commit 2030dddf95 upstream.
When truncating a large swap entry, shmem_free_swap() returns 0 when the
entry's index doesn't match the given index due to lookup alignment. The
failure fallback path checks if the entry crosses the end border and
aborts when it happens, so truncate won't erase an unexpected entry or
range. But one scenario was ignored.
When `index` points to the middle of a large swap entry, and the large
swap entry doesn't go across the end border, find_get_entries() will
return that large swap entry as the first item in the batch with
`indices[0]` equal to `index`. The entry's base index will be smaller
than `indices[0]`, so shmem_free_swap() will fail and return 0 due to the
"base < index" check. The code will then call shmem_confirm_swap(), get
the order, check if it crosses the END boundary (which it doesn't), and
retry with the same index.
The next iteration will find the same entry again at the same index with
same indices, leading to an infinite loop.
Fix this by retrying with a round-down index, and abort if the index is
smaller than the truncate range.
Link: https://lkml.kernel.org/r/aXo6ltB5iqAKJzY8@KASONG-MC4
Fixes: 809bc86517 ("mm: shmem: support large folio swap out")
Fixes: 8a1968bd99 ("mm/shmem, swap: fix race of truncate and swap entry split")
Signed-off-by: Kairui Song <kasong@tencent.com>
Reported-by: Chris Mason <clm@meta.com>
Closes: https://lore.kernel.org/linux-mm/20260128130336.727049-1-clm@meta.com/
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8a1968bd99 upstream.
The helper for shmem swap freeing is not handling the order of swap
entries correctly. It uses xa_cmpxchg_irq to erase the swap entry, but it
gets the entry order before that using xa_get_order without lock
protection, and it may get an outdated order value if the entry is split
or changed in other ways after the xa_get_order and before the
xa_cmpxchg_irq.
And besides, the order could grow and be larger than expected, and cause
truncation to erase data beyond the end border. For example, if the
target entry and following entries are swapped in or freed, then a large
folio was added in place and swapped out, using the same entry, the
xa_cmpxchg_irq will still succeed, it's very unlikely to happen though.
To fix that, open code the Xarray cmpxchg and put the order retrieval and
value checking in the same critical section. Also, ensure the order won't
exceed the end border, skip it if the entry goes across the border.
Skipping large swap entries crosses the end border is safe here. Shmem
truncate iterates the range twice, in the first iteration,
find_lock_entries already filtered such entries, and shmem will swapin the
entries that cross the end border and partially truncate the folio (split
the folio or at least zero part of it). So in the second loop here, if we
see a swap entry that crosses the end order, it must at least have its
content erased already.
I observed random swapoff hangs and kernel panics when stress testing
ZSWAP with shmem. After applying this patch, all problems are gone.
Link: https://lkml.kernel.org/r/20260120-shmem-swap-fix-v3-1-3d33ebfbc057@tencent.com
Fixes: 809bc86517 ("mm: shmem: support large folio swap out")
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Chris Li <chrisl@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 057a6f2632 upstream.
When a hugetlb folio is being poisoned again, try_memory_failure_hugetlb()
passed head pfn to kill_accessing_process(), that is not right. The
precise pfn of the poisoned page should be used in order to determine the
precise vaddr as the SIGBUS payload.
This issue has already been taken care of in the normal path, that is,
hwpoison_user_mappings(), see [1][2]. Further more, for [3] to work
correctly in the hugetlb repoisoning case, it's essential to inform VM the
precise poisoned page, not the head page.
[1] https://lkml.kernel.org/r/20231218135837.3310403-1-willy@infradead.org
[2] https://lkml.kernel.org/r/20250224211445.2663312-1-jane.chu@oracle.com
[3] https://lore.kernel.org/lkml/20251116013223.1557158-1-jiaqiyan@google.com/
Link: https://lkml.kernel.org/r/20260120232234.3462258-2-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Chris Mason <clm@meta.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: William Roche <william.roche@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a0f3c0845a upstream.
commit 8b47299a41 ("mm, swap: mark swap address space ro and add context
debug check") made the swap address space read-only. It may lead to
kernel panic if arch_prepare_to_swap returns a failure under heavy memory
pressure as follows,
el1_abort+0x40/0x64
el1h_64_sync_handler+0x48/0xcc
el1h_64_sync+0x84/0x88
errseq_set+0x4c/0xb8 (P)
__filemap_set_wb_err+0x20/0xd0
shrink_folio_list+0xc20/0x11cc
evict_folios+0x1520/0x1be4
try_to_shrink_lruvec+0x27c/0x3dc
shrink_one+0x9c/0x228
shrink_node+0xb3c/0xeac
do_try_to_free_pages+0x170/0x4f0
try_to_free_pages+0x334/0x534
__alloc_pages_direct_reclaim+0x90/0x158
__alloc_pages_slowpath+0x334/0x588
__alloc_frozen_pages_noprof+0x224/0x2fc
__folio_alloc_noprof+0x14/0x64
vma_alloc_zeroed_movable_folio+0x34/0x44
do_pte_missing+0xad4/0x1040
handle_mm_fault+0x4a4/0x790
do_page_fault+0x288/0x5f8
do_translation_fault+0x38/0x54
do_mem_abort+0x54/0xa8
Restore swap address space as not ro to avoid the panic.
Link: https://lkml.kernel.org/r/20260116062535.306453-2-robin.kuo@mediatek.com
Fixes: 8b47299a41 ("mm, swap: mark swap address space ro and add context debug check")
Signed-off-by: robin.kuo <robin.kuo@mediatek.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: andrew.yang <andrew.yang@mediatek.com>
Cc: AngeloGiaocchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Mathias Brugger <matthias.bgg@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Qun-wei Lin <Qun-wei.Lin@mediatek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a148a20401 upstream.
When a newly poisoned subpage ends up in an already poisoned hugetlb
folio, 'num_poisoned_pages' is incremented, but the per node ->mf_stats is
not. Fix the inconsistency by designating action_result() to update them
both.
While at it, define __get_huge_page_for_hwpoison() return values in terms
of symbol names for better readibility. Also rename
folio_set_hugetlb_hwpoison() to hugetlb_update_hwpoison() since the
function does more than the conventional bit setting and the fact three
possible return values are expected.
Link: https://lkml.kernel.org/r/20260120232234.3462258-1-jane.chu@oracle.com
Fixes: 18f41fa616 ("mm: memory-failure: bump memory failure stats to pglist_data")
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Chris Mason <clm@meta.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: William Roche <william.roche@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 870ff19251 upstream.
Randomize the KFENCE freelist during pool initialization to make
allocation patterns less predictable. This is achieved by shuffling the
order in which metadata objects are added to the freelist using
get_random_u32_below().
