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v7.1-rc7
26407 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Linus Torvalds
|
4a694a77c3 |
13 hotfixes. All are for MM. 10 are cc:stable and the remaining 3
address post-7.1 issues or aren't considered suitable for backporting. There's a 3 patch series "userfaultfd: verify VMA state across UFFDIO_COPY retry" from Mike Rapoport which fixes a few uffd things. The rest are singletons - please see the individual changelogs for details. -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCah5U6wAKCRDdBJ7gKXxA jmzcAP9N+WQo4qNZYYjSURqJof48Q4nght5C0ZHtsVk5itNJEQEAiecouCreqDSE VUY9mQHyEawIfORkPTUijnkjV8b+lwc= =m8J3 -----END PGP SIGNATURE----- Merge tag 'mm-hotfixes-stable-2026-06-01-20-58' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM fixes from Andrew Morton: "13 hotfixes. All are for MM. 10 are cc:stable and the remaining 3 address post-7.1 issues or aren't considered suitable for backporting. There's a three-patch series "userfaultfd: verify VMA state across UFFDIO_COPY retry" from Mike Rapoport which fixes a few uffd things. The rest are singletons - please see the individual changelogs for details" * tag 'mm-hotfixes-stable-2026-06-01-20-58' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: userfaultfd: remove redundant check in vm_uffd_ops() userfaultfd: refuse to __mfill_atomic_pte() for unsupported VMAs userfaultfd: verify VMA state across UFFDIO_COPY retry mm/huge_memory: update file PMD counter before folio_put() mm/huge_memory: update file PUD counter before folio_put() mm/hugetlb_vmemmap: fix incorrect vmemmap restore in rollback mm/damon/ops-common: call folio_test_lru() after folio_get() mm/cma: fix reserved page leak on activation failure mm/memory-failure: fix hugetlb_lock AA deadlock in get_huge_page_for_hwpoison mm/hugetlb: restore reservation on error in hugetlb folio copy paths mm/cma_debug: fix invalid accesses for inactive CMA areas memcg: use round-robin victim selection in refill_stock mm/hugetlb: avoid false positive lockdep assertion |
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|
Mike Rapoport (Microsoft)
|
9d7bea186b |
userfaultfd: remove redundant check in vm_uffd_ops()
Lorenzo says:
static const struct vm_uffd_ops *vma_uffd_ops(struct vm_area_struct *vma)
{
if (vma_is_anonymous(vma))
return &anon_uffd_ops;
return vma->vm_ops ? vma->vm_ops->uffd_ops : NULL;
}
This is doing a redundant check _and_ making life confusing, as if
!vma->vm_ops is a condition that can be reached there, it can't, as
vma_is_anonymous() is literally a !vma->vm_ops check :)
Remove the redundant check.
Link: https://lore.kernel.org/20260527184751.4147364-4-rppt@kernel.org
Fixes:
|
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|
Mike Rapoport (Microsoft)
|
df3ee3b3bb |
userfaultfd: refuse to __mfill_atomic_pte() for unsupported VMAs
__mfill_atomic_pte() unconditionally dereferences ops because there is an
assumption that VMAs that can undergo mfill_* operations are vetted on
registration and must have valid vm_uffd_ops.
Add a guard against potential bugs and make sure __mfill_atomic_pte()
bails out if ops is NULL.
Link: https://lore.kernel.org/20260527184751.4147364-3-rppt@kernel.org
Fixes:
|
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|
Mike Rapoport (Microsoft)
|
85668fda93 |
userfaultfd: verify VMA state across UFFDIO_COPY retry
Patch series "userfaultfd: verify VMA state across UFFDIO_COPY retry", v2. ... and two more small fixes. This patch (of 3): mfill_copy_folio_retry() drops the VMA lock for copy_from_user() and reacquires it afterwards. The destination VMA can be replaced during that window. The existing check compares vma_uffd_ops() before and after the retry, but if a shmem VMA with MAP_SHARED is replaced with a shmem VMA with MAP_PRIVATE (or vice versa) the replacement goes undetected. The change from MAP_PRIVATE to MAP_SHARED will treat the folio allocated with shmem_alloc_folio() as anonymous and this will cause BUG() when mfill_atomic_install_pte() will try to folio_add_new_anon_rmap(). The change from MAP_SHARED to MAP_PRIVATE allows injection of folios into the page cache of the original VMA. There is no need to change for hugetlb because it never uses mfill_copy_folio_retry(). Introduce helpers for more comprehensive comparison of VMA state: - mfill_retry_state_save() to save the relevant VMA state into a struct mfill_retry_state (original uffd_ops, relevant VMA flags, vm_file and pgoff) before dropping the lock - mfill_retry_state_changed() to compare the saved state with the state of the VMA acquired after retaking the locks - mfill_retry_state_put() to release vm_file pinning. Use DEFINE_FREE() cleanup to wrap mfill_retry_state_put() to avoid complicating error handling paths in mfill_copy_folio_retry(). Link: https://lore.kernel.org/20260527184751.4147364-1-rppt@kernel.org Link: https://lore.kernel.org/20260527184751.4147364-2-rppt@kernel.org Fixes: |
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|
Yin Tirui
|
8d87805992 |
mm/huge_memory: update file PMD counter before folio_put()
__split_huge_pmd_locked() updates the file/shmem RSS counter after
dropping the PMD mapping's folio reference. If folio_put() drops the last
reference, mm_counter_file() can later read freed folio state via
folio_test_swapbacked().
Move the counter update before folio_put().
Link: https://lore.kernel.org/20260526101337.1984081-1-yintirui@huawei.com
Fixes:
|
||
|
Yin Tirui
|
40990c87a2 |
mm/huge_memory: update file PUD counter before folio_put()
__split_huge_pud_locked() updates the file/shmem RSS counter after
dropping the PUD mapping's folio reference. If folio_put() drops the last
reference, mm_counter_file() can later read freed folio state via
folio_test_swapbacked().
Move the counter update before folio_put().
Link: https://lore.kernel.org/20260526101355.1984244-1-yintirui@huawei.com
Fixes:
|
||
|
Muchun Song
|
c7bde43f6d |
mm/hugetlb_vmemmap: fix incorrect vmemmap restore in rollback
vmemmap_restore_pte() rebuilds restored vmemmap pages from a tail-page
template derived from compound_head(). This is wrong when the current PTE
already maps a page whose contents are not tail-page metadata.
In the rollback path of vmemmap_remap_free(), the first restored PTE is
backed by vmemmap_head and contains head-page metadata. Reconstructing
that page from a tail-page template overwrites the head-page state and
corrupts the restored vmemmap page.
Fix this by copying the full page from the page currently mapped by the
PTE. Also pass vmemmap_tail to the rollback walk so only PTEs backed by
the shared tail page are restored, while the head PTE remains mapped to
vmemmap_head. Add VM_WARN_ON_ONCE() checks for unexpected cases.
