) when no other reclaimable pages exist. This ensures zones
with sufficient free pages are not skipped, enabling proper balancing and
reclaim behavior.
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20241130164346.436469-1-snishika@redhat.com
Link: https://lkml.kernel.org/r/20241130161236.433747-2-snishika@redhat.com
Fixes: 5a1c84b404a7 ("mm: remove reclaim and compaction retry approximations")
Signed-off-by: Seiji Nishikawa <snishika@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm: reinstate ability to map write-sealed memfd mappings
read-only".
In commit 158978945f31 ("mm: perform the mapping_map_writable() check
after call_mmap()") (and preceding changes in the same series) it became
possible to mmap() F_SEAL_WRITE sealed memfd mappings read-only.
Commit 5de195060b2e ("mm: resolve faulty mmap_region() error path
behaviour") unintentionally undid this logic by moving the
mapping_map_writable() check before the shmem_mmap() hook is invoked,
thereby regressing this change.
This series reworks how we both permit write-sealed mappings being mapped
read-only and disallow mprotect() from undoing the write-seal, fixing this
regression.
We also add a regression test to ensure that we do not accidentally
regress this in future.
Thanks to Julian Orth for reporting this regression.
This patch (of 2):
In commit 158978945f31 ("mm: perform the mapping_map_writable() check
after call_mmap()") (and preceding changes in the same series) it became
possible to mmap() F_SEAL_WRITE sealed memfd mappings read-only.
This was previously unnecessarily disallowed, despite the man page
documentation indicating that it would be, thereby limiting the usefulness
of F_SEAL_WRITE logic.
We fixed this by adapting logic that existed for the F_SEAL_FUTURE_WRITE
seal (one which disallows future writes to the memfd) to also be used for
F_SEAL_WRITE.
For background - the F_SEAL_FUTURE_WRITE seal clears VM_MAYWRITE for a
read-only mapping to disallow mprotect() from overriding the seal - an
operation performed by seal_check_write(), invoked from shmem_mmap(), the
f_op->mmap() hook used by shmem mappings.
By extending this to F_SEAL_WRITE and critically - checking
mapping_map_writable() to determine if we may map the memfd AFTER we
invoke shmem_mmap() - the desired logic becomes possible. This is because
mapping_map_writable() explicitly checks for VM_MAYWRITE, which we will
have cleared.
Commit 5de195060b2e ("mm: resolve faulty mmap_region() error path
behaviour") unintentionally undid this logic by moving the
mapping_map_writable() check before the shmem_mmap() hook is invoked,
thereby regressing this change.
We reinstate this functionality by moving the check out of shmem_mmap()
and instead performing it in do_mmap() at the point at which VMA flags are
being determined, which seems in any case to be a more appropriate place
in which to make this determination.
In order to achieve this we rework memfd seal logic to allow us access to
this information using existing logic and eliminate the clearing of
VM_MAYWRITE from seal_check_write() which we are performing in do_mmap()
instead.
Link: https://lkml.kernel.org/r/99fc35d2c62bd2e05571cf60d9f8b843c56069e0.1732804776.git.lorenzo.stoakes@oracle.com
Fixes: 5de195060b2e ("mm: resolve faulty mmap_region() error path behaviour")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: Julian Orth <ju.orth@gmail.com>
Closes: https://lore.kernel.org/all/CAHijbEUMhvJTN9Xw1GmbM266FXXv=U7s4L_Jem5x3AaPZxrYpQ@mail.gmail.com/
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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split_huge_pages_write() does not handle the case where strsep finds no
delimiter in the given string and sets the input buffer to NULL, which
allows this reproducer to trigger a protection fault.
Link: https://lkml.kernel.org/r/20241216042752.257090-2-leocstone@gmail.com
Signed-off-by: Leo Stone <leocstone@gmail.com>
Reported-by: syzbot+8a3da2f1bbf59227c289@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=8a3da2f1bbf59227c289
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Other page flags in the 2nd page, like PG_hwpoison and PG_anon_exclusive
can get modified concurrently. Changes to other page flags might be lost
if they are happening at the same time as non-atomic partially_mapped
operations. Hence, make partially_mapped operations atomic.