Additionally, ensure the error path correctly calculates the address range
to be reset if initialization fails, as the address increment logic has
been moved to a separate loop.
Link: https://lkml.kernel.org/r/20260120161510.3289089-1-pimyn@google.com
Fixes: 0ce20dd840 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Pimyn Girgis <pimyn@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Ernesto Martnez Garca <ernesto.martinezgarcia@tugraz.at>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9b47d4eea3 upstream.
A KASAN warning can be triggered when vrealloc() changes the requested
size to a value that is not aligned to KASAN_GRANULE_SIZE.
------------[ cut here ]------------
WARNING: CPU: 2 PID: 1 at mm/kasan/shadow.c:174 kasan_unpoison+0x40/0x48
...
pc : kasan_unpoison+0x40/0x48
lr : __kasan_unpoison_vmalloc+0x40/0x68
Call trace:
kasan_unpoison+0x40/0x48 (P)
vrealloc_node_align_noprof+0x200/0x320
bpf_patch_insn_data+0x90/0x2f0
convert_ctx_accesses+0x8c0/0x1158
bpf_check+0x1488/0x1900
bpf_prog_load+0xd20/0x1258
__sys_bpf+0x96c/0xdf0
__arm64_sys_bpf+0x50/0xa0
invoke_syscall+0x90/0x160
Introduce a dedicated kasan_vrealloc() helper that centralizes KASAN
handling for vmalloc reallocations. The helper accounts for KASAN granule
alignment when growing or shrinking an allocation and ensures that partial
granules are handled correctly.
Use this helper from vrealloc_node_align_noprof() to fix poisoning logic.
[ryabinin.a.a@gmail.com: move kasan_enabled() check, fix build]
Link: https://lkml.kernel.org/r/20260119144509.32767-1-ryabinin.a.a@gmail.com
Link: https://lkml.kernel.org/r/20260113191516.31015-1-ryabinin.a.a@gmail.com
Fixes: d699440f58 ("mm: fix vrealloc()'s KASAN poisoning logic")
Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Reported-by: Maciej Żenczykowski <maze@google.com>
Reported-by: <joonki.min@samsung-slsi.corp-partner.google.com>
Closes: https://lkml.kernel.org/r/CANP3RGeuRW53vukDy7WDO3FiVgu34-xVJYkfpm08oLO3odYFrA@mail.gmail.com
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 3b617fd3d3 ]
The is_mergeable_anon_vma() function uses vmg->middle as the source VMA.
However when merging a new VMA, this field is NULL.
In all cases except mremap(), the new VMA will either be newly established
and thus lack an anon_vma, or will be an expansion of an existing VMA thus
we do not care about whether VMA is CoW'd or not.
In the case of an mremap(), we can end up in a situation where we can
accidentally allow an unfaulted/faulted merge with a VMA that has been
forked, violating the general rule that we do not permit this for reasons
of anon_vma lock scalability.
Now we have the ability to be aware of the fact we are copying a VMA and
also know which VMA that is, we can explicitly check for this, so do so.
This is pertinent since commit 879bca0a2c ("mm/vma: fix incorrectly
disallowed anonymous VMA merges"), as this patch permits unfaulted/faulted
merges that were previously disallowed running afoul of this issue.
While we are here, vma_had_uncowed_parents() is a confusing name, so make
it simple and rename it to vma_is_fork_child().
Link: https://lkml.kernel.org/r/6e2b9b3024ae1220961c8b81d74296d4720eaf2b.1767638272.git.lorenzo.stoakes@oracle.com
Fixes: 879bca0a2c ("mm/vma: fix incorrectly disallowed anonymous VMA merges")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Jeongjun Park <aha310510@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: Yeoreum Yun <yeoreum.yun@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ with upstream commit 61f67c230a backported, this simply applied correctly. Built + tested ]
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ upstream commit 61f67c230a ]
Patch series "mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted
merge", v2.
Commit 879bca0a2c ("mm/vma: fix incorrectly disallowed anonymous VMA
merges") introduced the ability to merge previously unavailable VMA merge
scenarios.
However, it is handling merges incorrectly when it comes to mremap() of a
faulted VMA adjacent to an unfaulted VMA. The issues arise in three
cases:
1. Previous VMA unfaulted:
copied -----|
v
|-----------|.............|
| unfaulted |(faulted VMA)|
|-----------|.............|
prev
2. Next VMA unfaulted:
copied -----|
v
|.............|-----------|
|(faulted VMA)| unfaulted |
|.............|-----------|
next
3. Both adjacent VMAs unfaulted:
copied -----|
v
|-----------|.............|-----------|
| unfaulted |(faulted VMA)| unfaulted |
|-----------|.............|-----------|
prev next
This series fixes each of these cases, and introduces self tests to assert
that the issues are corrected.
I also test a further case which was already handled, to assert that my
changes continues to correctly handle it:
4. prev unfaulted, next faulted:
copied -----|
v
|-----------|.............|-----------|
| unfaulted |(faulted VMA)| faulted |
|-----------|.............|-----------|
prev next
This bug was discovered via a syzbot report, linked to in the first patch
in the series, I confirmed that this series fixes the bug.
I also discovered that we are failing to check that the faulted VMA was
not forked when merging a copied VMA in cases 1-3 above, an issue this
series also addresses.
I also added self tests to assert that this is resolved (and confirmed
that the tests failed prior to this).
I also cleaned up vma_expand() as part of this work, renamed
vma_had_uncowed_parents() to vma_is_fork_child() as the previous name was
unduly confusing, and simplified the comments around this function.
This patch (of 4):
Commit 879bca0a2c ("mm/vma: fix incorrectly disallowed anonymous VMA
merges") introduced the ability to merge previously unavailable VMA merge
scenarios.
The key piece of logic introduced was the ability to merge a faulted VMA
immediately next to an unfaulted VMA, which relies upon dup_anon_vma() to
correctly handle anon_vma state.
In the case of the merge of an existing VMA (that is changing properties
of a VMA and then merging if those properties are shared by adjacent
VMAs), dup_anon_vma() is invoked correctly.
However in the case of the merge of a new VMA, a corner case peculiar to
mremap() was missed.
The issue is that vma_expand() only performs dup_anon_vma() if the target
(the VMA that will ultimately become the merged VMA): is not the next VMA,
i.e. the one that appears after the range in which the new VMA is to be
established.
A key insight here is that in all other cases other than mremap(), a new
VMA merge either expands an existing VMA, meaning that the target VMA will
be that VMA, or would have anon_vma be NULL.
Specifically:
* __mmap_region() - no anon_vma in place, initial mapping.
* do_brk_flags() - expanding an existing VMA.
* vma_merge_extend() - expanding an existing VMA.
* relocate_vma_down() - no anon_vma in place, initial mapping.