Link: https://lore.kernel.org/20260525025213.2229628-1-songmuchun@bytedance.com
Fixes:
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|
SeongJae Park
|
d6b8b02a27 |
mm/damon/ops-common: call folio_test_lru() after folio_get()
damon_get_folio() speculatively calls folio_test_lru() before folio_try_get(). The folio can get freed and reallocated to a tail page. In the case, VM_BUG_ON_PGFLAGS() in const_folio_flags() can be triggered. Remove the speculative call. Also mark folio_test_lru() check right after folio_try_get() success as no more unlikely. The race should be rare. Also the problem can happen only if the kernel has enabled CONFIG_DEBUG_VM_PGFLAGS. No real world report of this issue has been made so far. This fix is based on only theoretical analysis. That said, a bug is a bug. A similar issue was also fixed via commit |
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Linus Torvalds
|
a29c0b0caf |
memblock: fix regression from memblock_free_late() refactoring
After refactoring of memblock_free_late() and free_init_pages() it became possible to call memblock_free() after memblock init data was discarded. Make sure memblock_free() does not touch memblock.reserved unless it is called early enough or when ARCH_KEEP_MEMBLOCK is enabled. -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEeOVYVaWZL5900a/pOQOGJssO/ZEFAmobERsACgkQOQOGJssO /ZGiqQgArOfAxLDWWinyherNcejWY+GKsNdWNYoGOv8UEw2oTTBmjyrOqHrGcevQ YlLjBxc2v9LzW9wCRnW0ngoq6/28ABLwyLpB+sMyHU8KaJDyYnAhfe7xt59aqE2N JuQaSRY8irZG8g2Yks2ZWIPbDoIXJVvGI342L96OYLO63eehV9u5e7kbBebOZpH1 JlnbsaMGjhh2RgLrWWEy4EW1NZ5bYHer6fmCVIlUWtz9X67OjKD5na8bdi9ADEay Wu2CjYwZFdScM4FQ8r2l9UHxjnU8EQKRxVOm2+hO8wRiE3efzezDCp5Laacvf9o6 KLrkVONfYUpScis3qLpNZly3IjAeVw== =H1VN -----END PGP SIGNATURE----- Merge tag 'fixes-2026-05-30' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock Pull memblock fix from Mike Rapoport: "Fix regression from memblock_free_late() refactoring After refactoring of memblock_free_late() and free_init_pages() it became possible to call memblock_free() after memblock init data was discarded. Make sure memblock_free() does not touch memblock.reserved unless it is called early enough or when ARCH_KEEP_MEMBLOCK is enabled" * tag 'fixes-2026-05-30' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock: memblock: don't touch memblock arrays when memblock_free() is called late |
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|
Muchun Song
|
00739e4dd4 |
mm/cma: fix reserved page leak on activation failure
If cma_activate_area() fails after allocating only part of the range
bitmaps, the cleanup path still has to release the reserved pages when
CMA_RESERVE_PAGES_ON_ERROR is clear.
That is still worth doing even in this __init path. A bitmap_zalloc()
failure does not necessarily mean the system cannot make further progress:
freeing the reserved CMA pages can return a substantial amount of memory
to the buddy allocator and may relieve the temporary memory shortage that
caused the allocation failure in the first place.
However, the cleanup path currently uses the bitmap-freeing bound for page
release as well. That is only correct for ranges whose bitmap allocation
already succeeded. The failed range and all later ranges still keep their
reserved pages, so a partial bitmap allocation failure can permanently
leak them.
Fix this by releasing reserved pages for all ranges. Use the saved
early_pfn[] value for ranges whose bitmap allocation already succeeded and
for the failed range, and use cmr->early_pfn for later ranges whose bitmap
allocation was never attempted.
Link: https://lore.kernel.org/20260523060123.2207992-1-songmuchun@bytedance.com
Fixes:
|
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|
Wupeng Ma
|
3c2d42b8ee |
mm/memory-failure: fix hugetlb_lock AA deadlock in get_huge_page_for_hwpoison
Two concurrent madvise(MADV_HWPOISON) calls on the same hugetlb page can
trigger a recursive spinlock self-deadlock (AA deadlock) on hugetlb_lock
when racing with a concurrent unmap:
thread#0 thread#1
-------- --------
madvise(folio, MADV_HWPOISON)
-> poisons the folio successfully
madvise(folio, MADV_HWPOISON) unmap(folio)
try_memory_failure_hugetlb
get_huge_page_for_hwpoison
spin_lock_irq(&hugetlb_lock) <- held
__get_huge_page_for_hwpoison
hugetlb_update_hwpoison()
-> MF_HUGETLB_FOLIO_PRE_POISONED
goto out:
folio_put()
refcount: 1 -> 0
free_huge_folio()
spin_lock_irqsave(&hugetlb_lock)
-> AA DEADLOCK!
The out: path in __get_huge_page_for_hwpoison() calls folio_put() to drop
the GUP reference while the hugetlb_lock is still held by the hugetlb.c
wrapper get_huge_page_for_hwpoison(). If concurrent unmap has released
the page table mapping reference, folio_put() drops the folio refcount to
zero, triggering free_huge_folio() which attempts to re-acquire the
non-recursive hugetlb_lock.
Fix this by moving hugetlb_lock acquisition from the hugetlb.c wrapper
into get_huge_page_for_hwpoison(). Place spin_unlock_irq() before the
folio_put() at the out: label so the folio is always released outside the
lock.
[akpm@linux-foundation.org: fix race, rename label per Miaohe]
Link: https://sashiko.dev/#/patchset/20260522010305.4099834-1-mawupeng1@huawei.com
Link: https://lore.kernel.org/f39f405e-4b4b-8f79-70fe-a2b5b62114eb@huawei.com
Link: https://lore.kernel.org/20260522010305.4099834-1-mawupeng1@huawei.com
Fixes:
|
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|
David Carlier
|
40c81856e6 |
mm/hugetlb: restore reservation on error in hugetlb folio copy paths
Two sites in mm/hugetlb.c allocate a hugetlb folio via alloc_hugetlb_folio() (consuming a VMA reservation) and then call copy_user_large_folio(), which became int-returning in commit |
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Muchun Song
|
c0ca59beb5 |
mm/cma_debug: fix invalid accesses for inactive CMA areas
cma_activate_area() can fail after allocating range bitmaps. Its cleanup path frees those bitmaps, but only clears cma->count and cma->available_count. It leaves cma->nranges and each range's count in place, so cma_debugfs_init() can still register debugfs files for an area that never activated successfully. That exposes two problems. Reading the bitmap file can make debugfs walk a freed range bitmap and trigger an invalid memory access. Reading maxchunk can also take cma->lock even though that lock is initialized only on the successful activation path. Fix this by creating debugfs entries only for CMA areas that reached CMA_ACTIVATED. |
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Shakeel Butt
|
c0cafe24d3 |
memcg: use round-robin victim selection in refill_stock
Harry Yoo reported that get_random_u32_below() is not safe to call in the
nmi context and memcg charge draining can happen in nmi context.
More specifically get_random_u32_below() is neither reentrant- nor
NMI-safe: it acquires a per-cpu local_lock via local_lock_irqsave() on the
batched_entropy_u32 state. An NMI that lands on a CPU mid-update of the
ChaCha batch state and recurses into the random subsystem would corrupt
that state. The memcg_stock local_trylock prevents re-entry on the percpu
stock itself, but cannot protect an unrelated subsystem's per-cpu lock.
Replace the random pick with a per-cpu round-robin counter stored in
memcg_stock_pcp and serialized by the same local_trylock that already
guards cached[] and nr_pages[]. No atomics, no random calls, no extra
locks needed.
