linux.git/mm/memory-failure.c, branch v6.17

mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory

2025-09-09T06:45:11+00:00

When I did memory failure tests, below panic occurs:

page dumped because: VM_BUG_ON_PAGE(PagePoisoned(page))
kernel BUG at include/linux/page-flags.h:616!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 3 PID: 720 Comm: bash Not tainted 6.10.0-rc1-00195-g148743902568 #40
RIP: 0010:unpoison_memory+0x2f3/0x590
RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246
RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8
RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0
RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb
R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000
R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe
FS:  00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0
Call Trace:
 
 unpoison_memory+0x2f3/0x590
 simple_attr_write_xsigned.constprop.0.isra.0+0xb3/0x110
 debugfs_attr_write+0x42/0x60
 full_proxy_write+0x5b/0x80
 vfs_write+0xd5/0x540
 ksys_write+0x64/0xe0
 do_syscall_64+0xb9/0x1d0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f08f0314887
RSP: 002b:00007ffece710078 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f08f0314887
RDX: 0000000000000009 RSI: 0000564787a30410 RDI: 0000000000000001
RBP: 0000564787a30410 R08: 000000000000fefe R09: 000000007fffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009
R13: 00007f08f041b780 R14: 00007f08f0417600 R15: 00007f08f0416a00
 
Modules linked in: hwpoison_inject
---[ end trace 0000000000000000 ]---
RIP: 0010:unpoison_memory+0x2f3/0x590
RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246
RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8
RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0
RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb
R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000
R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe
FS:  00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0
Kernel panic - not syncing: Fatal exception
Kernel Offset: 0x31c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
---[ end Kernel panic - not syncing: Fatal exception ]---

The root cause is that unpoison_memory() tries to check the PG_HWPoison
flags of an uninitialized page.  So VM_BUG_ON_PAGE(PagePoisoned(page)) is
triggered.  This can be reproduced by below steps:

1.Offline memory block:

 echo offline > /sys/devices/system/memory/memory12/state

2.Get offlined memory pfn:

 page-types -b n -rlN

3.Write pfn to unpoison-pfn

 echo  > /sys/kernel/debug/hwpoison/unpoison-pfn

This scenario can be identified by pfn_to_online_page() returning NULL. 
And ZONE_DEVICE pages are never expected, so we can simply fail if
pfn_to_online_page() == NULL to fix the bug.

Link: https://lkml.kernel.org/r/20250828024618.1744895-1-linmiaohe@huawei.com
Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online")
Signed-off-by: Miaohe Lin 
Suggested-by: David Hildenbrand 
Acked-by: David Hildenbrand 
Cc: Naoya Horiguchi 
Cc: 
Signed-off-by: Andrew Morton

mm/memory-failure: fix redundant updates for already poisoned pages

2025-09-04T00:10:38+00:00

Duplicate memory errors can be reported by multiple sources.

Passing an already poisoned page to action_result() causes issues:

* The amount of hardware corrupted memory is incorrectly updated.
* Per NUMA node MF stats are incorrectly updated.
* Redundant "already poisoned" messages are printed.

Avoid those issues by:

* Skipping hardware corrupted memory updates for already poisoned pages.
* Skipping per NUMA node MF stats updates for already poisoned pages.
* Dropping redundant "already poisoned" messages.

Make MF_MSG_ALREADY_POISONED consistent with other action_page_types and
make calls to action_result() consistent for already poisoned normal pages
and huge pages.

Link: https://lkml.kernel.org/r/aLCiHMy12Ck3ouwC@hpe.com
Fixes: b8b9488d50b7 ("mm/memory-failure: improve memory failure action_result messages")
Signed-off-by: Kyle Meyer 
Reviewed-by: Jiaqi Yan 
Acked-by: David Hildenbrand 
Reviewed-by: Jane Chu 
Acked-by: Miaohe Lin 
Cc: Borislav Betkov 
Cc: Kyle Meyer 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes 
Cc: "Luck, Tony" 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Naoya Horiguchi 
Cc: Oscar Salvador 
Cc: Russ Anderson 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: 
Signed-off-by: Andrew Morton

mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn

2025-08-19T23:35:56+00:00

When memory_failure() is called for a already hwpoisoned pfn,
kill_accessing_process() will be called to kill current task.  However, if
the vma of the accessing vaddr is VM_PFNMAP, walk_page_range() will skip
the vma in walk_page_test() and return 0.