Link: https://lkml.kernel.org/r/20241212183351.1345389-1-usamaarif642@gmail.com
Fixes: 8422acdc97ed ("mm: introduce a pageflag for partially mapped folios")
Reported-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/all/e53b04ad-1827-43a2-a1ab-864c7efecf6e@redhat.com/
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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If the caller of vmap() specifies VM_MAP_PUT_PAGES (currently only the
i915 driver), we will decrement nr_vmalloc_pages and MEMCG_VMALLOC in
vfree(). These counters are incremented by vmalloc() but not by vmap() so
this will cause an underflow. Check the VM_MAP_PUT_PAGES flag before
decrementing either counter.
Link: https://lkml.kernel.org/r/20241211202538.168311-1-willy@infradead.org
Fixes: b944afc9d64d ("mm: add a VM_MAP_PUT_PAGES flag for vmap")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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split_large_buddy()
In split_large_buddy(), we might call pfn_to_page() on a PFN that might
not exist. In corner cases, such as when freeing the highest pageblock in
the last memory section, this could result with CONFIG_SPARSEMEM &&
!CONFIG_SPARSEMEM_EXTREME in __pfn_to_section() returning NULL and and
__section_mem_map_addr() dereferencing that NULL pointer.
Let's fix it, and avoid doing a pfn_to_page() call for the first
iteration, where we already have the page.
So far this was found by code inspection, but let's just CC stable as the
fix is easy.
Link: https://lkml.kernel.org/r/20241210093437.174413-1-david@redhat.com
Fixes: fd919a85cd55 ("mm: page_isolation: prepare for hygienic freelists")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Closes: https://lkml.kernel.org/r/e1a898ba-a717-4d20-9144-29df1a6c8813@suse.cz
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Some architectures have special handling after clearing user folios:
architectures, which set cpu_dcache_is_aliasing() to true, require
flushing dcache; arc, which sets cpu_icache_is_aliasing() to true, changes
folio->flags to make icache coherent to dcache. So __GFP_ZERO using only
clear_page() is not enough to zero user folios and clear_user_(high)page()
must be used. Otherwise, user data will be corrupted.
Fix it by always clearing user folios with clear_user_(high)page() when
cpu_dcache_is_aliasing() is true or cpu_icache_is_aliasing() is true.
Rename alloc_zeroed() to user_alloc_needs_zeroing() and invert the logic
to clarify its intend.
Link: https://lkml.kernel.org/r/20241209182326.2955963-2-ziy@nvidia.com
Fixes: 5708d96da20b ("mm: avoid zeroing user movable page twice with init_on_alloc=1")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Closes: https://lore.kernel.org/linux-mm/CAMuHMdV1hRp_NtR5YnJo=HsfgKQeH91J537Gh4gKk3PFZhSkbA@mail.gmail.com/
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Potapenko <glider@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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RCU lock is taken by ___pte_offset_map() unless it returns NULL. Add this
information to its inline callers to avoid sparse warning about context
imbalance in pte_unmap().
Link: https://lkml.kernel.org/r/20241210000604.700710-1-oss@malat.biz
Signed-off-by: Petr Malat <oss@malat.biz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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On second merge attempt on mmap() we incorrectly discard the possibly
merged VMA, resulting in a possible use-after-free (and most certainly a
reference to the wrong VMA) in this instance in the subsequent
__mmap_complete() invocation.
Correct this mistake by reassigning vma correctly if a merge succeeds in
this case.
Link: https://lkml.kernel.org/r/20241206215229.244413-1-lorenzo.stoakes@oracle.com
Fixes: 5ac87a885aec ("mm: defer second attempt at merge on mmap()")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Suggested-by: Jann Horn <jannh@google.com>
Reported-by: syzbot+91cf8da9401355f946c3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67536a25.050a0220.a30f1.0149.GAE@google.com/
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In current kernel, hugetlb_wp() calls copy_user_large_folio() with the
fault address. Where the fault address may be not aligned with the huge
page size. Then, copy_user_large_folio() may call
copy_user_gigantic_page() with the address, while
copy_user_gigantic_page() requires the address to be huge page size
aligned. So, this may cause memory corruption or information leak,
addtional, use more obvious naming 'addr_hint' instead of 'addr' for
copy_user_gigantic_page().