In addition, we are in the unique situation of needing to duplicate
anon_vma state from a VMA that is neither the previous or next VMA being
merged with.
dup_anon_vma() deals exclusively with the target=unfaulted, src=faulted
case. This leaves four possibilities, in each case where the copied VMA
is faulted:
1. Previous VMA unfaulted:
copied -----|
v
|-----------|.............|
| unfaulted |(faulted VMA)|
|-----------|.............|
prev
target = prev, expand prev to cover.
2. Next VMA unfaulted:
copied -----|
v
|.............|-----------|
|(faulted VMA)| unfaulted |
|.............|-----------|
next
target = next, expand next to cover.
3. Both adjacent VMAs unfaulted:
copied -----|
v
|-----------|.............|-----------|
| unfaulted |(faulted VMA)| unfaulted |
|-----------|.............|-----------|
prev next
target = prev, expand prev to cover.
4. prev unfaulted, next faulted:
copied -----|
v
|-----------|.............|-----------|
| unfaulted |(faulted VMA)| faulted |
|-----------|.............|-----------|
prev next
target = prev, expand prev to cover. Essentially equivalent to 3, but
with additional requirement that next's anon_vma is the same as the copied
VMA's. This is covered by the existing logic.
To account for this very explicitly, we introduce
vma_merge_copied_range(), which sets a newly introduced vmg->copied_from
field, then invokes vma_merge_new_range() which handles the rest of the
logic.
We then update the key vma_expand() function to clean up the logic and
make what's going on clearer, making the 'remove next' case less special,
before invoking dup_anon_vma() unconditionally should we be copying from a
VMA.
Note that in case 3, the if (remove_next) ... branch will be a no-op, as
next=src in this instance and src is unfaulted.
In case 4, it won't be, but since in this instance next=src and it is
faulted, this will have required tgt=faulted, src=faulted to be
compatible, meaning that next->anon_vma == vmg->copied_from->anon_vma, and
thus a single dup_anon_vma() of next suffices to copy anon_vma state for
the copied-from VMA also.
If we are copying from a VMA in a successful merge we must _always_
propagate anon_vma state.
This issue can be observed most directly by invoked mremap() to move
around a VMA and cause this kind of merge with the MREMAP_DONTUNMAP flag
specified.
This will result in unlink_anon_vmas() being called after failing to
duplicate anon_vma state to the target VMA, which results in the anon_vma
itself being freed with folios still possessing dangling pointers to the
anon_vma and thus a use-after-free bug.
This bug was discovered via a syzbot report, which this patch resolves.
We further make a change to update the mergeable anon_vma check to assert
the copied-from anon_vma did not have CoW parents, as otherwise
dup_anon_vma() might incorrectly propagate CoW ancestors from the next VMA
in case 4 despite the anon_vma's being identical for both VMAs.
Link: https://lkml.kernel.org/r/cover.1767638272.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/b7930ad2b1503a657e29fe928eb33061d7eadf5b.1767638272.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Fixes: 879bca0a2c ("mm/vma: fix incorrectly disallowed anonymous VMA merges")
Reported-by: syzbot+b165fc2e11771c66d8ba@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/694a2745.050a0220.19928e.0017.GAE@google.com/
Reported-by: syzbot+5272541ccbbb14e2ec30@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/694e3dc6.050a0220.35954c.0066.GAE@google.com/
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Jeongjun Park <aha310510@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Yeoreum Yun <yeoreum.yun@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ updated to account for lack of sticky VMA flags + built, tested confirmed working ]
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 3937027cae ]
Ever since we stopped using the page count to detect shared PMD page
tables, these comments are outdated.
The only reason we have to flush the TLB early is because once we drop the
i_mmap_rwsem, the previously shared page table could get freed (to then
get reallocated and used for other purpose). So we really have to flush
the TLB before that could happen.
So let's simplify the comments a bit.
The "If we unshared PMDs, the TLB flush was not recorded in mmu_gather."
part introduced as in commit a4a118f2ee ("hugetlbfs: flush TLBs
correctly after huge_pmd_unshare") was confusing: sure it is recorded in
the mmu_gather, otherwise tlb_flush_mmu_tlbonly() wouldn't do anything.
So let's drop that comment while at it as well.
We'll centralize these comments in a single helper as we rework the code
next.
Link: https://lkml.kernel.org/r/20251223214037.580860-3-david@kernel.org
Fixes: 59d9094df3 ("mm: hugetlb: independent PMD page table shared count")
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Uschakow, Stanislav" <suschako@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b7880cb166 upstream.
Syzbot has found a deadlock (analyzed by Lance Yang):
1) Task (5749): Holds folio_lock, then tries to acquire i_mmap_rwsem(read lock).
2) Task (5754): Holds i_mmap_rwsem(write lock), then tries to acquire
folio_lock.
migrate_pages()
-> migrate_hugetlbs()
-> unmap_and_move_huge_page() <- Takes folio_lock!
-> remove_migration_ptes()
-> __rmap_walk_file()
-> i_mmap_lock_read() <- Waits for i_mmap_rwsem(read lock)!
hugetlbfs_fallocate()
-> hugetlbfs_punch_hole() <- Takes i_mmap_rwsem(write lock)!
-> hugetlbfs_zero_partial_page()
-> filemap_lock_hugetlb_folio()
-> filemap_lock_folio()
-> __filemap_get_folio <- Waits for folio_lock!
The migration path is the one taking locks in the wrong order according to
the documentation at the top of mm/rmap.c. So expand the scope of the
existing i_mmap_lock to cover the calls to remove_migration_ptes() too.
This is (mostly) how it used to be after commit c0d0381ade. That was
removed by 336bf30eb7 for both file & anon hugetlb pages when it should
only have been removed for anon hugetlb pages.
Link: https://lkml.kernel.org/r/20260109041345.3863089-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Fixes: 336bf30eb7 ("hugetlbfs: fix anon huge page migration race")
Reported-by: syzbot+2d9c96466c978346b55f@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/68e9715a.050a0220.1186a4.000d.GAE@google.com
Debugged-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Jann Horn <jannh@google.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 16aca2c98a upstream.
Commit 2b7226af73 ("mm/memcg: make memory.reclaim interface generic")
moved proactive reclaim logic from memory.reclaim handler to a generic
user_proactive_reclaim() helper to be used for per-node proactive reclaim.
However, user_proactive_reclaim() was only defined under CONFIG_NUMA, with
a stub always returning 0 otherwise. This broke memory.reclaim on
!CONFIG_NUMA configs, causing it to report success without actually
attempting reclaim.
Move the definition of user_proactive_reclaim() outside CONFIG_NUMA, and
instead define a stub for __node_reclaim() in the !CONFIG_NUMA case.
__node_reclaim() is only called from user_proactive_reclaim() when a write
is made to sys/devices/system/node/nodeX/reclaim, which is only defined
with CONFIG_NUMA.