Before commit aaf99ac2ceb7 ("mm/hwpoison: do not send SIGBUS to processes
with recovered clean pages"), kill_accessing_process() will return EFAULT.
For x86, the current task will be killed in kill_me_maybe().

However, after this commit, kill_accessing_process() simplies return 0,
that means UCE is handled properly, but it doesn't actually.  In such
case, the user task will trigger UCE infinitely.

To fix it, add .test_walk callback for hwpoison_walk_ops to scan all vmas.

Link: https://lkml.kernel.org/r/20250815073209.1984582-1-tujinjiang@huawei.com
Fixes: aaf99ac2ceb7 ("mm/hwpoison: do not send SIGBUS to processes with recovered clean pages")
Signed-off-by: Jinjiang Tu 
Acked-by: David Hildenbrand 
Acked-by: Miaohe Lin 
Reviewed-by: Jane Chu 
Cc: Kefeng Wang 
Cc: Naoya Horiguchi 
Cc: Oscar Salvador 
Cc: Shuai Xue 
Cc: Zi Yan 
Cc: 
Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-08-03-12-35' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-08-05T13:02:07+00:00

Pull more MM updates from Andrew Morton:
 "Significant patch series in this pull request:

   - "mseal cleanups" (Lorenzo Stoakes)

     Some mseal cleaning with no intended functional change.

   - "Optimizations for khugepaged" (David Hildenbrand)

     Improve khugepaged throughput by batching PTE operations for large
     folios. This gain is mainly for arm64.

   - "x86: enable EXECMEM_ROX_CACHE for ftrace and kprobes" (Mike Rapoport)

     A bugfix, additional debug code and cleanups to the execmem code.

   - "mm/shmem, swap: bugfix and improvement of mTHP swap in" (Kairui Song)

     Bugfixes, cleanups and performance improvememnts to the mTHP swapin
     code"

* tag 'mm-stable-2025-08-03-12-35' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (38 commits)
  mm: mempool: fix crash in mempool_free() for zero-minimum pools
  mm: correct type for vmalloc vm_flags fields
  mm/shmem, swap: fix major fault counting
  mm/shmem, swap: rework swap entry and index calculation for large swapin
  mm/shmem, swap: simplify swapin path and result handling
  mm/shmem, swap: never use swap cache and readahead for SWP_SYNCHRONOUS_IO
  mm/shmem, swap: tidy up swap entry splitting
  mm/shmem, swap: tidy up THP swapin checks
  mm/shmem, swap: avoid redundant Xarray lookup during swapin
  x86/ftrace: enable EXECMEM_ROX_CACHE for ftrace allocations
  x86/kprobes: enable EXECMEM_ROX_CACHE for kprobes allocations
  execmem: drop writable parameter from execmem_fill_trapping_insns()
  execmem: add fallback for failures in vmalloc(VM_ALLOW_HUGE_VMAP)
  execmem: move execmem_force_rw() and execmem_restore_rox() before use
  execmem: rework execmem_cache_free()
  execmem: introduce execmem_alloc_rw()
  execmem: drop unused execmem_update_copy()
  mm: fix a UAF when vma->mm is freed after vma->vm_refcnt got dropped
  mm/rmap: add anon_vma lifetime debug check
  mm: remove mm/io-mapping.c
  ...

mm/memory-failure: hold PTL in hwpoison_hugetlb_range

2025-08-02T19:06:10+00:00

Hold PTL in hwpoison_hugetlb_range() to avoid operating on stale page, as
hwpoison_pte_range() have done.

This change is not known to address any issues which users have
experienced.