Link: https://lore.kernel.org/20260521223751.3794625-1-shakeel.butt@linux.dev
Fixes:
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Lorenzo Stoakes
|
b4aea43cd3 |
mm/hugetlb: avoid false positive lockdep assertion
Commit |
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Linus Torvalds
|
d60ec36cab |
13 hotfixes. 9 are for MM. 9 are cc:stable and the remaining 4 address
post-7.1 issues or aren't considered suitable for backporting. All patches are singletons - please see the individual changelogs for details. -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCahTZ2QAKCRDdBJ7gKXxA ju+UAQDUga+l95O1iOnrraKFWvT1ghQKTgbNxGMwefHjVLLFBQD+Ln2wPfz73Ks7 H8WK0k5D0g+6lKs6tFGAALdQnTU0BAU= =MYsv -----END PGP SIGNATURE----- Merge tag 'mm-hotfixes-stable-2026-05-25-16-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull misc fixes from Andrew Morton: "13 hotfixes. 9 are for MM. 9 are cc:stable and the remaining 4 address post-7.1 issues or aren't considered suitable for backporting. All patches are singletons - please see the individual changelogs for details" * tag 'mm-hotfixes-stable-2026-05-25-16-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: Revert "mm: introduce a new page type for page pool in page type" mm/vmalloc: do not trigger BUG() on BH disabled context MAINTAINERS, mailmap: change email for Eugen Hristev mm/migrate_device: fix pgtable leak in migrate_vma_insert_huge_pmd_page kernel/fork: validate exit_signal in kernel_clone() mm: memcontrol: propagate NMI slab stats to memcg vmstats mm/damon/sysfs-schemes: delete tried region in regions_rmdirs() mm/rmap: initialize nr_pages to 1 at loop start in try_to_unmap_one zram: fix use-after-free in zram_writeback_endio memfd: deny writeable mappings when implying SEAL_WRITE ipc: limit next_id allocation to the valid ID range Revert "mm/hugetlbfs: update hugetlbfs to use mmap_prepare" MAINTAINERS: .mailmap: update after GEHC spin-off |
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Mike Rapoport (Microsoft)
|
7c2eee9c13 |
memblock: don't touch memblock arrays when memblock_free() is called late
When memblock_free() is called after memblock_discard() on architectures
that don't select ARCH_KEEP_MEMBLOCK, it tries to update memblock.reserved
that was already discarded and it causes use-after-free, for example
[ 8.514775] BUG: KASAN: use-after-free in memblock_isolate_range+0x4ac/0x650
[ 8.514775] Read of size 8 at addr ffff88a07fe6a000 by task swapper/0/1
[ 8.514775] Call Trace:
[ 8.514775] <TASK>
[ 8.514775] kasan_report+0xb2/0x1b0
[ 8.514775] memblock_isolate_range+0x4ac/0x650
[ 8.514775] memblock_phys_free+0xc4/0x190
[ 8.514775] housekeeping_late_init+0x257/0x280
[ 8.514775] do_one_initcall+0xaa/0x470
[ 8.514775] do_initcalls+0x1b4/0x1f0
[ 8.514775] kernel_init_freeable+0x4b5/0x550
[ 8.514775] kernel_init+0x1c/0x150
[ 8.514775] ret_from_fork+0x5dc/0x8e0
[ 8.514775] ret_from_fork_asm+0x1a/0x30
[ 8.514775] </TASK>
Make sure memblock_free() updates memblock.reserved only when called early
enough or when ARCH_KEEP_MEMBLOCK is enabled.
Reported-by: Waiman Long <longman@redhat.com>
Reported-by: Breno Leitao <leitao@debian.org>
Closes: https://lore.kernel.org/all/20260505051821.1107133-1-longman@redhat.com
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Breno Leitao <leitao@debian.org>
Fixes:
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Linus Torvalds
|
de37e502a3 |
cgroup: Fixes for v7.1-rc4
Two rstat fixes:
- Out-of-bounds access in the css_rstat_updated() BPF kfunc when called
with an unchecked user-supplied cpu.
- Over-strict NMI guard after the recent switch to try_cmpxchg left
sparc and ppc64 unable to queue rstat updates from NMI.
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Merge tag 'cgroup-for-7.1-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
"Two rstat fixes:
- Out-of-bounds access in the css_rstat_updated() BPF kfunc when
called with an unchecked user-supplied cpu
- Over-strict NMI guard after the recent switch to try_cmpxchg left
sparc and ppc64 unable to queue rstat updates from NMI"
* tag 'cgroup-for-7.1-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: rstat: relax NMI guard after switch to try_cmpxchg
cgroup/rstat: validate cpu before css_rstat_cpu() access
|
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Linus Torvalds
|
46de4087d3 |
slab fixes for 7.1-rc4
-----BEGIN PGP SIGNATURE----- iQFPBAABCAA5FiEEe7vIQRWZI0iWSE3xu+CwddJFiJoFAmoQJvUbFIAAAAAABAAO bWFudTIsMi41KzEuMTIsMiwyAAoJELvgsHXSRYiavTcH/iKK1G+ygWOCqKrlZxir /Ga7vPPQSXgiZEtEQ9ZIC/1UQeBp/eQc4uCzgy/aAMqksFjdwsFF/qs6mUr1ffHB ne9RBk40zoP6KQfKkP8GW22ERmDOLnJ1t+QiCibrre8roM7vguDx0Sr5VXGoDmU5 p9mtomLzxJkuDV1gY7LGsT26Es+3PIpma8DTJwlhsUw2igAsp9XnfXJEjBu4eEXP vfGkxK+go5+u4iH5/qKKw6MpfmV7z+O5WJsHaGaKyp8chc6lMSkqtFe1g15h6j6D bL4D6jvmUuwTGsDVaufUnnKdM64+BtcCYJAkgzfKHhge8KG3eBlmsiLkK4uvNRo4 8NI= =E0Wr -----END PGP SIGNATURE----- Merge tag 'slab-for-7.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab Pull slab fix from Vlastimil Babka: - Stable fix for a missing cpus_read_lock in one of the cpu sheaves flushing paths (Qing Wang) * tag 'slab-for-7.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: mm/slub: hold cpus_read_lock around flush_rcu_sheaves_on_cache() |
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Byungchul Park
|
54cf41c969 |
Revert "mm: introduce a new page type for page pool in page type"
This reverts commit |
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Uladzislau Rezki (Sony)
|
04aa71da5f |
mm/vmalloc: do not trigger BUG() on BH disabled context
__get_vm_area_node() currently triggers a BUG() if in_interrupt() returns
true. However, in_interrupt() also reports true when BH are disabled.
The bridge code can call rhashtable_lookup_insert_fast() with bottom
halves disabled:
__vlan_add()
-> br_fdb_add_local()
spin_lock_bh(&br->hash_lock); <-- Disable BH
-> fdb_add_local()
-> fdb_create()
-> rhashtable_lookup_insert_fast()
-> kvmalloc()
-> vmalloc()
-> __get_vm_area_node()
-> BUG_ON(in_interrupt())
spin_unlock_bh(&br->hash_lock)
this triggers the BUG() despite the caller not being in NMI or
hard IRQ context.
Replace the in_interrupt() check with in_nmi() || in_hardirq().
Link: https://lore.kernel.org/20260515153009.2296191-1-urezki@gmail.com
Fixes:
|
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Sunny Patel
|
2c6f81d587 |
mm/migrate_device: fix pgtable leak in migrate_vma_insert_huge_pmd_page
When migrate_vma_insert_huge_pmd_page() jumps to unlock_abort due
to a PMD check failure, the pgtable allocated earlier via
pte_alloc_one() is never freed, causing a memory leak.
Added free_abort label to release the pgtable in error path.
Link: https://lore.kernel.org/20260501115122.23288-1-nueralspacetech@gmail.com
Fixes:
|
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|
Alexandre Ghiti
|
e16f17a9c5 |
mm: memcontrol: propagate NMI slab stats to memcg vmstats
flush_nmi_stats() drains per-node NMI slab atomics into the per-node
lruvec_stats, but does not propagate them to the memcg-level vmstats.
For non NMI case, account_slab_nmi_safe() calls mod_memcg_lruvec_state()
which updates both per-node lruvec_stats and memcg-level vmstats, so
flush_nmi_stats() needs to flush to per-node lruvec_stats as well as
memcg-level vmstats.
So fix this by flushing to the memcg-level vmstats for NMI too.
Link: https://lore.kernel.org/20260518082830.599102-1-alex@ghiti.fr
Fixes:
|
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|
SeongJae Park
|
441f92f7d3 |
mm/damon/sysfs-schemes: delete tried region in regions_rmdirs()
DAMON sysfs maintains the DAMOS tried region directory objects via a
linked list. When the user requests refresh of the directories, DAMON
sysfs removes all the region directories first, and then generate updated
regions directory on the empty space. The removal function
(damon_sysfs_scheme_regions_rm_dirs()) only puts the kobj objects.
Deletion of the container region object from the linked list is done
inside the kobj release callback function.
If somehow the callback invocation is delayed, the list will contain
regions list that gonna be freed. If the updated region directories
creation is started in this situation, the list can be corrupted and
use-after-free can happen.
Because the kobj objects are managed by only DAMON sysfs, the issue cannot
happen in normal situation. But, such delays can be made on kernels that
built with CONFIG_DEBUG_KOBJECT_RELEASE. On the kernel, the issue can
indeed be reproduced like below.
# damo start --damos_action stat
# cd /sys/kernel/mm/damon/admin/kdamonds/0/
# for i in {1..10}; do echo update_schemes_tried_regions > state; done
# dmesg | grep underflow
[ 89.296152] refcount_t: underflow; use-after-free.
Fix the issue by removing the region object from the list when
decrementing the reference count.