Link: https://lkml.kernel.org/r/20260116205247.928004-1-yosry.ahmed@linux.dev
Fixes: 2b7226af73 ("mm/memcg: make memory.reclaim interface generic")
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a8682d500f upstream.
PMD page table unsharing no longer touches the refcount of a PMD page
table. Also, it is not about dropping the refcount of a "PMD page" but
the "PMD page table".
Let's just simplify by saying that the PMD page table was unmapped,
consequently also unmapping the folio that was mapped into this page.
This code should be deduplicated in the future.
Link: https://lkml.kernel.org/r/20251223214037.580860-4-david@kernel.org
Fixes: 59d9094df3 ("mm: hugetlb: independent PMD page table shared count")
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Uschakow, Stanislav" <suschako@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 99a3e3a1cf upstream.
On PREEMPT_RT kernels, local_lock becomes a sleeping lock. The current
check in kmalloc_nolock() only verifies we're not in NMI or hard IRQ
context, but misses the case where preemption is disabled.
When a BPF program runs from a tracepoint with preemption disabled
(preempt_count > 0), kmalloc_nolock() proceeds to call
local_lock_irqsave() which attempts to acquire a sleeping lock,
triggering:
BUG: sleeping function called from invalid context
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6128
preempt_count: 2, expected: 0
Fix this by checking !preemptible() on PREEMPT_RT, which directly
expresses the constraint that we cannot take a sleeping lock when
preemption is disabled. This encompasses the previous checks for NMI
and hard IRQ contexts while also catching cases where preemption is
disabled.
Fixes: af92793e52 ("slab: Introduce kmalloc_nolock() and kfree_nolock().")
Reported-by: syzbot+b1546ad4a95331b2101e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b1546ad4a95331b2101e
Signed-off-by: Swaraj Gaikwad <swarajgaikwad1925@gmail.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260113150639.48407-1-swarajgaikwad1925@gmail.co
Cc: <stable@vger.kernel.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 038a102535 upstream.
The kernel test robot has reported:
BUG: spinlock trylock failure on UP on CPU#0, kcompactd0/28
lock: 0xffff888807e35ef0, .magic: dead4ead, .owner: kcompactd0/28, .owner_cpu: 0
CPU: 0 UID: 0 PID: 28 Comm: kcompactd0 Not tainted 6.18.0-rc5-00127-ga06157804399 #1 PREEMPT 8cc09ef94dcec767faa911515ce9e609c45db470
Call Trace:
<IRQ>
__dump_stack (lib/dump_stack.c:95)
dump_stack_lvl (lib/dump_stack.c:123)
dump_stack (lib/dump_stack.c:130)
spin_dump (kernel/locking/spinlock_debug.c:71)
do_raw_spin_trylock (kernel/locking/spinlock_debug.c:?)
_raw_spin_trylock (include/linux/spinlock_api_smp.h:89 kernel/locking/spinlock.c:138)
__free_frozen_pages (mm/page_alloc.c:2973)
___free_pages (mm/page_alloc.c:5295)
__free_pages (mm/page_alloc.c:5334)
tlb_remove_table_rcu (include/linux/mm.h:? include/linux/mm.h:3122 include/asm-generic/tlb.h:220 mm/mmu_gather.c:227 mm/mmu_gather.c:290)
? __cfi_tlb_remove_table_rcu (mm/mmu_gather.c:289)
? rcu_core (kernel/rcu/tree.c:?)
rcu_core (include/linux/rcupdate.h:341 kernel/rcu/tree.c:2607 kernel/rcu/tree.c:2861)
rcu_core_si (kernel/rcu/tree.c:2879)
handle_softirqs (arch/x86/include/asm/jump_label.h:36 include/trace/events/irq.h:142 kernel/softirq.c:623)
__irq_exit_rcu (arch/x86/include/asm/jump_label.h:36 kernel/softirq.c:725)
irq_exit_rcu (kernel/softirq.c:741)
sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1052)
</IRQ>
<TASK>
RIP: 0010:_raw_spin_unlock_irqrestore (arch/x86/include/asm/preempt.h:95 include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194)
free_pcppages_bulk (mm/page_alloc.c:1494)
drain_pages_zone (include/linux/spinlock.h:391 mm/page_alloc.c:2632)
__drain_all_pages (mm/page_alloc.c:2731)
drain_all_pages (mm/page_alloc.c:2747)
kcompactd (mm/compaction.c:3115)
kthread (kernel/kthread.c:465)
? __cfi_kcompactd (mm/compaction.c:3166)
? __cfi_kthread (kernel/kthread.c:412)
ret_from_fork (arch/x86/kernel/process.c:164)
? __cfi_kthread (kernel/kthread.c:412)
ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
</TASK>
Matthew has analyzed the report and identified that in drain_page_zone()
we are in a section protected by spin_lock(&pcp->lock) and then get an
interrupt that attempts spin_trylock() on the same lock. The code is
designed to work this way without disabling IRQs and occasionally fail the
trylock with a fallback. However, the SMP=n spinlock implementation
assumes spin_trylock() will always succeed, and thus it's normally a
no-op. Here the enabled lock debugging catches the problem, but otherwise
it could cause a corruption of the pcp structure.
The problem has been introduced by commit 5749077415 ("mm/page_alloc:
leave IRQs enabled for per-cpu page allocations"). The pcp locking scheme
recognizes the need for disabling IRQs to prevent nesting spin_trylock()
sections on SMP=n, but the need to prevent the nesting in spin_lock() has
not been recognized. Fix it by introducing local wrappers that change the
spin_lock() to spin_lock_iqsave() with SMP=n and use them in all places
that do spin_lock(&pcp->lock).
[vbabka@suse.cz: add pcp_ prefix to the spin_lock_irqsave wrappers, per Steven]
Link: https://lkml.kernel.org/r/20260105-fix-pcp-up-v1-1-5579662d2071@suse.cz
Fixes: 5749077415 ("mm/page_alloc: leave IRQs enabled for per-cpu page allocations")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202512101320.e2f2dd6f-lkp@intel.com
Analyzed-by: Matthew Wilcox <willy@infradead.org>
Link: https://lore.kernel.org/all/aUW05pyc9nZkvY-1@casper.infradead.org/
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fc4b909c36 upstream.
It is possible for pcp->count - pcp->high to exceed pcp->batch by a lot.
When this happens, we should perform batching to ensure that
free_pcppages_bulk isn't called with too many pages to free at once and
starve out other threads that need the pcp or zone lock.
Since we are still only freeing the difference between the initial
pcp->count and pcp->high values, there should be no change to how many
pages are freed.