Link: https://lkml.kernel.org/r/20250725033112.2690158-1-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu 
Acked-by: David Hildenbrand 
Cc: Andrei Vagin 
Cc: Andrii Nakryiko 
Cc: Baolin Wang 
Cc: Brahmajit Das 
Cc: Catalin Marinas 
Cc: Christophe Leroy 
Cc: David Rientjes 
Cc: Dev Jain 
Cc: Hugh Dickins 
Cc: Joern Engel 
Cc: Kefeng Wang 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Ryan Roberts 
Cc: Thiago Jung Bauermann 
Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-07-31T21:57:54+00:00

Pull MM updates from Andrew Morton:
 "As usual, many cleanups. The below blurbiage describes 42 patchsets.
  21 of those are partially or fully cleanup work. "cleans up",
  "cleanup", "maintainability", "rationalizes", etc.

  I never knew the MM code was so dirty.

  "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes)
     addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly
     mapped VMAs were not eligible for merging with existing adjacent
     VMAs.

  "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park)
     adds a new kernel module which simplifies the setup and usage of
     DAMON in production environments.

  "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig)
     is a cleanup to the writeback code which removes a couple of
     pointers from struct writeback_control.

  "drivers/base/node.c: optimization and cleanups" (Donet Tom)
     contains largely uncorrelated cleanups to the NUMA node setup and
     management code.

  "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman)
     does some maintenance work on the userfaultfd code.

  "Readahead tweaks for larger folios" (Ryan Roberts)
     implements some tuneups for pagecache readahead when it is reading
     into order>0 folios.

  "selftests/mm: Tweaks to the cow test" (Mark Brown)
     provides some cleanups and consistency improvements to the
     selftests code.

  "Optimize mremap() for large folios" (Dev Jain)
     does that. A 37% reduction in execution time was measured in a
     memset+mremap+munmap microbenchmark.

  "Remove zero_user()" (Matthew Wilcox)
     expunges zero_user() in favor of the more modern memzero_page().

  "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand)
     addresses some warts which David noticed in the huge page code.
     These were not known to be causing any issues at this time.

  "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park)
     provides some cleanup and consolidation work in DAMON.

  "use vm_flags_t consistently" (Lorenzo Stoakes)
     uses vm_flags_t in places where we were inappropriately using other
     types.

  "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy)
     increases the reliability of large page allocation in the memfd
     code.

  "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple)
     removes several now-unneeded PFN_* flags.

  "mm/damon: decouple sysfs from core" (SeongJae Park)
     implememnts some cleanup and maintainability work in the DAMON
     sysfs layer.

  "madvise cleanup" (Lorenzo Stoakes)
     does quite a lot of cleanup/maintenance work in the madvise() code.

  "madvise anon_name cleanups" (Vlastimil Babka)
     provides additional cleanups on top or Lorenzo's effort.

  "Implement numa node notifier" (Oscar Salvador)
     creates a standalone notifier for NUMA node memory state changes.
     Previously these were lumped under the more general memory
     on/offline notifier.

  "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan)
     cleans up the pageblock isolation code and fixes a potential issue
     which doesn't seem to cause any problems in practice.

  "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park)
     adds additional drgn- and python-based DAMON selftests which are
     more comprehensive than the existing selftest suite.

  "Misc rework on hugetlb faulting path" (Oscar Salvador)
     fixes a rather obscure deadlock in the hugetlb fault code and
     follows that fix with a series of cleanups.

  "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport)
     rationalizes and cleans up the highmem-specific code in the CMA
     allocator.

  "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand)
     provides cleanups and future-preparedness to the migration code.

  "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park)
     adds some tracepoints to some DAMON auto-tuning code.

  "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park)
     does that.

  "mm/damon: misc cleanups" (SeongJae Park)
     also does what it claims.

  "mm: folio_pte_batch() improvements" (David Hildenbrand)
     cleans up the large folio PTE batching code.

  "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park)
     facilitates dynamic alteration of DAMON's inter-node allocation
     policy.

