linux.git/mm, branch v6.17-rc6

Merge tag 'mm-hotfixes-stable-2025-09-10-20-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-09-11T04:19:34+00:00

Pull misc fixes from Andrew Morton:
 "20 hotfixes. 15 are cc:stable and the remainder address post-6.16
  issues or aren't considered necessary for -stable kernels. 14 of these
  fixes are for MM.

  This includes

   - kexec fixes from Breno for a recently introduced
     use-uninitialized bug

   - DAMON fixes from Quanmin Yan to avoid div-by-zero crashes
     which can occur if the operator uses poorly-chosen insmod
     parameters

   and misc singleton fixes"

* tag 'mm-hotfixes-stable-2025-09-10-20-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  MAINTAINERS: add tree entry to numa memblocks and emulation block
  mm/damon/sysfs: fix use-after-free in state_show()
  proc: fix type confusion in pde_set_flags()
  compiler-clang.h: define __SANITIZE_*__ macros only when undefined
  mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc()
  ocfs2: fix recursive semaphore deadlock in fiemap call
  mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory
  mm/mremap: fix regression in vrm->new_addr check
  percpu: fix race on alloc failed warning limit
  mm/memory-failure: fix redundant updates for already poisoned pages
  s390: kexec: initialize kexec_buf struct
  riscv: kexec: initialize kexec_buf struct
  arm64: kexec: initialize kexec_buf struct in load_other_segments()
  mm/damon/reclaim: avoid divide-by-zero in damon_reclaim_apply_parameters()
  mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters()
  mm/damon/core: set quota->charged_from to jiffies at first charge window
  mm/hugetlb: add missing hugetlb_lock in __unmap_hugepage_range()
  init/main.c: fix boot time tracing crash
  mm/memory_hotplug: fix hwpoisoned large folio handling in do_migrate_range()
  mm/khugepaged: fix the address passed to notifier on testing young

mm/damon/sysfs: fix use-after-free in state_show()

2025-09-09T06:45:12+00:00

state_show() reads kdamond->damon_ctx without holding damon_sysfs_lock. 
This allows a use-after-free race:

CPU 0                         CPU 1
-----                         -----
state_show()                  damon_sysfs_turn_damon_on()
ctx = kdamond->damon_ctx;     mutex_lock(&damon_sysfs_lock);
                              damon_destroy_ctx(kdamond->damon_ctx);
                              kdamond->damon_ctx = NULL;
                              mutex_unlock(&damon_sysfs_lock);
damon_is_running(ctx);        /* ctx is freed */
mutex_lock(&ctx->kdamond_lock); /* UAF */

(The race can also occur with damon_sysfs_kdamonds_rm_dirs() and
damon_sysfs_kdamond_release(), which free or replace the context under
damon_sysfs_lock.)

Fix by taking damon_sysfs_lock before dereferencing the context, mirroring
the locking used in pid_show().

The bug has existed since state_show() first accessed kdamond->damon_ctx.

Link: https://lkml.kernel.org/r/20250905101046.2288-1-disclosure@aisle.com
Fixes: a61ea561c871 ("mm/damon/sysfs: link DAMON for virtual address spaces monitoring")
Signed-off-by: Stanislav Fort 
Reported-by: Stanislav Fort 
Reviewed-by: SeongJae Park 
Cc: 
Signed-off-by: Andrew Morton

mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc()

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

kasan_populate_vmalloc() and its helpers ignore the caller's gfp_mask and
always allocate memory using the hardcoded GFP_KERNEL flag.  This makes
them inconsistent with vmalloc(), which was recently extended to support
GFP_NOFS and GFP_NOIO allocations.

Page table allocations performed during shadow population also ignore the
external gfp_mask.  To preserve the intended semantics of GFP_NOFS and
GFP_NOIO, wrap the apply_to_page_range() calls into the appropriate
memalloc scope.

xfs calls vmalloc with GFP_NOFS, so this bug could lead to deadlock.

There was a report here
https://lkml.kernel.org/r/686ea951.050a0220.385921.0016.GAE@google.com

This patch:
 - Extends kasan_populate_vmalloc() and helpers to take gfp_mask;
 - Passes gfp_mask down to alloc_pages_bulk() and __get_free_page();
 - Enforces GFP_NOFS/NOIO semantics with memalloc_*_save()/restore()
   around apply_to_page_range();
 - Updates vmalloc.c and percpu allocator call sites accordingly.

Link: https://lkml.kernel.org/r/20250831121058.92971-1-urezki@gmail.com
Fixes: 451769ebb7e7 ("mm/vmalloc: alloc GFP_NO{FS,IO} for vmalloc")
Signed-off-by: Uladzislau Rezki (Sony) 
Reported-by: syzbot+3470c9ffee63e4abafeb@syzkaller.appspotmail.com
Reviewed-by: Andrey Ryabinin 
Cc: Baoquan He 
Cc: Michal Hocko 
Cc: Alexander Potapenko 
Cc: Andrey Konovalov 
Cc: Dmitry Vyukov 
Cc: Vincenzo Frascino 
Cc: 
Signed-off-by: Andrew Morton

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/mremap: fix regression in vrm->new_addr check

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

Commit 3215eaceca87 ("mm/mremap: refactor initial parameter sanity
checks") moved the sanity check for vrm->new_addr from mremap_to() to
check_mremap_params().