Link: https://lkml.kernel.org/r/20251014145011.3427205-3-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Suggested-by: Chris Mason <clm@fb.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Co-developed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 038a102535 ("mm/page_alloc: prevent pcp corruption with SMP=n")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0acc67c403 upstream.
Patch series "mm/page_alloc: Batch callers of free_pcppages_bulk", v5.
Motivation & Approach
=====================
While testing workloads with high sustained memory pressure on large
machines in the Meta fleet (1Tb memory, 316 CPUs), we saw an unexpectedly
high number of softlockups. Further investigation showed that the zone
lock in free_pcppages_bulk was being held for a long time, and was called
to free 2k+ pages over 100 times just during boot.
This causes starvation in other processes for the zone lock, which can
lead to the system stalling as multiple threads cannot make progress
without the locks. We can see these issues manifesting as warnings:
[ 4512.591979] rcu: INFO: rcu_sched self-detected stall on CPU
[ 4512.604370] rcu: 20-....: (9312 ticks this GP) idle=a654/1/0x4000000000000000 softirq=309340/309344 fqs=5426
[ 4512.626401] rcu: hardirqs softirqs csw/system
[ 4512.638793] rcu: number: 0 145 0
[ 4512.651177] rcu: cputime: 30 10410 174 ==> 10558(ms)
[ 4512.666657] rcu: (t=21077 jiffies g=783665 q=1242213 ncpus=316)
While these warnings don't indicate a crash or a kernel panic, they do
point to the underlying issue of lock contention. To prevent starvation
in both locks, batch the freeing of pages using pcp->batch.
Because free_pcppages_bulk is called with the pcp lock and acquires the
zone lock, relinquishing and reacquiring the locks are only effective when
both of them are broken together (unless the system was built with queued
spinlocks). Thus, instead of modifying free_pcppages_bulk to break both
locks, batch the freeing from its callers instead.
A similar fix has been implemented in the Meta fleet, and we have seen
significantly less softlockups.
Testing
=======
The following are a few synthetic benchmarks, made on three machines. The
first is a large machine with 754GiB memory and 316 processors.
The second is a relatively smaller machine with 251GiB memory and 176
processors. The third and final is the smallest of the three, which has 62GiB
memory and 36 processors.
On all machines, I kick off a kernel build with -j$(nproc).
Negative delta is better (faster compilation).
Large machine (754GiB memory, 316 processors)
make -j$(nproc)
+------------+---------------+-----------+
| Metric (s) | Variation (%) | Delta(%) |
+------------+---------------+-----------+
| real | 0.8070 | - 1.4865 |
| user | 0.2823 | + 0.4081 |
| sys | 5.0267 | -11.8737 |
+------------+---------------+-----------+
Medium machine (251GiB memory, 176 processors)
make -j$(nproc)
+------------+---------------+----------+
| Metric (s) | Variation (%) | Delta(%) |
+------------+---------------+----------+
| real | 0.2806 | +0.0351 |
| user | 0.0994 | +0.3170 |
| sys | 0.6229 | -0.6277 |
+------------+---------------+----------+
Small machine (62GiB memory, 36 processors)
make -j$(nproc)
+------------+---------------+----------+
| Metric (s) | Variation (%) | Delta(%) |
+------------+---------------+----------+
| real | 0.1503 | -2.6585 |
| user | 0.0431 | -2.2984 |
| sys | 0.1870 | -3.2013 |
+------------+---------------+----------+
Here, variation is the coefficient of variation, i.e. standard deviation
/ mean.
Based on these results, it seems like there are varying degrees to how
much lock contention this reduces. For the largest and smallest machines
that I ran the tests on, it seems like there is quite some significant
reduction. There is also some performance increases visible from
userspace.
Interestingly, the performance gains don't scale with the size of the
machine, but rather there seems to be a dip in the gain there is for the
medium-sized machine. One possible theory is that because the high
watermark depends on both memory and the number of local CPUs, what
impacts zone contention the most is not these individual values, but
rather the ratio of mem:processors.
This patch (of 5):
Currently, refresh_cpu_vm_stats returns an int, indicating how many
changes were made during its updates. Using this information, callers
like vmstat_update can heuristically determine if more work will be done
in the future.
However, all of refresh_cpu_vm_stats's callers either (a) ignore the
result, only caring about performing the updates, or (b) only care about
whether changes were made, but not *how many* changes were made.
Simplify the code by returning a bool instead to indicate if updates
were made.
In addition, simplify fold_diff and decay_pcp_high to return a bool
for the same reason.
Link: https://lkml.kernel.org/r/20251014145011.3427205-1-joshua.hahnjy@gmail.com
Link: https://lkml.kernel.org/r/20251014145011.3427205-2-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Chris Mason <clm@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 038a102535 ("mm/page_alloc: prevent pcp corruption with SMP=n")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e37d5a2d60 upstream.
Introduce a new IOMMU interface to flush IOTLB paging cache entries for
the CPU kernel address space. This interface is invoked from the x86
architecture code that manages combined user and kernel page tables,
specifically before any kernel page table page is freed and reused.
This addresses the main issue with vfree() which is a common occurrence
and can be triggered by unprivileged users. While this resolves the
primary problem, it doesn't address some extremely rare case related to
memory unplug of memory that was present as reserved memory at boot, which
cannot be triggered by unprivileged users. The discussion can be found at
the link below.
Enable SVA on x86 architecture since the IOMMU can now receive
notification to flush the paging cache before freeing the CPU kernel page
table pages.
Link: https://lkml.kernel.org/r/20251022082635.2462433-9-baolu.lu@linux.intel.com
Link: https://lore.kernel.org/linux-iommu/04983c62-3b1d-40d4-93ae-34ca04b827e5@intel.com/
Co-developed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Suggested-by: Jann Horn <jannh@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yi Lai <yi1.lai@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5ba2f0a155 upstream.
This introduces a conditional asynchronous mechanism, enabled by
CONFIG_ASYNC_KERNEL_PGTABLE_FREE. When enabled, this mechanism defers the
freeing of pages that are used as page tables for kernel address mappings.
These pages are now queued to a work struct instead of being freed
immediately.
This deferred freeing allows for batch-freeing of page tables, providing a
safe context for performing a single expensive operation (TLB flush) for a
batch of kernel page tables instead of performing that expensive operation
for each page table.
Link: https://lkml.kernel.org/r/20251022082635.2462433-8-baolu.lu@linux.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasant Hegde <vasant.hegde@amd.com>
Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yi Lai <yi1.lai@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9814cc832b upstream.
When a context DAMON sysfs directory setup is failed after setup of attrs/
directory, subdirectories of attrs/ directory are not cleaned up. As a
result, DAMON sysfs interface is nearly broken until the system reboots,
and the memory for the unremoved directory is leaked.
Cleanup the directories under such failures.