  "Remove unmap_and_put_page()" (Vishal Moola)
     provides a couple of page->folio conversions.

  "mm: per-node proactive reclaim" (Davidlohr Bueso)
     implements a per-node control of proactive reclaim - beyond the
     current memcg-based implementation.

  "mm/damon: remove damon_callback" (SeongJae Park)
     replaces the damon_callback interface with a more general and
     powerful damon_call()+damos_walk() interface.

  "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes)
     implements a number of mremap cleanups (of course) in preparation
     for adding new mremap() functionality: newly permit the remapping
     of multiple VMAs when the user is specifying MREMAP_FIXED. It still
     excludes some specialized situations where this cannot be performed
     reliably.

  "drop hugetlb_free_pgd_range()" (Anthony Yznaga)
     switches some sparc hugetlb code over to the generic version and
     removes the thus-unneeded hugetlb_free_pgd_range().

  "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park)
     augments the present userspace-requested update of DAMON sysfs
     monitoring files. Automatic update is now provided, along with a
     tunable to control the update interval.

  "Some randome fixes and cleanups to swapfile" (Kemeng Shi)
     does what is claims.

  "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand)
     provides (and uses) a means by which debug-style functions can grab
     a copy of a pageframe and inspect it locklessly without tripping
     over the races inherent in operating on the live pageframe
     directly.

  "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan)
     addresses the large contention issues which can be triggered by
     reads from that procfs file. Latencies are reduced by more than
     half in some situations. The series also introduces several new
     selftests for the /proc/pid/maps interface.

  "__folio_split() clean up" (Zi Yan)
     cleans up __folio_split()!

  "Optimize mprotect() for large folios" (Dev Jain)
     provides some quite large (>3x) speedups to mprotect() when dealing
     with large folios.

  "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian)
     does some cleanup work in the selftests code.

  "tools/testing: expand mremap testing" (Lorenzo Stoakes)
     extends the mremap() selftest in several ways, including adding
     more checking of Lorenzo's recently added "permit mremap() move of
     multiple VMAs" feature.

  "selftests/damon/sysfs.py: test all parameters" (SeongJae Park)
     extends the DAMON sysfs interface selftest so that it tests all
     possible user-requested parameters. Rather than the present minimal
     subset"

* tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits)
  MAINTAINERS: add missing headers to mempory policy & migration section
  MAINTAINERS: add missing file to cgroup section
  MAINTAINERS: add MM MISC section, add missing files to MISC and CORE
  MAINTAINERS: add missing zsmalloc file
  MAINTAINERS: add missing files to page alloc section
  MAINTAINERS: add missing shrinker files
  MAINTAINERS: move memremap.[ch] to hotplug section
  MAINTAINERS: add missing mm_slot.h file THP section
  MAINTAINERS: add missing interval_tree.c to memory mapping section
  MAINTAINERS: add missing percpu-internal.h file to per-cpu section
  mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info()
  selftests/damon: introduce _common.sh to host shared function
  selftests/damon/sysfs.py: test runtime reduction of DAMON parameters
  selftests/damon/sysfs.py: test non-default parameters runtime commit
  selftests/damon/sysfs.py: generalize DAMON context commit assertion
  selftests/damon/sysfs.py: generalize monitoring attributes commit assertion
  selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion
  selftests/damon/sysfs.py: test DAMOS filters commitment
  selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion
  selftests/damon/sysfs.py: test DAMOS destinations commitment
  ...

Merge tag 'acpi-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2025-07-29T03:44:42+00:00

Pull ACPI updates from Rafael Wysocki:
 "These update APEI (new EINJv2 error injection, assorted fixes), fix
  the ACPI processor driver, update the legacy ACPI /proc interface
  (multiple assorted fixes of minor issues) and several assorted ACPI
  drivers (minor fixes and cleanups):

   - Printing the address in acpi_ex_trace_point() is either incorrect
     during early kernel boot or not really useful later when pathnames
     resolve properly, so stop doing it (Mario Limonciello)

   - Address several minor issues in the legacy ACPI proc interface
     (Andy Shevchenko)