Link: https://lkml.kernel.org/r/20241028145656.932941-2-wangkefeng.wang@huawei.com
Fixes: 530dd9926dc1 ("mm: memory: improve copy_user_large_folio()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In current kernel, hugetlb_no_page() calls folio_zero_user() with the
fault address. Where the fault address may be not aligned with the huge
page size. Then, folio_zero_user() may call clear_gigantic_page() with
the address, while clear_gigantic_page() requires the address to be huge
page size aligned. So, this may cause memory corruption or information
leak, addtional, use more obvious naming 'addr_hint' instead of 'addr' for
clear_gigantic_page().
Link: https://lkml.kernel.org/r/20241028145656.932941-1-wangkefeng.wang@huawei.com
Fixes: 78fefd04c123 ("mm: memory: convert clear_huge_page() to folio_zero_user()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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/proc/meminfo ShmemHugePages has been showing overlarge amounts (more than
Shmem) after swapping out THPs: we forgot to update NR_SHMEM_THPS.
Add shmem_update_stats(), to avoid repetition, and risk of making that
mistake again: the call from shmem_delete_from_page_cache() is the bugfix;
the call from shmem_replace_folio() is reassuring, but not really a bugfix
(replace corrects misplaced swapin readahead, but huge swapin readahead
would be a mistake).
Link: https://lkml.kernel.org/r/5ba477c8-a569-70b5-923e-09ab221af45b@google.com
Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab fix from Vlastimil Babka:
- Fix for memcg unreclaimable slab stats drift when post-charging large
kmalloc allocations (Shakeel Butt)
* tag 'slab-for-6.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
memcg: slub: fix SUnreclaim for post charged objects
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Large kmalloc directly allocates from the page allocator and then use
lruvec_stat_mod_folio() to increment the unreclaimable slab stats for
global and memcg. However when post memcg charging of slab objects was
added in commit 9028cdeb38e1 ("memcg: add charging of already allocated
slab objects"), it missed to correctly handle the unreclaimable slab
stats for memcg.
One user visisble effect of that bug is that the node level
unreclaimable slab stat will work correctly but the memcg level stat can
underflow as kernel correctly handles the free path but the charge path
missed to increment the memcg level unreclaimable slab stat. Let's fix
by correctly handle in the post charge code path.
Fixes: 9028cdeb38e1 ("memcg: add charging of already allocated slab objects")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"24 hotfixes. 17 are cc:stable. 15 are MM and 9 are non-MM.
The usual bunch of singletons - please see the relevant changelogs for
details"
* tag 'mm-hotfixes-stable-2024-12-07-22-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (24 commits)
iio: magnetometer: yas530: use signed integer type for clamp limits
sched/numa: fix memory leak due to the overwritten vma->numab_state
mm/damon: fix order of arguments in damos_before_apply tracepoint
lib: stackinit: hide never-taken branch from compiler
mm/filemap: don't call folio_test_locked() without a reference in next_uptodate_folio()
scatterlist: fix incorrect func name in kernel-doc
mm: correct typo in MMAP_STATE() macro
mm: respect mmap hint address when aligning for THP
mm: memcg: declare do_memsw_account inline
mm/codetag: swap tags when migrate pages
ocfs2: update seq_file index in ocfs2_dlm_seq_next
stackdepot: fix stack_depot_save_flags() in NMI context
mm: open-code page_folio() in dump_page()
mm: open-code PageTail in folio_flags() and const_folio_flags()
mm: fix vrealloc()'s KASAN poisoning logic
Revert "readahead: properly shorten readahead when falling back to do_page_cache_ra()"
selftests/damon: add _damon_sysfs.py to TEST_FILES
selftest: hugetlb_dio: fix test naming
ocfs2: free inode when ocfs2_get_init_inode() fails
nilfs2: fix potential out-of-bounds memory access in nilfs_find_entry()
...