Link: https://lkml.kernel.org/r/20251225023043.18579-3-sj@kernel.org
Fixes: c951cd3b89 ("mm/damon: implement a minimal stub for sysfs-based DAMON interface")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: chongjiapeng <jiapeng.chong@linux.alibaba.com>
Cc: <stable@vger.kernel.org> # 5.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a24ca8ebb0 upstream.
Patch series "mm/damon/sysfs: free setup failures generated zombie sub-sub
dirs".
Some DAMON sysfs directory setup functions generates its sub and sub-sub
directories. For example, 'monitoring_attrs/' directory setup creates
'intervals/' and 'intervals/intervals_goal/' directories under
'monitoring_attrs/' directory. When such sub-sub directories are
successfully made but followup setup is failed, the setup function should
recursively clean up the subdirectories.
However, such setup functions are only dereferencing sub directory
reference counters. As a result, under certain setup failures, the
sub-sub directories keep having non-zero reference counters. It means the
directories cannot be removed like zombies, and the memory for the
directories cannot be freed.
The user impact of this issue is limited due to the following reasons.
When the issue happens, the zombie directories are still taking the path.
Hence attempts to generate the directories again will fail, without
additional memory leak. This means the upper bound memory leak is
limited. Nonetheless this also implies controlling DAMON with a feature
that requires the setup-failed sysfs files will be impossible until the
system reboots.
Also, the setup operations are quite simple. The certain failures would
hence only rarely happen, and are difficult to artificially trigger.
This patch (of 4):
When attrs/ DAMON sysfs directory setup is failed after setup of
intervals/ directory, intervals/intervals_goal/ directory is not cleaned
up. As a result, DAMON sysfs interface is nearly broken until the system
reboots, and the memory for the unremoved directory is leaked.
Cleanup the directory under such failures.
Link: https://lkml.kernel.org/r/20251225023043.18579-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20251225023043.18579-2-sj@kernel.org
Fixes: 8fbbcbeaaf ("mm/damon/sysfs: implement intervals tuning goal directory")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: chongjiapeng <jiapeng.chong@linux.alibaba.com>
Cc: <stable@vger.kernel.org> # 6.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 392b3d9d59 upstream.
When a DAMOS-scheme DAMON sysfs directory setup fails after setup of
access_pattern/ directory, subdirectories of access_pattern/ directory are
not cleaned up. As a result, DAMON sysfs interface is nearly broken until
the system reboots, and the memory for the unremoved directory is leaked.
Cleanup the directories under such failures.
Link: https://lkml.kernel.org/r/20251225023043.18579-5-sj@kernel.org
Fixes: 9bbb820a5b ("mm/damon/sysfs: support DAMOS quotas")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: chongjiapeng <jiapeng.chong@linux.alibaba.com>
Cc: <stable@vger.kernel.org> # 5.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dc7e1d75fd upstream.
When a DAMOS-scheme DAMON sysfs directory setup fails after setup of
quotas/ directory, subdirectories of quotas/ directory are not cleaned up.
As a result, DAMON sysfs interface is nearly broken until the system
reboots, and the memory for the unremoved directory is leaked.
Cleanup the directories under such failures.
Link: https://lkml.kernel.org/r/20251225023043.18579-4-sj@kernel.org
Fixes: 1b32234ab0 ("mm/damon/sysfs: support DAMOS watermarks")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: chongjiapeng <jiapeng.chong@linux.alibaba.com>
Cc: <stable@vger.kernel.org> # 5.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f9132fbc2e upstream.
If damon_call() is executed against a DAMON context that is not running,
the function returns error while keeping the damon_call_control object
linked to the context's call_controls list. Let's suppose the object is
deallocated after the damon_call(), and yet another damon_call() is
executed against the same context. The function tries to add the new
damon_call_control object to the call_controls list, which still has the
pointer to the previous damon_call_control object, which is deallocated.
As a result, use-after-free happens.
This can actually be triggered using the DAMON sysfs interface. It is not
easily exploitable since it requires the sysfs write permission and making
a definitely weird file writes, though. Please refer to the report for
more details about the issue reproduction steps.
Fix the issue by making two changes. Firstly, move the final
kdamond_call() for cancelling all existing damon_call() requests from
terminating DAMON context to be done before the ctx->kdamond reset. This
makes any code that sees NULL ctx->kdamond can safely assume the context
may not access damon_call() requests anymore. Secondly, let damon_call()
to cleanup the damon_call_control objects that were added to the
already-terminated DAMON context, before returning the error.
Link: https://lkml.kernel.org/r/20251231012315.75835-1-sj@kernel.org
Fixes: 004ded6bee ("mm/damon: accept parallel damon_call() requests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: JaeJoon Jung <rgbi3307@gmail.com>
Closes: https://lore.kernel.org/20251224094401.20384-1-rgbi3307@gmail.com
Cc: <stable@vger.kernel.org> # 6.17.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b9efe36b5e upstream.
When page isolation loops indefinitely during memory offline, reading
/proc/sys/vm/percpu_pagelist_high_fraction blocks on pcp_batch_high_lock,
causing hung task warnings.
Make procfs reads lock-free since percpu_pagelist_high_fraction is a
simple integer with naturally atomic reads, writers still serialize via
the mutex.
This prevents hung task warnings when reading the procfs file during
long-running memory offline operations.
[akpm@linux-foundation.org: add comment, per Michal]
Link: https://lkml.kernel.org/r/aS_y9AuJQFydLEXo@tiehlicka
Link: https://lkml.kernel.org/r/20251201060009.1420792-1-aboorvad@linux.ibm.com
Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 590b13669b upstream.
crypto_alloc_acomp_node() may return ERR_PTR(), but the fail path checks
only for NULL and can pass an error pointer to crypto_free_acomp(). Use
IS_ERR_OR_NULL() to only free valid acomp instances.
Link: https://lkml.kernel.org/r/20251231074638.2564302-1-pbutsykin@cloudlinux.com
Fixes: 779b9955f6 ("mm: zswap: move allocations during CPU init outside the lock")
Signed-off-by: Pavel Butsykin <pbutsykin@cloudlinux.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f46c26f1bc upstream.
The 'numa_nodes_parsed' is defined in <asm/numa.h> but this file
is not included in mm/numa_memblks.c (build x86_64) so add this
to the incldues to fix the following sparse warning:
mm/numa_memblks.c:13:12: warning: symbol 'numa_nodes_parsed' was not declared. Should it be static?
Link: https://lkml.kernel.org/r/20260108101539.229192-1-ben.dooks@codethink.co.uk
Fixes: 8748270821 ("mm: introduce numa_memblks")
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4795d205d7 upstream.
kmsan_free_page() is called by the page allocator's free_pages_prepare()
during page freeing. Its job is to poison all the memory covered by the
page. It can be called with an order-0 page, a compound high-order page
or a non-compound high-order page. But page_size() only works for order-0
and compound pages. For a non-compound high-order page it will
incorrectly return PAGE_SIZE.