   - Fix acpi_object union initialization in the ACPI processor driver
     to avoid using memory that contains leftover data (Sebastian Ott)

   - Make the ACPI processor perflib driver take the initial _PPC limit
     into account as appropriate (Jiayi Li)

   - Fix message formatting in the ACPI processor throttling driver and
     in the ACPI PCI link driver (Colin Ian King)

   - Clean up general ACPI PM domain handling (Rafael Wysocki)

   - Fix iomem-related sparse warnings in the APEI EINJ driver (Zaid
     Alali, Tony Luck)

   - Add EINJv2 error injection support to the APEI EINJ driver (Zaid
     Alali)

   - Fix memory corruption in error_type_set() in the APEI EINJ driver
     (Dan Carpenter)

   - Fix less than zero comparison on a size_t variable in the APEI EINJ
     driver (Colin Ian King)

   - Fix check and iounmap of an uninitialized pointer in the APEI EINJ
     driver (Colin Ian King)

   - Add TAINT_MACHINE_CHECK to the GHES panic path in APEI to improve
     diagnostics and post-mortem analysis (Breno Leitao)

   - Update APEI reviewer records and other ACPI-related information in
     MAINTAINERS as well as the contact information in the ACPI ABI
     documentation (Rafael Wysocki)

   - Fix the handling of synchronous uncorrected memory errors in APEI
     (Shuai Xue)

   - Remove an AudioDSP-related ID from the ACPI LPSS driver (Andy
     Shevchenko)

   - Replace sprintf()/scnprintf() with sysfs_emit() in the ACPI fan
     driver and update a debug message in fan_get_state_acpi4() (Eslam
     Khafagy, Abdelrahman Fekry, Sumeet Pawnikar)

   - Add Intel Wildcat Lake support to the ACPI DPTF driver (Srinivas
     Pandruvada)

   - Add more debug information regarding failing firmware updates to
     the ACPI pfr_update driver (Chen Yu)

   - Reduce the verbosity of the ACPI PRM (platform runtime mechanism)
     driver to avoid user confusion (Zhu Qiyu)

   - Replace sprintf() with sysfs_emit() in the ACPI TAD (time and alarm
     device) driver (Sukrut Heroorkar)

   - Enable CONFIG_ACPI_DEBUG by default to make it easier to get ACPI
     debug messages from OEM platforms (Mario Limonciello)

   - Fix parent device references in ASL examples in the ACPI
     documentation and fix spelling and style in the gpio-properties
     documentation in firmware-guide (Andy Shevchenko)

   - Fix typos in ACPI documentation and comments (Bjorn Helgaas)"

* tag 'acpi-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (39 commits)
  ACPI: Fix typos
  ACPI/PCI: Remove space before newline
  ACPI: processor: throttling: Remove space before newline
  ACPI: processor: perflib: Fix initial _PPC limit application
  ACPI/PNP: Use my kernel.org address in MAINTAINERS and ABI docs
  ACPI: TAD: Replace sprintf() with sysfs_emit()
  ACPI: APEI: handle synchronous exceptions in task work
  ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered
  ACPI: APEI: MAINTAINERS: Update reviewers for APEI
  Documentation: ACPI: Fix parent device references
  ACPI: fan: Update debug message in fan_get_state_acpi4()
  ACPI: PRM: Reduce unnecessary printing to avoid user confusion
  ACPI: fan: Replace sprintf() with sysfs_emit()
  ACPI: APEI: EINJ: Fix trigger actions
  ACPI: processor: fix acpi_object initialization
  ACPI: APEI: GHES: add TAINT_MACHINE_CHECK on GHES panic path
  ACPI: LPSS: Remove AudioDSP related ID
  Documentation: firmware-guide: gpio-properties: Spelling and style fixes
  ACPI: fan: Replace sprintf()/scnprintf() with sysfs_emit() in show() functions
  ACPI: PM: Set .detach in acpi_general_pm_domain definition
  ...

mm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list

2025-07-20T02:26:15+00:00

In shrink_folio_list(), the hwpoisoned folio may be large folio, which
can't be handled by unmap_poisoned_folio().  For THP, try_to_unmap_one()
must be passed with TTU_SPLIT_HUGE_PMD to split huge PMD first and then
retry.  Without TTU_SPLIT_HUGE_PMD, we will trigger null-ptr deref of
pvmw.pte.  Even we passed TTU_SPLIT_HUGE_PMD, we will trigger a
WARN_ON_ONCE due to the page isn't in swapcache.