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next_uptodate_folio()
The folio can get freed + buddy-merged + reallocated in the meantime,
resulting in us calling folio_test_locked() possibly on a tail page.
This makes const_folio_flags VM_BUG_ON_PGFLAGS() when stumbling over the
tail page.
Could this result in other issues? Doesn't look like it. False positives
and false negatives don't really matter, because this folio would get
skipped either way when detecting that they have been reallocated in the
meantime.
Fix it by performing the folio_test_locked() checked after grabbing a
reference. If this ever becomes a real problem, we could add a special
helper that racily checks if the bit is set even on tail pages ... but
let's hope that's not required so we can just handle it cleaner: work on
the folio after we hold a reference.
Do we really need the folio_test_locked() check if we are going to trylock
briefly after? Well, we can at least avoid a xas_reload().
It's a bit unclear which exact change introduced that issue. Likely, ever
since we made PG_locked obey to the PF_NO_TAIL policy it could have been
triggered in some way.
Link: https://lkml.kernel.org/r/20241129125303.4033164-1-david@redhat.com
Fixes: 48c935ad88f5 ("page-flags: define PG_locked behavior on compound pages")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: syzbot+9f9a7f73fb079b2387a6@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/674184c9.050a0220.1cc393.0001.GAE@google.com/
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Hillf Danton <hdanton@sina.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We mistakenly refer to len rather than len_ here. The only existing
caller passes len to the len_ parameter so this has no impact on the code,
but it is obviously incorrect to do this, so fix it.
Link: https://lkml.kernel.org/r/20241118175414.390827-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Jann Horn <jannh@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP
boundaries") updated __get_unmapped_area() to align the start address for
the VMA to a PMD boundary if CONFIG_TRANSPARENT_HUGEPAGE=y.
It does this by effectively looking up a region that is of size,
request_size + PMD_SIZE, and aligning up the start to a PMD boundary.
Commit 4ef9ad19e176 ("mm: huge_memory: don't force huge page alignment on
32 bit") opted out of this for 32bit due to regressions in mmap base
randomization.
Commit d4148aeab412 ("mm, mmap: limit THP alignment of anonymous mappings
to PMD-aligned sizes") restricted this to only mmap sizes that are
multiples of the PMD_SIZE due to reported regressions in some performance
benchmarks -- which seemed mostly due to the reduced spatial locality of
related mappings due to the forced PMD-alignment.
Another unintended side effect has emerged: When a user specifies an mmap
hint address, the THP alignment logic modifies the behavior, potentially
ignoring the hint even if a sufficiently large gap exists at the requested
hint location.
Example Scenario:
Consider the following simplified virtual address (VA) space:
...
0x200000-0x400000 --- VMA A
0x400000-0x600000 --- Hole
0x600000-0x800000 --- VMA B
...
A call to mmap() with hint=0x400000 and len=0x200000 behaves differently:
- Before THP alignment: The requested region (size 0x200000) fits into
the gap at 0x400000, so the hint is respected.
- After alignment: The logic searches for a region of size
0x400000 (len + PMD_SIZE) starting at 0x400000.
This search fails due to the mapping at 0x600000 (VMA B), and the hint
is ignored, falling back to arch_get_unmapped_area[_topdown]().
In general the hint is effectively ignored, if there is any existing
mapping in the below range:
[mmap_hint + mmap_size, mmap_hint + mmap_size + PMD_SIZE)
This changes the semantics of mmap hint; from ""Respect the hint if a
sufficiently large gap exists at the requested location" to "Respect the
hint only if an additional PMD-sized gap exists beyond the requested
size".
This has performance implications for allocators that allocate their heap
using mmap but try to keep it "as contiguous as possible" by using the end
of the exisiting heap as the address hint. With the new behavior it's
more likely to get a much less contiguous heap, adding extra fragmentation
and performance overhead.