However, this caused a regression as vrm->new_addr is now checked even
when MREMAP_FIXED and MREMAP_DONTUNMAP flags are not specified.  In this
case, vrm->new_addr can be garbage and create unexpected failures.

Fix this by moving the new_addr check after the vrm_implies_new_addr()
guard.  This ensures that the new_addr is only checked when the user has
specified one explicitly.

Link: https://lkml.kernel.org/r/20250828142657.770502-1-cmllamas@google.com
Fixes: 3215eaceca87 ("mm/mremap: refactor initial parameter sanity checks")
Signed-off-by: Carlos Llamas 
Reviewed-by: Liam R. Howlett 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Lorenzo Stoakes 
Cc: Carlos Llamas 
Cc: Jann Horn 
Signed-off-by: Andrew Morton

percpu: fix race on alloc failed warning limit

2025-09-09T06:45:10+00:00

The 'allocation failed, ...' warning messages can cause unlimited log
spam, contrary to the implementation's intent.

The warn_limit variable is accessed without synchronization.  If more than
 threads enter the warning path at the same time, the variable
will get decremented past 0.  Once it becomes negative, the non-zero check
will always return true leading to unlimited log spam.

Use atomic operation to access warn_limit and change condition to test for
non-negative (>= 0) - atomic_dec_if_positive will return -1 once
warn_limit becomes 0.  Continue to print disable message alongside the
last warning.

While the change cited in Fixes is only adjacent, the warning limit
implementation was correct before it.  Only non-atomic allocations were
considered for warnings, and those happened to hold pcpu_alloc_mutex while
accessing warn_limit.

[vdumitrescu@nvidia.com: prevent warn_limit from going negative, per Christoph Lameter]
  Link: https://lkml.kernel.org/r/ee87cc59-2717-4dbb-8052-1d2692c5aaaa@nvidia.com
Link: https://lkml.kernel.org/r/ab22061a-a62f-4429-945b-744e5cc4ba35@nvidia.com
Fixes: f7d77dfc91f7 ("mm/percpu.c: print error message too if atomic alloc failed")
Signed-off-by: Vlad Dumitrescu 
Reviewed-by: Baoquan He 
Cc: Christoph Lameter (Ampere) 
Cc: Dennis Zhou 
Cc: Tejun Heo 
Signed-off-by: Andrew Morton

Merge tag 'slab-for-6.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

2025-09-04T16:54:20+00:00

Pull slab fixes from Vlastimil Babka:

 - Stable fix to make slub_debug code not access invalid pointers in the
   process of reporting issues (Li Qiong)

 - Stable fix to make object tracking pass gfp flags to stackdepot to
   avoid deadlock in contexts that can't even wake up kswapd due to e.g.
   timers debugging enabled (yangshiguang)

* tag 'slab-for-6.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  mm: slub: avoid wake up kswapd in set_track_prepare
  mm/slub: avoid accessing metadata when pointer is invalid in object_err()

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/damon/reclaim: avoid divide-by-zero in damon_reclaim_apply_parameters()

2025-09-04T00:10:37+00:00

When creating a new scheme of DAMON_RECLAIM, the calculation of
'min_age_region' uses 'aggr_interval' as the divisor, which may lead to
division-by-zero errors.  Fix it by directly returning -EINVAL when such a
case occurs.

Link: https://lkml.kernel.org/r/20250827115858.1186261-3-yanquanmin1@huawei.com
Fixes: f5a79d7c0c87 ("mm/damon: introduce struct damos_access_pattern")
Signed-off-by: Quanmin Yan 
Reviewed-by: SeongJae Park 
Cc: Kefeng Wang 
Cc: ze zuo 
Cc: 	[6.1+]
Signed-off-by: Andrew Morton

mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters()

2025-09-04T00:10:36+00:00

Patch series "mm/damon: avoid divide-by-zero in DAMON module's parameters
application".

DAMON's RECLAIM and LRU_SORT modules perform no validation on
user-configured parameters during application, which may lead to
division-by-zero errors.

Avoid the divide-by-zero by adding validation checks when DAMON modules
attempt to apply the parameters.


This patch (of 2):

During the calculation of 'hot_thres' and 'cold_thres', either
'sample_interval' or 'aggr_interval' is used as the divisor, which may
lead to division-by-zero errors.  Fix it by directly returning -EINVAL
when such a case occurs.  Additionally, since 'aggr_interval' is already
required to be set no smaller than 'sample_interval' in damon_set_attrs(),
only the case where 'sample_interval' is zero needs to be checked.

Link: https://lkml.kernel.org/r/20250827115858.1186261-2-yanquanmin1@huawei.com
Fixes: 40e983cca927 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Signed-off-by: Quanmin Yan 
Reviewed-by: SeongJae Park 
Cc: Kefeng Wang 
Cc: ze zuo 
Cc: 	[6.0+]
Signed-off-by: Andrew Morton