The implication is that the tail pages of a high-order non-compound page
do not get poisoned at free, so any invalid access while they are free
could go unnoticed. It looks like the pages will be poisoned again at
allocation time, so that would bookend the window.
Fix this by using the order parameter to calculate the size.
Link: https://lkml.kernel.org/r/20260104134348.3544298-1-ryan.roberts@arm.com
Fixes: b073d7f8ae ("mm: kmsan: maintain KMSAN metadata for page operations")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Alexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 269031b15c upstream.
Commit 7ffb791423 ("x86/kaslr: Reduce KASLR entropy on most x86 systems")
is too narrow. The effect being mitigated in that commit is caused by
ZONE_DEVICE which PCI_P2PDMA has a dependency. ZONE_DEVICE, in general,
lets any physical address be added to the direct-map. I.e. not only ACPI
hotplug ranges, CXL Memory Windows, or EFI Specific Purpose Memory, but
also any PCI MMIO range for the DEVICE_PRIVATE and PCI_P2PDMA cases. Update
the mitigation, limit KASLR entropy, to apply in all ZONE_DEVICE=y cases.
Distro kernels typically have PCI_P2PDMA=y, so the practical exposure of
this problem is limited to the PCI_P2PDMA=n case.
A potential path to recover entropy would be to walk ACPI and determine the
limits for hotplug and PCI MMIO before kernel_randomize_memory(). On
smaller systems that could yield some KASLR address bits. This needs
additional investigation to determine if some limited ACPI table scanning
can happen this early without an open coded solution like
arch/x86/boot/compressed/acpi.c needs to deploy.
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Fixes: 7ffb791423 ("x86/kaslr: Reduce KASLR entropy on most x86 systems")
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Tested-by: Yasunori Goto <y-goto@fujitsu.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://patch.msgid.link/692e08b2516d4_261c1100a3@dwillia2-mobl4.notmuch
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
damon_test_split_regions_of() is assuming all dynamic memory allocation in
it will succeed. Those are indeed likely in the real use cases since
those allocations are too small to fail, but theoretically those could
fail. In the case, inappropriate memory access can happen. Fix it by
appropriately cleanup pre-allocated memory and skip the execution of the
remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-9-sj@kernel.org
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit eded254cb6)
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a76a5ae2c6 upstream.
The page_owner_stack_fops->open() callback invokes seq_open_private(),
therefore its corresponding ->release() callback must call
seq_release_private(). Otherwise it will cause a memory leak of struct
stack_print_ctx.
Link: https://lkml.kernel.org/r/20251219074232.136482-1-ranxiaokai627@163.com
Fixes: 765973a098 ("mm,page_owner: display all stacks and their count")
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Elver <elver@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6a0e5b3338 upstream.
A KASAN tag mismatch, possibly causing a kernel panic, can be observed on
systems with a tag-based KASAN enabled and with multiple NUMA nodes. It
was reported on arm64 and reproduced on x86. It can be explained in the
following points:
1. There can be more than one virtual memory chunk.
2. Chunk's base address has a tag.
3. The base address points at the first chunk and thus inherits
the tag of the first chunk.
4. The subsequent chunks will be accessed with the tag from the
first chunk.
5. Thus, the subsequent chunks need to have their tag set to
match that of the first chunk.
Use the new vmalloc flag that disables random tag assignment in
__kasan_unpoison_vmalloc() - pass the same random tag to all the
vm_structs by tagging the pointers before they go inside
__kasan_unpoison_vmalloc(). Assigning a common tag resolves the pcpu
chunk address mismatch.
[akpm@linux-foundation.org: use WARN_ON_ONCE(), per Andrey]
Link: https://lkml.kernel.org/r/CA+fCnZeuGdKSEm11oGT6FS71_vGq1vjq-xY36kxVdFvwmag2ZQ@mail.gmail.com
[maciej.wieczor-retman@intel.com: remove unneeded pr_warn()]
Link: https://lkml.kernel.org/r/919897daaaa3c982a27762a2ee038769ad033991.1764945396.git.m.wieczorretman@pm.me
Link: https://lkml.kernel.org/r/873821114a9f722ffb5d6702b94782e902883fdf.1764874575.git.m.wieczorretman@pm.me
Fixes: 1d96320f8d ("kasan, vmalloc: add vmalloc tagging for SW_TAGS")
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: Kees Cook <kees@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org> [6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6f13db031e upstream.
A KASAN tag mismatch, possibly causing a kernel panic, can be observed
on systems with a tag-based KASAN enabled and with multiple NUMA nodes.
It was reported on arm64 and reproduced on x86. It can be explained in
the following points:
1. There can be more than one virtual memory chunk.
2. Chunk's base address has a tag.
3. The base address points at the first chunk and thus inherits
the tag of the first chunk.
4. The subsequent chunks will be accessed with the tag from the
first chunk.
5. Thus, the subsequent chunks need to have their tag set to
match that of the first chunk.
Refactor code by reusing __kasan_unpoison_vmalloc in a new helper in
preparation for the actual fix.
Link: https://lkml.kernel.org/r/eb61d93b907e262eefcaa130261a08bcb6c5ce51.1764874575.git.m.wieczorretman@pm.me
Fixes: 1d96320f8d ("kasan, vmalloc: add vmalloc tagging for SW_TAGS")
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: Kees Cook <kees@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org> [6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 007f5da43b upstream.
Patch series "kasan: vmalloc: Fixes for the percpu allocator and
vrealloc", v3.
Patches fix two issues related to KASAN and vmalloc.
The first one, a KASAN tag mismatch, possibly resulting in a kernel panic,
can be observed on systems with a tag-based KASAN enabled and with
multiple NUMA nodes. Initially it was only noticed on x86 [1] but later a
similar issue was also reported on arm64 [2].
Specifically the problem is related to how vm_structs interact with
pcpu_chunks - both when they are allocated, assigned and when pcpu_chunk
addresses are derived.
When vm_structs are allocated they are unpoisoned, each with a different
random tag, if vmalloc support is enabled along the KASAN mode. Later
when first pcpu chunk is allocated it gets its 'base_addr' field set to
the first allocated vm_struct. With that it inherits that vm_struct's
tag.
When pcpu_chunk addresses are later derived (by pcpu_chunk_addr(), for
example in pcpu_alloc_noprof()) the base_addr field is used and offsets
are added to it. If the initial conditions are satisfied then some of the
offsets will point into memory allocated with a different vm_struct. So
while the lower bits will get accurately derived the tag bits in the top
of the pointer won't match the shadow memory contents.