Also update damos_sysfs_populate_region_dir() to add the region object to
the list only after the kobject_init_and_add() is success, so that fail of
kobject_init_and_add() is not leaving the deallocated object on the list.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260518152559.93038-1-sj@kernel.org
Link: https://lore.kernel.org/20260513011920.119183-1-sj@kernel.org [1]
Fixes:
|
||
|
Dev Jain
|
3f8968e9cb |
mm/rmap: initialize nr_pages to 1 at loop start in try_to_unmap_one
Initialize nr_pages to 1 at the start of each loop iteration, like
folio_referenced_one() does.
Without this, nr_pages computed by a previous folio_unmap_pte_batch() call
can be reused on a later iteration that does not run
folio_unmap_pte_batch() again.
mmap a 64K large folio with MAP_ANONYMOUS | MAP_DROPPABLE, then call
madvise(MADV_FREE), then make the last page device-exclusive via
HMM_DMIRROR_EXCLUSIVE.
Trigger node reclaim through sysfs. Now, in try_to_unmap_one(), we will
first clear the first 15 out of 16 entries mapping the lazyfree folio.
This will set nr_pages to 15. In the next pvmw walk, this nr_pages gets
reused on a device-exclusive pte, thus potentially corrupting folio
refcount/mapcount.
At the moment, I have a userspace program which can make the kernel spit
out a trace, but the blow up is in folio_referenced_one(), because there
are existing bugs in the interaction between device-private and rmap
(which too I am investigating). I did a one liner kernel change to avoid
going into folio_referenced_one(), and the kernel blows up at
folio_remove_rmap_ptes in try_to_unmap_one which is what I wanted.
Note that the bug is there not since file folio batching but lazyfree
folio batching, since device-exclusive only works for anonymous folios.
Userspace visible effect is simply kernel crashing somewhere due to
refcount/mapcount corruption.
Link: https://lore.kernel.org/20260518063656.3721056-1-dev.jain@arm.com
Fixes:
|
||
|
Pratyush Yadav (Google)
|
3b041514cb |
memfd: deny writeable mappings when implying SEAL_WRITE
When SEAL_EXEC is added, SEAL_WRITE is implied to make W^X. But the
implied seal is set after the check that makes sure the memfd can not have
any writable mappings. This means one can use SEAL_EXEC to apply
SEAL_WRITE while having writeable mappings.
This breaks the contract that SEAL_WRITE provides and can be used by an
attacker to pass a memfd that appears to be write sealed but can still be
modified arbitrarily.
Fix this by adding the implied seals before the call for
mapping_deny_writable() is done.
Link: https://lore.kernel.org/20260505133922.797635-1-pratyush@kernel.org
Fixes:
|
||
|
Lorenzo Stoakes
|
83f9efcce9 |
Revert "mm/hugetlbfs: update hugetlbfs to use mmap_prepare"
This reverts commit |
||
|
Linus Torvalds
|
c6e99c10fd |
14 hotfixes. 9 are for MM. 10 are cc:stable and the remainder are for
post-7.1 issues or aren't deemed suitable for backporting. There's a 2 patch MAINTAINERS series from Mike Rapoport which updates us for the new KEXEC/KDUMP/crash/LUO/etc arrangements. And a 2 patch series from Muchun Song to fix a couple of memory-hotplug issues. Otherwise singletons, please see the changelogs for details. -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCagviKQAKCRDdBJ7gKXxA jlbsAP9SEShHxXEYcRMVQtXb+8/iJDe7J3KwVDP4e0VOlQKTPAD/c+C2bx4nllOG 77wl9Qkr++KqTSmoPbzA7Q02gJC2ngQ= =2qN3 -----END PGP SIGNATURE----- Merge tag 'mm-hotfixes-stable-2026-05-18-21-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull misc fixes from Andrew Morton: "14 hotfixes. 9 are for MM. 10 are cc:stable and the remainder are for post-7.1 issues or aren't deemed suitable for backporting. There's a two-patch MAINTAINERS series from Mike Rapoport which updates us for the new KEXEC/KDUMP/crash/LUO/etc arrangements. And another two-patch series from Muchun Song to fix a couple of memory-hotplug issues. Otherwise singletons, please see the changelogs for details" * tag 'mm-hotfixes-stable-2026-05-18-21-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mm/memory: fix spurious warning when unmapping device-private/exclusive pages mm: fix __vm_normal_page() to handle missing support for pmd_special()/pud_special() drivers/base/memory: fix memory block reference leak in poison accounting mm/memory_hotplug: fix memory block reference leak on remove lib: kunit_iov_iter: fix test fail on powerpc mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free MAINTAINERS: add kexec@ list to LIVE UPDATE ENTRY MAINTAINERS: add tree for KDUMP and KEXEC selftests/mm: run_vmtests.sh: fix destructive tests invocation scripts/gdb: slab: update field names of struct kmem_cache scripts/gdb: mm: cast untyped symbols in x86_page_ops mm/damon: fix damos_stat tracepoint format for sz_applied mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break() mm/migrate_device: fix spinlock leak in migrate_vma_insert_huge_pmd_page |
||
|
Qing Ming
|
8817005efb |
cgroup/rstat: validate cpu before css_rstat_cpu() access
css_rstat_updated() is exposed as a BPF kfunc and accepts a
caller-provided cpu argument. The function uses cpu for per-cpu rstat
lookups without checking whether it refers to a valid possible CPU.
A BPF iter/cgroup program with CAP_BPF and CAP_PERFMON can pass an
invalid cpu value. On an unfixed UBSCAN_BOUNDS test kernel, cpu ==
0x7fffffff triggers:
UBSAN: array-index-out-of-bounds in kernel/cgroup/rstat.c:31:9
index 2147483647 is out of range for type 'long unsigned int [64]'
Call Trace:
css_rstat_updated
bpf_iter_run_prog
cgroup_iter_seq_show
bpf_seq_read
Add cpu validation to the BPF-facing css_rstat_updated() kfunc and
move the common implementation to __css_rstat_updated() for in-kernel
callers.
Fixes:
|
||
|
Linus Torvalds
|
fd6b566156 |
This push contains the following changes:
- Fix potential dead-lock in rhashtable when used by xattr. - Avoid calling kvfree on atomic path in rhashtable. -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEn51F/lCuNhUwmDeSxycdCkmxi6cFAmoG6NgACgkQxycdCkmx i6dpPA/9FUJGxLosr5LKlo71af5RpHuOAAVq9/3tjev9FLVR0IgqUuMpPqcKqaBC w4HL2drDcXUm3tlFLAgRgnCcIbz1lIVrZMTSHg1ivx9ZGNWm75o7n2gnYp4NnFzD 5A8AKHGUfnLf0y/nnrehvgGpnuyEGuMVL2+lTnkfJi1gYGQfJszC2pvC8a7gK2m1 ZXPdTEuMe58nfqHK0Jkhfwwjh8glpopvwfrEp5mByRqr3EELKznNGnTlPNpyjkPd vV0W8CM5qPJCn5Ts7OTKnZFktelSfgjKeHhxK3QFfUPV/fFQtwn2dNp099w00xMY GC3okWgDMGoXqnQ6nzNt9IGPXIvh1KgH76qY35R4gAjZ5JX8YF7ObJGylAthRYKz +AGx9Pl9u2GIE0EzkHDG5kxel2tCajWOgbdm78xYUtEn9ii3j8LInX63lB1bLLaq KIxMG/IuxP6mMaSiOs79/B9qmT/gYEfJvf4x8EXV1HXvzQh7SD5Zcep+krhVj49+ rsP5SBcTZfiZapU+AlicquLO/1kCYucUHz15KoKkeXiwj5ruWuUNx/wNblzft94d 9H4zfqL5hE41wiSOPdOT5fbGOI/a1PlMj4js3w+CGNh4BBOjAU6fZj86tO9gwI27 aRyR62ziteLck474PsYQbKx7J2qk2EARxO8QL9vHZhAsq3MBOck= =dSj/ -----END PGP SIGNATURE----- Merge tag 'v7.1-p4' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto fixes from Herbert Xu: - Fix potential dead-lock in rhashtable when used by xattr - Avoid calling kvfree on atomic path in rhashtable * tag 'v7.1-p4' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: rhashtable: Add bucket_table_free_atomic() helper mm/slab: Add kvfree_atomic() helper rhashtable: drop ht->mutex in rhashtable_free_and_destroy() |
||
|
Qing Wang
|
67ea9d353d |
mm/slub: hold cpus_read_lock around flush_rcu_sheaves_on_cache()
flush_rcu_sheaves_on_cache() calls queue_work_on() in a
for_each_online_cpu() loop, which requires the cpu to stay online.