To restore the expected behavior; don't use
thp_get_unmapped_area_vmflags() when the user provided a hint address, for
anonymous mappings.
Note: As Yang Shi pointed out: the issue still remains for filesystems
which are using thp_get_unmapped_area() for their get_unmapped_area() op.
It is unclear what worklaods will regress for if we ignore THP alignment
when the hint address is provided for such file backed mappings -- so this
fix will be handled separately.
Link: https://lkml.kernel.org/r/20241118214650.3667577-1-kaleshsingh@google.com
Fixes: efa7df3e3bb5 ("mm: align larger anonymous mappings on THP boundaries")
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hans Boehm <hboehm@google.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In commit 66d60c428b23 ("mm: memcg: move legacy memcg event code into
memcontrol-v1.c"), the static do_memsw_account() function was moved from a
.c file to a .h file. Unfortunately, the traditional inline keyword
wasn't added. If a file (e.g., a unit test) includes the .h file, but
doesn't refer to do_memsw_account(), it will get a warning like:
mm/memcontrol-v1.h:41:13: warning: unused function 'do_memsw_account' [-Wunused-function]
41 | static bool do_memsw_account(void)
| ^~~~~~~~~~~~~~~~
Link: https://lkml.kernel.org/r/20241128203959.726527-1-jsperbeck@google.com
Fixes: 66d60c428b23 ("mm: memcg: move legacy memcg event code into memcontrol-v1.c")
Signed-off-by: John Sperbeck <jsperbeck@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Current solution to adjust codetag references during page migration is
done in 3 steps:
1. sets the codetag reference of the old page as empty (not pointing
to any codetag);
2. subtracts counters of the new page to compensate for its own
allocation;
3. sets codetag reference of the new page to point to the codetag of
the old page.
This does not work if CONFIG_MEM_ALLOC_PROFILING_DEBUG=n because
set_codetag_empty() becomes NOOP. Instead, let's simply swap codetag
references so that the new page is referencing the old codetag and the old
page is referencing the new codetag. This way accounting stays valid and
the logic makes more sense.
Link: https://lkml.kernel.org/r/20241129025213.34836-1-00107082@163.com
Fixes: e0a955bf7f61 ("mm/codetag: add pgalloc_tag_copy()")
Signed-off-by: David Wang <00107082@163.com>
Closes: https://lore.kernel.org/lkml/20241124074318.399027-1-00107082@163.com/
Acked-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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page_folio() calls page_fixed_fake_head() which will misidentify this page
as being a fake head and load off the end of 'precise'. We may have a
pointer to a fake head, but that's OK because it contains the right
information for dump_page().
gcc-15 is smart enough to catch this with -Warray-bounds:
In function 'page_fixed_fake_head',
inlined from '_compound_head' at ../include/linux/page-flags.h:251:24,
inlined from '__dump_page' at ../mm/debug.c:123:11:
../include/asm-generic/rwonce.h:44:26: warning: array subscript 9 is outside
+array bounds of 'struct page[1]' [-Warray-bounds=]
Link: https://lkml.kernel.org/r/20241125201721.2963278-2-willy@infradead.org
Fixes: fae7d834c43c ("mm: add __dump_folio()")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When vrealloc() reuses already allocated vmap_area, we need to re-annotate
poisoned and unpoisoned portions of underlying memory according to the new
size.
This results in a KASAN splat recorded at [1]. A KASAN mis-reporting
issue where there is none.
Note, hard-coding KASAN_VMALLOC_PROT_NORMAL might not be exactly correct,
but KASAN flag logic is pretty involved and spread out throughout
__vmalloc_node_range_noprof(), so I'm using the bare minimum flag here and
leaving the rest to mm people to refactor this logic and reuse it here.
Link: https://lkml.kernel.org/r/20241126005206.3457974-1-andrii@kernel.org
Link: https://lore.kernel.org/bpf/67450f9b.050a0220.21d33d.0004.GAE@google.com/ [1]
Fixes: 3ddc2fefe6f3 ("mm: vmalloc: implement vrealloc()")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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