The solution (proposed at v2 of the x86 KASAN series [3]) is to unpoison
the vm_structs with the same tag when allocating them for the per cpu
allocator (in pcpu_get_vm_areas()).
The second one reported by syzkaller [4] is related to vrealloc and
happens because of random tag generation when unpoisoning memory without
allocating new pages. This breaks shadow memory tracking and needs to
reuse the existing tag instead of generating a new one. At the same time
an inconsistency in used flags is corrected.
This patch (of 3):
Syzkaller reported a memory out-of-bounds bug [4]. This patch fixes two
issues:
1. In vrealloc the KASAN_VMALLOC_VM_ALLOC flag is missing when
unpoisoning the extended region. This flag is required to correctly
associate the allocation with KASAN's vmalloc tracking.
Note: In contrast, vzalloc (via __vmalloc_node_range_noprof)
explicitly sets KASAN_VMALLOC_VM_ALLOC and calls
kasan_unpoison_vmalloc() with it. vrealloc must behave consistently --
especially when reusing existing vmalloc regions -- to ensure KASAN can
track allocations correctly.
2. When vrealloc reuses an existing vmalloc region (without allocating
new pages) KASAN generates a new tag, which breaks tag-based memory
access tracking.
Introduce KASAN_VMALLOC_KEEP_TAG, a new KASAN flag that allows reusing the
tag already attached to the pointer, ensuring consistent tag behavior
during reallocation.
Pass KASAN_VMALLOC_KEEP_TAG and KASAN_VMALLOC_VM_ALLOC to the
kasan_unpoison_vmalloc inside vrealloc_node_align_noprof().
Link: https://lkml.kernel.org/r/cover.1765978969.git.m.wieczorretman@pm.me
Link: https://lkml.kernel.org/r/38dece0a4074c43e48150d1e242f8242c73bf1a5.1764874575.git.m.wieczorretman@pm.me
Link: https://lore.kernel.org/all/e7e04692866d02e6d3b32bb43b998e5d17092ba4.1738686764.git.maciej.wieczor-retman@intel.com/ [1]
Link: https://lore.kernel.org/all/aMUrW1Znp1GEj7St@MiWiFi-R3L-srv/ [2]
Link: https://lore.kernel.org/all/CAPAsAGxDRv_uFeMYu9TwhBVWHCCtkSxoWY4xmFB_vowMbi8raw@mail.gmail.com/ [3]
Link: https://syzkaller.appspot.com/bug?extid=997752115a851cb0cf36 [4]
Fixes: a0309faf1c ("mm: vmalloc: support more granular vrealloc() sizing")
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Co-developed-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reported-by: syzbot+997752115a851cb0cf36@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68e243a2.050a0220.1696c6.007d.GAE@google.com/T/
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3e5c4a1a17 upstream.
damon_test_commit_filter() is assuming all dynamic memory allocation in it
will succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-15-sj@kernel.org
Fixes: f6a4a150f1 ("mm/damon/tests/core-kunit: add damos_commit_filter test")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [6.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 915a2453d8 upstream.
damon_test_set_attrs() is assuming all dynamic memory allocation in it
will succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-13-sj@kernel.org
Fixes: aa13779be6 ("mm/damon/core-test: add a test for damon_set_attrs()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [6.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4f835f4e8c upstream.
damon_test_ops_registration() is assuming all dynamic memory allocation in
it will succeed. Those are indeed likely in the real use cases since
those allocations are too small to fail, but theoretically those could
fail. In the case, inappropriate memory access can happen. Fix it by
appropriately cleanup pre-allocated memory and skip the execution of the
remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-10-sj@kernel.org
Fixes: 4f540f5ab4 ("mm/damon/core-test: add a kunit test case for ops registration")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [5.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d14d5671e7 upstream.
damon_test_filter_out() is assuming all dynamic memory allocation in it
will succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-16-sj@kernel.org
Fixes: 26713c8908 ("mm/damon/core-test: add a unit test for __damos_filter_out()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [6.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 84be856cc8 upstream.
damon_test_set_filters_default_reject() is assuming all dynamic memory
allocation in it will succeed. Those are indeed likely in the real use
cases since those allocations are too small to fail, but theoretically
those could fail. In the case, inappropriate memory access can happen.
Fix it by appropriately cleanup pre-allocated memory and skip the
execution of the remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-17-sj@kernel.org
Fixes: 094fb14913 ("mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [6.16+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8cf298c01b upstream.
damon_test_update_monitoring_result() is assuming all dynamic memory
allocation in it will succeed. Those are indeed likely in the real use
cases since those allocations are too small to fail, but theoretically
those could fail. In the case, inappropriate memory access can happen.
Fix it by appropriately cleanup pre-allocated memory and skip the
execution of the remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-12-sj@kernel.org
Fixes: f4c978b659 ("mm/damon/core-test: add a test for damon_update_monitoring_results()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [6.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 74d5969995 upstream.
damon_test_set_regions() is assuming all dynamic memory allocation in it
will succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-11-sj@kernel.org
Fixes: 62f409560e ("mm/damon/core-test: test damon_set_regions")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3d443dd29a upstream.
damon_test_merge_two() is assuming all dynamic memory allocation in it
will succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-7-sj@kernel.org
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0998d27572 upstream.
damon_test_merge_regions_of() is assuming all dynamic memory allocation in
it will succeed. Those are indeed likely in the real use cases since
those allocations are too small to fail, but theoretically those could
fail. In the case, inappropriate memory access can happen. Fix it by
appropriately cleanup pre-allocated memory and skip the execution of the
remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-8-sj@kernel.org
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f79f2fc44e upstream.
damon_test_aggregate() is assuming all dynamic memory allocation in it
will succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-5-sj@kernel.org
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fafe953de2 upstream.
damon_test_target() is assuming all dynamic memory allocation in it will
succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-4-sj@kernel.org
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e16fdd4f75 upstream.
damon_test_regions() is assuming all dynamic memory allocation in it will
succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-3-sj@kernel.org
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5e80d73f22 upstream.
damon_test_split_at() is assuming all dynamic memory allocation in it will
succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-6-sj@kernel.org
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kairui Song
Hao Ge
Jane Chu
robin.kuo
Pimyn Girgis
Andrey Ryabinin
Lorenzo Stoakes
David Hildenbrand (Red Hat)
jianyun.gao
Matthew Wilcox (Oracle)
Yosry Ahmed
Swaraj Gaikwad
Vlastimil Babka
Joshua Hahn
Lu Baolu
Dave Hansen
SeongJae Park
Aboorva Devarajan
Pavel Butsykin
Ben Dooks
Ryan Roberts
Dan Williams
Ran Xiaokai
Alexander Gordeev
Maciej Wieczor-Retman
Jiayuan Chen