But cpus_read_lock() is not held in kvfree_rcu_barrier_on_cache() and the
set of "online cpus" is subject to change.
There are two paths that call flush_rcu_sheaves_on_cache():
// has cpus_read_lock()
flush_all_rcu_sheaves()
-> flush_rcu_sheaves_on_cache()
// no cpus_read_lock()
kvfree_rcu_barrier_on_cache()
-> flush_rcu_sheaves_on_cache()
Fix this by holding cpus_read_lock() in kvfree_rcu_barrier_on_cache().
Why not move cpus_read_lock() from flush_all_rcu_sheaves() into
flush_rcu_sheaves_on_cache()? The reason is it would introduce a new lock
order (slab_mutex -> cpu_hotplug_lock). The reverse order
(cpu_hotplug_lock -> slab_mutex) is established by
- cpuhp_setup_state_nocalls(..., slub_cpu_setup, ...)
- kmem_cache_destroy()
The two orders together would form an AB-BA deadlock.
Finally, add lockdep_assert_cpus_held() in flush_rcu_sheaves_on_cache()
to catch the same problem in the future.
Fixes:
|
||
|
Alistair Popple
|
be3f38d05c |
mm/memory: fix spurious warning when unmapping device-private/exclusive pages
Device private and exclusive entries are only supported for anonymous
folios. This condition is tested in __migrate_device_pages() and
make_device_exclusive() using folio_test_anon(). However the unmap path
tests this assumption using vma_is_anonymous().
This is wrong because whilst anonymous VMAs can only contain folios where
folio_test_anon() is true the opposite relation does not hold. A folio
for which folio_test_anon() is true does not imply vma_is_anonymous() is
true. Such a condition can occur if for example a folio is part of a
private filebacked mapping.
In this case vma_is_anonymous() is false as the mapping is filebacked, but
folio_test_anon() may be true, thus permitting devices to migrate the
folio to device private memory. This can lead to the following spurious
warnings during process teardown:
[ 772.737706] ------------[ cut here ]------------
[ 772.739201] WARNING: mm/memory.c:1754 at unmap_page_range.cold+0x26/0x18a, CPU#17: hmm-tests/2041
[ 772.742050] Modules linked in: test_hmm nvidia_uvm(O) nvidia(O)
[ 772.743959] CPU: 17 UID: 0 PID: 2041 Comm: hmm-tests Tainted: G W O 7.0.0+ #387 PREEMPT(full)
[ 772.747104] Tainted: [W]=WARN, [O]=OOT_MODULE
[ 772.748509] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
[ 772.752117] RIP: 0010:unmap_page_range.cold+0x26/0x18a
[ 772.753780] Code: 7e fe ff ff 48 89 4c 24 78 4c 89 44 24 38 e8 f2 ff b1 00 48 8b 4c 24 78 4c 8b 44 24 38 48 8b 44 24 18 48 83 78 48 00 74 04 90 <0f> 0b 90 48 89 ca b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a 80 3c 02
[ 772.759602] RSP: 0018:ffff888112607550 EFLAGS: 00010286
[ 772.761310] RAX: ffff88811bbf4dc0 RBX: dffffc0000000000 RCX: ffffea03e9bfffd8
[ 772.763583] RDX: 1ffff1102377e9c1 RSI: 0000000000000008 RDI: ffff88811bbf4e08
[ 772.765914] RBP: 0000000000000006 R08: ffff8881059f7448 R09: ffffed10224c0e68
[ 772.768184] R10: ffff888112607347 R11: 0000000000000001 R12: 0000000000000001
[ 772.770461] R13: ffffea03e9bfffc0 R14: ffff888112607908 R15: ffffea03e9bfffc0
[ 772.772782] FS: 00007f327caa2780(0000) GS:ffff888427b7d000(0000) knlGS:0000000000000000
[ 772.775328] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 772.777187] CR2: 00007f327ca89000 CR3: 00000001994d5000 CR4: 00000000000006f0
[ 772.779135] Call Trace:
[ 772.779792] <TASK>
[ 772.780317] ? dmirror_interval_invalidate+0x1a3/0x290 [test_hmm]
[ 772.781873] ? vm_normal_page_pud+0x2b0/0x2b0
[ 772.782992] ? __rwlock_init+0x150/0x150
[ 772.784006] ? lock_release+0x216/0x2b0
[ 772.785008] ? __mmu_notifier_invalidate_range_start+0x505/0x6e0
[ 772.786522] ? lock_release+0x216/0x2b0
[ 772.787498] ? unmap_single_vma+0xb6/0x210
[ 772.788573] unmap_vmas+0x27d/0x520
[ 772.789506] ? unmap_single_vma+0x210/0x210
[ 772.790607] ? mas_update_gap.part.0+0x620/0x620
[ 772.791834] unmap_region+0x19e/0x350
[ 772.792769] ? remove_vma+0x130/0x130
[ 772.793684] ? mas_alloc_nodes+0x1f2/0x300
[ 772.794730] vms_complete_munmap_vmas+0x8c1/0xe20
[ 772.795926] ? unmap_region+0x350/0x350
[ 772.796917] do_vmi_align_munmap+0x36a/0x4e0
[ 772.798018] ? lock_release+0x216/0x2b0
[ 772.799024] ? vma_shrink+0x620/0x620
[ 772.799983] do_vmi_munmap+0x150/0x2c0
[ 772.800939] __vm_munmap+0x161/0x2c0
[ 772.801872] ? expand_downwards+0xd60/0xd60
[ 772.802948] ? clockevents_program_event+0x1ef/0x540
[ 772.804217] ? lock_release+0x216/0x2b0
[ 772.805158] __x64_sys_munmap+0x59/0x80
[ 772.805776] do_syscall_64+0xfc/0x670
[ 772.806336] ? irqentry_exit+0xda/0x580
[ 772.806976] entry_SYSCALL_64_after_hwframe+0x4b/0x53
[ 772.807772] RIP: 0033:0x7f327cbb2717
[ 772.808323] Code: 73 01 c3 48 8b 0d f9 76 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c9 76 0d 00 f7 d8 64 89 01 48
[ 772.811337] RSP: 002b:00007ffde7f57d38 EFLAGS: 00000202 ORIG_RAX: 000000000000000b
[ 772.812564] RAX: ffffffffffffffda RBX: 00007f327cc9c000 RCX: 00007f327cbb2717
[ 772.813733] RDX: 0000000000000000 RSI: 0000000000400000 RDI: 00007f327c289000
[ 772.814867] RBP: 0000000000421360 R08: 000000000000001a R09: 0000000000000000
[ 772.815991] R10: 0000000000000003 R11: 0000000000000202 R12: 00007ffde7f57d74
[ 772.817121] R13: 00007f327c689010 R14: 0000000000100000 R15: 00007f327c289000
[ 772.818272] </TASK>
[ 772.818614] irq event stamp: 0
[ 772.819159] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[ 772.820174] hardirqs last disabled at (0): [<ffffffff82a57ab3>] copy_process+0x19f3/0x6440
[ 772.821511] softirqs last enabled at (0): [<ffffffff82a57b00>] copy_process+0x1a40/0x6440
[ 772.822869] softirqs last disabled at (0): [<0000000000000000>] 0x0
[ 772.823871] ---[ end trace 0000000000000000 ]---
Fix this by using the same check for folio_test_anon() in
zap_nonpresent_ptes(). Also add a hmm-test case for this.