Since UCE is rare in real world, and race with reclaimation is more rare,
just skipping the hwpoisoned large folio is enough.  memory_failure() will
handle it if the UCE is triggered again.

This happens when memory reclaim for large folio races with
memory_failure(), and will lead to kernel panic.  The race is as
follows:

cpu0      cpu1
 shrink_folio_list memory_failure
  TestSetPageHWPoison
  unmap_poisoned_folio
  --> trigger BUG_ON due to
  unmap_poisoned_folio couldn't
   handle large folio

[tujinjiang@huawei.com: add comment to unmap_poisoned_folio()]
  Link: https://lkml.kernel.org/r/69fd4e00-1b13-d5f7-1c82-705c7d977ea4@huawei.com
Link: https://lkml.kernel.org/r/20250627125747.3094074-2-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu 
Fixes: 1b0449544c64 ("mm/vmscan: don't try to reclaim hwpoison folio")
Reported-by: syzbot+3b220254df55d8ca8a61@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68412d57.050a0220.2461cf.000e.GAE@google.com/
Acked-by: David Hildenbrand 
Reviewed-by: Miaohe Lin 
Acked-by: Zi Yan 
Reviewed-by: Oscar Salvador 
Cc: Kefeng Wang 
Cc: Michal Hocko 
Cc: Oscar Salvador 
Cc: 
Signed-off-by: Andrew Morton

ACPI: APEI: handle synchronous exceptions in task work

2025-07-16T19:08:04+00:00

The memory uncorrected error could be signaled by asynchronous interrupt
(specifically, SPI in arm64 platform), e.g. when an error is detected by
a background scrubber, or signaled by synchronous exception
(specifically, data abort exception in arm64 platform), e.g. when a CPU
tries to access a poisoned cache line. Currently, both synchronous and
asynchronous errors use memory_failure_queue() to schedule
memory_failure() to exectute in a kworker context.

As a result, when a user-space process is accessing a poisoned data, a
data abort is taken and the memory_failure() is executed in the kworker
context, which:

  - will send wrong si_code by SIGBUS signal in early_kill mode, and
  - can not kill the user-space in some cases resulting a synchronous
    error infinite loop

Issue 1: send wrong si_code in early_kill mode

Since commit a70297d22132 ("ACPI: APEI: set memory failure flags as
MF_ACTION_REQUIRED on synchronous events")', the flag MF_ACTION_REQUIRED
could be used to determine whether a synchronous exception occurs on
ARM64 platform.  When a synchronous exception is detected, the kernel is
expected to terminate the current process which has accessed a poisoned
page. This is done by sending a SIGBUS signal with error code
BUS_MCEERR_AR, indicating an action-required machine check error on
read.

However, when kill_proc() is called to terminate the processes who has
the poisoned page mapped, it sends the incorrect SIGBUS error code
BUS_MCEERR_AO because the context in which it operates is not the one
where the error was triggered.

To reproduce this problem:

  #sysctl -w vm.memory_failure_early_kill=1
  vm.memory_failure_early_kill = 1

  # STEP2: inject an UCE error and consume it to trigger a synchronous error
  #einj_mem_uc single
  0: single   vaddr = 0xffffb0d75400 paddr = 4092d55b400
  injecting ...
  triggering ...
  signal 7 code 5 addr 0xffffb0d75000
  page not present
  Test passed

The si_code (code 5) from einj_mem_uc indicates that it is BUS_MCEERR_AO
error and it is not factually correct.