Link: https://lore.kernel.org/20260501065116.2057242-1-apopple@nvidia.com
Fixes:
|
||
|
David Hildenbrand (Arm)
|
c0c6ccd982 |
mm: fix __vm_normal_page() to handle missing support for pmd_special()/pud_special()
On x86 32-bit with THP enabled, zap_huge_pmd() is seen to generate a "WARNING: mm/memory.c:735 at __vm_normal_page+0x6a/0x7d", from the VM_WARN_ON_ONCE(is_zero_pfn(pfn) || is_huge_zero_pfn(pfn)); followed by "BUG: Bad rss-counter state"s, then later "BUG: Bad page state"s when reclaim gets to call shrink_huge_zero_folio_scan(). It's as if the _PAGE_SPECIAL bit never got set in the huge_zero pmd: and indeed, whereas pte_special() and pte_mkspecial() are subject to a dedicated CONFIG_ARCH_HAS_PTE_SPECIAL, pmd_special() and pmd_mkspecial() are subject to CONFIG_ARCH_SUPPORTS_PMD_PFNMAP, which is never enabled on any 32-bit architecture. While the problem was exposed through commit |
||
|
Muchun Song
|
93866f55f7 |
mm/memory_hotplug: fix memory block reference leak on remove
Patch series "mm: Fix memory block leaks and locking", v2.
This series fixes two memory block device reference leaks and one locking
issue around the per-memory_block hwpoison counter.
This patch (of 2):
remove_memory_blocks_and_altmaps() looks up each memory block with
find_memory_block(), which acquires a reference to the memory block
device.
That reference is never dropped on this path, resulting in a leaked device
reference when removing memory blocks and their altmaps. Drop the
reference after retrieving mem->altmap and clearing mem->altmap, before
removing the memory block device.
Link: https://lore.kernel.org/20260428085219.1316047-1-songmuchun@bytedance.com
Link: https://lore.kernel.org/20260428085219.1316047-2-songmuchun@bytedance.com
Fixes:
|
||
|
David Hildenbrand (Arm)
|
6a288a4ddb |
mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free
__GFP_ZEROTAGS semantics are currently a bit weird, but effectively this
flag is only ever set alongside __GFP_ZERO and __GFP_SKIP_KASAN.
If we run with init_on_free, we will zero out pages during
__free_pages_prepare(), to skip zeroing on the allocation path.
However, when allocating with __GFP_ZEROTAG set, post_alloc_hook() will
consequently not only skip clearing page content, but also skip clearing
tag memory.
Not clearing tags through __GFP_ZEROTAGS is irrelevant for most pages that
will get mapped to user space through set_pte_at() later: set_pte_at() and
friends will detect that the tags have not been initialized yet
(PG_mte_tagged not set), and initialize them.
However, for the huge zero folio, which will be mapped through a PMD
marked as special, this initialization will not be performed, ending up
exposing whatever tags were still set for the pages.
The docs (Documentation/arch/arm64/memory-tagging-extension.rst) state
that allocation tags are set to 0 when a page is first mapped to user
space. That no longer holds with the huge zero folio when init_on_free is
enabled.
Fix it by decoupling __GFP_ZEROTAGS from __GFP_ZERO, passing to
tag_clear_highpages() whether we want to also clear page content.
Invert the meaning of the tag_clear_highpages() return value to have
clearer semantics.
Reproduced with the huge zero folio by modifying the check_buffer_fill
arm64/mte selftest to use a 2 MiB area, after making sure that pages have
a non-0 tag set when freeing (note that, during boot, we will not actually
initialize tags, but only set KASAN_TAG_KERNEL in the page flags).
$ ./check_buffer_fill
1..20
...
not ok 17 Check initial tags with private mapping, sync error mode and mmap memory
not ok 18 Check initial tags with private mapping, sync error mode and mmap/mprotect memory
...
This code needs more cleanups; we'll tackle that next, like
decoupling __GFP_ZEROTAGS from __GFP_SKIP_KASAN.
[akpm@linux-foundation.org: s/__GPF_ZERO/__GFP_ZERO/, per David]
Link: https://lore.kernel.org/20260421-zerotags-v2-1-05cb1035482e@kernel.org
Fixes:
|
||
|
SeongJae Park
|
d4e7b5c4cc |
mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break()
damon_sysfs_memcg_path_to_id() breaks mem_cgroup_iter() loop without
calling mem_cgroup_iter_break(). This leaks the cgroup reference. Fix
the issue by calling mem_cgroup_iter_break() before the break.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260426173625.86521-1-sj@kernel.org
Link: https://lore.kernel.org/20260423004148.74722-1-sj@kernel.org [1]
Fixes:
|
||
|
Sunny Patel
|
63451de16e |
mm/migrate_device: fix spinlock leak in migrate_vma_insert_huge_pmd_page
When check_stable_address_space() fails after the PMD spinlock has
been acquired via pmd_lock(), the code jumps directly to the abort
label, bypassing the spin_unlock() call in unlock_abort. This causes
the PMD spinlock to be permanently held, leading to a deadlock.
Change the goto target from abort to unlock_abort to ensure the
spinlock is always released on this error path.
Link: https://lore.kernel.org/20260425133537.17463-1-nueralspacetech@gmail.com
Fixes:
|
||
|
Linus Torvalds
|
1f63dd8ca0 |
liveupdate fixes for v7.1-rc4
A few fixes for kexec handover and liveupdate: * make sure KHO is skipped for crash kernel * fix error reporting in memfd preservation if it fails mid-loop * don't allow preserving memfds whose page count exceeds UINT_MAX * fix documentation of memfd seals preservation to match the code -----BEGIN PGP SIGNATURE----- iQFEBAABCgAuFiEEeOVYVaWZL5900a/pOQOGJssO/ZEFAmoET5gQHHJwcHRAa2Vy bmVsLm9yZwAKCRA5A4Ymyw79kVfdB/99gLJy40MO9ZCHSxRQD9TE7Fbuv71flVuD wmDz43UOyDIEp+qCB0VcNQPG3v+UINygUMGHkhOG4fgKLm0bEORXIJHNr8sTXYYk LuxN8g+Xv1P/qkucEIXy1oB38okg9cORhlfrCOiwpWBjNt5/AqZYKWttDshuZiIM kjIKEDtTZ/nDLXjkWAa4Qs4MtBjqTVCrG3glSNHT0yiFDEkAejXbr4RZ/Ght/9pz FwHzTfdIOnecvOCD2OHVQx9TJluaP57mlxTkOXJV6OApg0wiHjohl0Xcerh+JfB4 HAdF7xpr5Sk/BQVc3ygsDKwfTVfB/eYMfCoyUkXg9AVhcoBXmhD0 =luI7 -----END PGP SIGNATURE----- Merge tag 'fixes-2026-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux Pull liveupdate fixes from Mike Rapoport: "A few fixes for kexec handover and liveupdate: - make sure KHO is skipped for crash kernel - fix error reporting in memfd preservation if it fails mid-loop - don't allow preserving memfds whose page count exceeds UINT_MAX - fix documentation of memfd seals preservation to match the code" * tag 'fixes-2026-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux: mm/memfd_luo: document preservation of file seals mm/memfd_luo: reject memfds whose page count exceeds UINT_MAX mm/memfd_luo: report error when restoring a folio fails mid-loop kho: skip KHO for crash kernel |
||
|
Uladzislau Rezki (Sony)
|
dad0d91cc2 |
mm/slab: Add kvfree_atomic() helper
kvmalloc() now supports non-sleeping GFP flags, including the vmalloc fallback path. This means it may return vmalloc memory even for GFP_ATOMIC and GFP_NOWAIT allocations. Freeing such memory with kvfree() may then end up calling vfree(), which is not safe for non-sleeping contexts. Introduce kvfree_atomic() helper for such cases. It mirrors kvfree(), but uses vfree_atomic() for vmalloced memory. Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Acked-by: Harry Yoo (Oracle) <harry@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
||
|
David Carlier
|
7b0b68b2b9
|
mm/memfd_luo: document preservation of file seals
Commit |
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David Carlier
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d581fc99d3
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mm/memfd_luo: reject memfds whose page count exceeds UINT_MAX
memfd_luo_preserve_folios() declares max_folios as unsigned int and
computes it from the inode size, then passes it to memfd_pin_folios()
which itself caps max_folios at unsigned int. For files whose base-page
count exceeds UINT_MAX (larger than 16 TiB with 4 KiB pages), the
assignment truncates silently: only a prefix of the file gets pinned and
preserved, while memfd_luo_preserve() still records the full inode size
in ser->size. On retrieve the inode is restored to the full size but
only the preserved prefix repopulates the page cache, so the tail comes
back as holes and user data is silently lost across the live update.
Reject such files at preserve time with -EFBIG rather than chunk the
pin loop, which would also require enlarging the preserved folios array
well beyond what is practical.
Fixes:
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Linus Torvalds
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811129272d |
slab fixes for 7.1-rc1
-----BEGIN PGP SIGNATURE----- iQFPBAABCAA5FiEEe7vIQRWZI0iWSE3xu+CwddJFiJoFAmn3BZgbFIAAAAAABAAO bWFudTIsMi41KzEuMTIsMiwyAAoJELvgsHXSRYiabzcIAIDyPybWZ/bRup/KfWGE GknYLaUA3nw9ZpZQdQ0cJ+jGO6pfoUqacO0cZ/5ppdcXblKz22AFItUnpsd44M9H 92QjwNJoT6vjgzaSWCDE/6TeE0y27HjyhBlIYjs9mTRTb8sIH+mzfDS58FZponb/ RZMGmcJvS4La+VzaetAxzyx+cX7J9W/7zDfvz/qPMpm8tysGe4z8H7/54c5x/U+c NvuEXaxPaKEa62x5e+IFG6G67NszbJnfRrLGn/UMwp+SS5WUId6D9kmjtT70yJlg hbdU6zw6kI+DIPxRidnpI/iJqcA08r9UuC/TrZwcjaM6sythev5UvOxZXMRVp19w qXU= =yAe1 -----END PGP SIGNATURE----- Merge tag 'slab-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab Pull slab fixes from Vlastimil Babka: - Stable fixes for CONFIG_SMP=n where _nolock() allocations in NMI both at kmalloc and page allocator levels are not properly protected by the spin_trylock() semantics on !SMP (Harry Yoo) * tag 'slab-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: mm/slab: return NULL early from kmalloc_nolock() in NMI on UP mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP |
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Qi Zheng
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99ebc509ee |
mm: memcontrol: fix rcu unbalance in get_non_dying_memcg_end()
Currently, get_non_dying_memcg_start() and get_non_dying_memcg_end() both
evaluate cgroup_subsys_on_dfl(memory_cgrp_subsys) independently to
determine whether to acquire or release the RCU read lock.
However, the result of cgroup_subsys_on_dfl() can change dynamically at
runtime due to cgroup hierarchy rebinding (e.g., when the memory
controller is moved between cgroup v1 and v2 hierarchies). This can cause
the following warning:
=====================================
WARNING: bad unlock balance detected!
7.0.0-next-20260420+ #83 Tainted: G W
-------------------------------------
memcg-repro/270 is trying to release lock (rcu_read_lock) at:
[<ffffffff815f57f7>] rcu_read_unlock+0x17/0x60
but there are no more locks to release!
other info that might help us debug this:
1 lock held by memcg-repro/270:
#0: ffff888102fa2088 (vm_lock){++++}-{0:0}, at: do_user_addr_fault+0x285/0x880
stack backtrace:
CPU: 0 UID: 0 PID: 270 Comm: memcg-repro Tainted: G W 7.0.0-next-20260420+ #
Tainted: [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
<TASK>
? rcu_read_unlock+0x17/0x60
dump_stack_lvl+0x77/0xb0
print_unlock_imbalance_bug+0xe0/0xf0
? rcu_read_unlock+0x17/0x60
lock_release+0x21d/0x2a0
rcu_read_unlock+0x1c/0x60
do_pte_missing+0x233/0xb40
__handle_mm_fault+0x80e/0xcd0
handle_mm_fault+0x146/0x310
do_user_addr_fault+0x303/0x880
exc_page_fault+0x9b/0x270
asm_exc_page_fault+0x26/0x30
RIP: 0033:0x5590e4eb41ea
Code: 61 cc 66 0f 6f e0 66 0f 61 c2 66 0f db cd 66 0f 69 e2 66 0f 6f d0 66 0f 69 d4 66 0f 61 0
RSP: 002b:00007ffcad25f030 EFLAGS: 00010202
RAX: 00005590e4eb8010 RBX: 00007ffcad260f7d RCX: 00007f73c474d44d
RDX: 00005590e4eb80a0 RSI: 00005590e4eb503c RDI: 000000000000000f
RBP: 00005590e4eb70a0 R08: 0000000000000000 R09: 00007f73c483a680
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcad25f180 R14: 00005590e4eb6dd8 R15: 00007f73c4869020
</TASK>
------------[ cut here ]------------
Fix this by explicitly tracking the RCU lock state, ensuring that
rcu_read_unlock() in get_non_dying_memcg_end() is strictly paired with the
lock acquisition, regardless of any runtime rebinding events.
Link: https://lore.kernel.org/20260429073105.44472-1-qi.zheng@linux.dev
Fixes:
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David Carlier
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0fb1daf0b7 |
mm/memfd_luo: report error when restoring a folio fails mid-loop
memfd_luo_retrieve_folios() initialises err to -EIO, but the per-iteration
calls to mem_cgroup_charge(), shmem_add_to_page_cache() and
shmem_inode_acct_blocks() reuse and overwrite err. Once any iteration
completes successfully, err becomes zero.
If a later iteration's kho_restore_folio() returns NULL, the failure path
jumps to put_folios without resetting err, so the function returns 0.
The caller memfd_luo_retrieve() then takes the success path, sets
args->file and reports the restore as successful, leaving userspace with
a partially populated memfd and no indication that anything went wrong.
Set err to -EIO in the kho_restore_folio() failure branch so the error
is propagated to the caller.
Signed-off-by: David Carlier <devnexen@gmail.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Fixes:
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David Carlier
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292411fda2 |
mm/userfaultfd: detect VMA type change after copy retry in mfill_copy_folio_retry()
mfill_copy_folio_retry() drops mmap_lock for the copy_from_user() call.
During this window, the VMA can be replaced with a different type (e.g.
hugetlb), making the caller's ops pointer stale. Subsequent use of the
stale ops would dispatch into the wrong per-vma handlers.
Capture the VMA's ops via vma_uffd_ops() before dropping the lock and
compare against the current vma_uffd_ops() after re-acquiring it.
Return -EAGAIN if they differ so the operation can be retried. This
avoids comparing against the caller's ops which may have been
overridden to anon_uffd_ops for MAP_PRIVATE file-backed mappings.
Link: https://lore.kernel.org/20260424183638.196227-1-devnexen@gmail.com
Fixes:
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SeongJae Park
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f98590bc08 |
mm/damon/stat: detect and use fresh enabled value
DAMON_STAT updates 'enabled' parameter value, which represents the running
status of its kdamond, when the user explicitly requests start/stop of the
kdamond. The kdamond can, however, be stopped even if the user explicitly
requested the stop, if ctx->regions_score_histogram allocation failure at
beginning of the execution of the kdamond. Hence, if the kdamond is
stopped by the allocation failure, the value of the parameter can be
stale.
Users could show the stale value and be confused. The problem will only
rarely happen in real and common setups because the allocation is arguably
too small to fail. Also, unlike the similar bugs that are now fixed in
DAMON_RECLAIM and DAMON_LRU_SORT, kdamond can be restarted in this case,
because DAMON_STAT force-updates the enabled parameter value for user
inputs. The bug is a bug, though.
The issue stems from the fact that there are multiple events that can
change the status, and following all the events is challenging.
Dynamically detect and use the fresh status for the parameters when those
are requested.
The issue was dicovered [1] by Sashiko.
Link: https://lore.kernel.org/20260419161003.79176-4-sj@kernel.org
Link: https://lore.kernel.org/20260416040602.88665-1-sj@kernel.org [1]
Fixes:
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SeongJae Park
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b98b7ff602 |
mm/damon/lru_sort: detect and use fresh enabled and kdamond_pid values
DAMON_LRU_SORT updates 'enabled' and 'kdamond_pid' parameter values, which
represents the running status of its kdamond, when the user explicitly
requests start/stop of the kdamond. The kdamond can, however, be stopped
in events other than the explicit user request in the following three
events.