After this change:

  # STEP1: enable early kill mode
  #sysctl -w vm.memory_failure_early_kill=1
  vm.memory_failure_early_kill = 1
  # STEP2: inject an UCE error and consume it to trigger a synchronous error
  #einj_mem_uc single
  0: single   vaddr = 0xffffb0d75400 paddr = 4092d55b400
  injecting ...
  triggering ...
  signal 7 code 4 addr 0xffffb0d75000
  page not present
  Test passed

The si_code (code 4) from einj_mem_uc indicates that it is a BUS_MCEERR_AR
error as expected.

Issue 2: a synchronous error infinite loop

If a user-space process, e.g. devmem, accesses a poisoned page for which
the HWPoison flag is set, kill_accessing_process() is called to send
SIGBUS to current processs with error info. Since the memory_failure()
is executed in the kworker context, it will just do nothing but return
EFAULT. So, devmem will access the posioned page and trigger an
exception again, resulting in a synchronous error infinite loop. Such
exception loop may cause platform firmware to exceed some threshold and
reboot when Linux could have recovered from this error.

To reproduce this problem:

  # STEP 1: inject an UCE error, and kernel will set HWPosion flag for related page
  #einj_mem_uc single
  0: single   vaddr = 0xffffb0d75400 paddr = 4092d55b400
  injecting ...
  triggering ...
  signal 7 code 4 addr 0xffffb0d75000
  page not present
  Test passed

  # STEP 2: access the same page and it will trigger a synchronous error infinite loop
  devmem 0x4092d55b400

To fix above two issues, queue memory_failure() as a task_work so that
it runs in the context of the process that is actually consuming the
poisoned data.

Signed-off-by: Shuai Xue 
Tested-by: Ma Wupeng 
Reviewed-by: Kefeng Wang 
Reviewed-by: Xiaofei Tan 
Reviewed-by: Baolin Wang 
Reviewed-by: Jarkko Sakkinen 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Jane Chu 
Reviewed-by: Yazen Ghannam 
Reviewed-by: Hanjun Guo 
Link: https://patch.msgid.link/20250714114212.31660-3-xueshuai@linux.alibaba.com
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki

mm: rename __PageMovable() to page_has_movable_ops()

2025-07-13T23:38:29+00:00

Let's make it clearer that we are talking about movable_ops pages.

While at it, convert a VM_BUG_ON to a VM_WARN_ON_ONCE_PAGE.

Link: https://lkml.kernel.org/r/20250704102524.326966-17-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Zi Yan 
Reviewed-by: Lorenzo Stoakes 
Reviewed-by: Harry Yoo 
Cc: Alistair Popple 
Cc: Al Viro 
Cc: Arnd Bergmann 
Cc: Brendan Jackman 
Cc: Byungchul Park 
Cc: Chengming Zhou 
Cc: Christian Brauner 
Cc: Christophe Leroy 
Cc: Eugenio Pé rez 
Cc: Greg Kroah-Hartman 
Cc: Gregory Price 
Cc: "Huang, Ying" 
Cc: Jan Kara 
Cc: Jason Gunthorpe 
Cc: Jason Wang 
Cc: Jerrin Shaji George 
Cc: Johannes Weiner 
Cc: John Hubbard 
Cc: Jonathan Corbet 
Cc: Joshua Hahn 
Cc: Liam Howlett 
Cc: Madhavan Srinivasan 
Cc: Mathew Brost 
Cc: Matthew Wilcox (Oracle) 
Cc: Miaohe Lin 
Cc: Michael Ellerman 
Cc: "Michael S. Tsirkin" 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Minchan Kim 
Cc: Naoya Horiguchi 
Cc: Nicholas Piggin 
Cc: Oscar Salvador 
Cc: Peter Xu 
Cc: Qi Zheng 
Cc: Rakie Kim 
Cc: Rik van Riel 
Cc: Sergey Senozhatsky 
Cc: Shakeel Butt 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: Xuan Zhuo 
Cc: xu xin 
Signed-off-by: Andrew Morton