1. ctx->regions_score_histogram allocation failure at beginning of the
execution,
2. damon_commit_ctx() failure due to invalid user input, and
3. damon_commit_ctx() failure due to its internal allocation failures.
Hence, if the kdamond is stopped by the above three events, the values of
the status parameters can be stale. Users could show the stale values and
be confused. This is already bad, but the real consequence is worse.
DAMON_LRU_SORT avoids unnecessary damon_start() and damon_stop() calls
based on the 'enabled' parameter value. And the update of 'enabled'
parameter value depends on the damon_start() and damon_stop() call
results. Hence, once the kdamond has stopped by the unintentional events,
the user cannot restart the kdamond before the system reboot. For
example, the issue can be reproduced via below steps.
# cd /sys/module/damon_lru_sort/parameters
#
# # start DAMON_LRU_SORT
# echo Y > enabled
# ps -ef | grep kdamond
root 806 2 0 17:53 ? 00:00:00 [kdamond.0]
root 808 803 0 17:53 pts/4 00:00:00 grep kdamond
#
# # commit wrong input to stop kdamond withou explicit stop request
# echo 3 > addr_unit
# echo Y > commit_inputs
bash: echo: write error: Invalid argument
#
# # confirm kdamond is stopped
# ps -ef | grep kdamond
root 811 803 0 17:53 pts/4 00:00:00 grep kdamond
#
# # users casn now show stable status
# cat enabled
Y
# cat kdamond_pid
806
#
# # even after fixing the wrong parameter,
# # kdamond cannot be restarted.
# echo 1 > addr_unit
# echo Y > enabled
# ps -ef | grep kdamond
root 815 803 0 17:54 pts/4 00:00:00 grep kdamond
The problem will only rarely happen in real and common setups for the
following reasons. The allocation failures are unlikely in such setups
since those allocations are arguably too small to fail. Also sane users
on real production environments may not commit wrong input parameters.
But once it happens, the consequence is quite bad. And the bug is a bug.
The issue stems from the fact that there are multiple events that can
change the status, and following all the events is challenging.
Dynamically detect and use the fresh status for the parameters when those
are requested.
Link: https://lore.kernel.org/20260419161003.79176-3-sj@kernel.org
Fixes:
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SeongJae Park
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64a140afa5 |
mm/damon/reclaim: detect and use fresh enabled and kdamond_pid values
Patch series "mm/damon/modules: detect and use fresh status", v3.
DAMON modules including DAMON_RECLAIM, DAMON_LRU_SORT and DAMON_STAT
commonly expose the kdamond running status via their parameters. Under
certain scenarios including wrong user inputs and memory allocation
failures, those parameter values can be stale. It can confuse users. For
DAMON_RECLAIM and DAMON_LRU_SORT, it even makes the kdamond unable to be
restarted before the system reboot.
The problem comes from the fact that there are multiple events for the
status changes and it is difficult to follow up all the scenarios. Fix
the issue by detecting and using the status on demand, instead of using a
cached status that is difficult to be updated.
Patches 1-3 fix the bugs in DAMON_RECLAIM, DAMON_LRU_SORT and DAMON_STAT
in the order.
This patch (of 3):
DAMON_RECLAIM updates 'enabled' and 'kdamond_pid' parameter values, which
represents the running status of its kdamond, when the user explicitly
requests start/stop of the kdamond. The kdamond can, however, be stopped
in events other than the explicit user request in the following three
events.
1. ctx->regions_score_histogram allocation failure at beginning of the
execution,
2. damon_commit_ctx() failure due to invalid user input, and
3. damon_commit_ctx() failure due to its internal allocation failures.
Hence, if the kdamond is stopped by the above three events, the values of
the status parameters can be stale. Users could show the stale values and
be confused. This is already bad, but the real consequence is worse.
DAMON_RECLAIM avoids unnecessary damon_start() and damon_stop() calls
based on the 'enabled' parameter value. And the update of 'enabled'
parameter value depends on the damon_start() and damon_stop() call
results. Hence, once the kdamond has stopped by the unintentional events,
the user cannot restart the kdamond before the system reboot. For
example, the issue can be reproduced via below steps.
# cd /sys/module/damon_reclaim/parameters
#
# # start DAMON_RECLAIM
# echo Y > enabled
# ps -ef | grep kdamond
root 806 2 0 17:53 ? 00:00:00 [kdamond.0]
root 808 803 0 17:53 pts/4 00:00:00 grep kdamond
#
# # commit wrong input to stop kdamond withou explicit stop request
# echo 3 > addr_unit
# echo Y > commit_inputs
bash: echo: write error: Invalid argument
#
# # confirm kdamond is stopped
# ps -ef | grep kdamond
root 811 803 0 17:53 pts/4 00:00:00 grep kdamond
#
# # users casn now show stable status
# cat enabled
Y
# cat kdamond_pid
806
#
# # even after fixing the wrong parameter,
# # kdamond cannot be restarted.
# echo 1 > addr_unit
# echo Y > enabled
# ps -ef | grep kdamond
root 815 803 0 17:54 pts/4 00:00:00 grep kdamond
The problem will only rarely happen in real and common setups for the
following reasons. The allocation failures are unlikely in such setups
since those allocations are arguably too small to fail. Also sane users
on real production environments may not commit wrong input parameters.
But once it happens, the consequence is quite bad. And the bug is a bug.
The issue stems from the fact that there are multiple events that can
change the status, and following all the events is challenging.
Dynamically detect and use the fresh status for the parameters when those
are requested.
Link: https://lore.kernel.org/20260419161003.79176-1-sj@kernel.org
Link: https://lore.kernel.org/20260419161003.79176-2-sj@kernel.org
Fixes:
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SeongJae Park
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cf3b71421c |
mm/damon/sysfs-schemes: protect path kfree() with damon_sysfs_lock
damon_sysfs_quot_goal->path can be read and written by users, via DAMON
sysfs 'path' file. It can also be indirectly read, for the parameters
{on,off}line committing to DAMON. The reads for parameters committing are
protected by damon_sysfs_lock to avoid the sysfs files being destroyed
while any of the parameters are being read. But the user-driven direct
reads and writes are not protected by any lock, while the write is
deallocating the path-pointing buffer. As a result, the readers could
read the already freed buffer (user-after-free). Note that the user-reads
don't race when the same open file is used by the writer, due to kernfs's
open file locking. Nonetheless, doing the reads and writes with separate
open files would be common. Fix it by protecting both the user-direct
reads and writes with damon_sysfs_lock.
Link: https://lore.kernel.org/20260423150253.111520-3-sj@kernel.org
Fixes:
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SeongJae Park
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1e68eb96e8 |
mm/damon/sysfs-schemes: protect memcg_path kfree() with damon_sysfs_lock
Patch series "mm/damon/sysfs-schemes: fix use-after-free for [memcg_]path".
Reads of 'memcg_path' and 'path' files in DAMON sysfs interface could race
with their writes, results in use-after-free. Fix those.
This patch (of 2):
damon_sysfs_scheme_filter->mmecg_path can be read and written by users,
via DAMON sysfs memcg_path file. It can also be indirectly read, for the
parameters {on,off}line committing to DAMON. The reads for parameters
committing are protected by damon_sysfs_lock to avoid the sysfs files
being destroyed while any of the parameters are being read. But the
user-driven direct reads and writes are not protected by any lock, while
the write is deallocating the memcg_path-pointing buffer. As a result,
the readers could read the already freed buffer (user-after-free). Note
that the user-reads don't race when the same open file is used by the
writer, due to kernfs's open file locking. Nonetheless, doing the reads
and writes with separate open files would be common. Fix it by protecting
both the user-direct reads and writes with damon_sysfs_lock.
Link: https://lore.kernel.org/20260423150253.111520-1-sj@kernel.org
Link: https://lore.kernel.org/20260423150253.111520-2-sj@kernel.org
Fixes:
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