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For KPF_IDLE, folio_test_idle() check in set_ps_flags() already handles
all config cases, so remove the duplicate code in stable_page_flags() that
deals with CONFIG_PAGE_IDLE_FLAG for the 64‑bit case.
No functional change is intended.
Link: https://lore.kernel.org/20260720033021.4091944-4-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Luiz Capitulino <luizcap@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Svetly Todorov <svetly.todorov@memverge.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Since commit 304daa8132a9 ("maps4: add /proc/kpageflags interface"),
/proc/kpageflags directly operates on page->flags to determine page
status. Later, commit 177975495914 ("proc: export more page flags in
/proc/kpageflags") started using page helper functions when exposing new
flags, leading to a mix of both approaches.
For tail pages, the original code did not return corresponding status.
commit 0a71649cb724 ("/proc/kpageflags: return KPF_SLAB for slab tail
pages") and commit 832fc1de01ae ("/proc/kpageflags: return KPF_BUDDY for
"tail" buddy pages") made tail slab/buddy pages also return corresponding
status. Then commit dee3d0bef2b0 ("proc: rewrite stable_page_flags()")
made all tail pages return the same status as their head page, except for
hwpoison and mapped flags. It also cached the folio's flags and operate
on the flags directly to avoid concurrency issues if using folio_test_*()
helpers.
Since commit 476d87d6a061 ("fs: stable_page_flags(): use
snapshot_page()"), we can now safely switch to folio_test_*() helpers
instead of directly operating on flags, which is more readable and
consistent with the rest of the kernel. Only convert cfolio-specific
flags (i.e., anon, ksm, swapcache) to folio_test_*() helpers, which
reduces redundant code. Keep others unchanged due to they aren't
folio-specific flags or coverting them doesn't cleanup.
No functional change is intended.
Link: https://lore.kernel.org/20260720033021.4091944-3-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Luiz Capitulino <luizcap@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Svetly Todorov <svetly.todorov@memverge.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "cleanup for stable_page_flags()", v2.
This series cleans up stable_page_flags(), see the details in the commit
messages.
This patch (of 3):
The stable_page_flags() function currently sets page flag bits using "1 <<
KPF_xxx" for various KPF_* definitions. KPF_* may be larger than 32,
which will trigger -Wshift-count-overflow warning. All KPF_* values
currently used in "1 << KPF_xxx" are smaller than 33, so no warning is
triggered with current code.
Replace all occurrences of "1 << KPF_*" with the BIT_ULL() macro to ensure
all shifts are performed on a 64-bit unsigned type. This makes the code
robust, and safe for future extension.
No functional change is intended.
Link: https://lore.kernel.org/20260720033021.4091944-1-tujinjiang@huawei.com
Link: https://lore.kernel.org/20260720033021.4091944-2-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Luiz Capitulino <luizcap@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Svetly Todorov <svetly.todorov@memverge.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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deferred_split_queue was removed from struct pglist_data {} in commit
fafaeceb89a5 ("mm: switch deferred split shrinker to list_lru"). Remove
its description in doc as well.
Link: https://lore.kernel.org/20260721111919.22923-1-zenghui.yu@linux.dev
Signed-off-by: Zenghui Yu (Huawei) <zenghui.yu@linux.dev>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damon_apply_min_nr_regions() repeatedly split each region until its size
becomes small enough to meet the user-defined low limit of the number of
regions. The loop assumes the split operation (damon_split_region_at())
will always succeed and create the new region. But the operation could
silently fail for memory allocation failures, for example.
If such failure happens and the region was the last region, the linked
list-based next region fetching returns invalid pointer. As a result,
invalid memory dereference and corruption could happen. Even if the
corner case is handled, it imposes stress to the allocator by trying split
regions for other targets. Fix the issue by breaking all the loops for
any region split failure.
This means there could be a min_nr_regions violation. It will only rarely
happen since the allocation is arguably too small to fail. Even if it
happens, it is only temporal. damon_apply_min_nr_regions() will be called
again after the aggregation interval.
The user impact of the issue should be minor, since the allocation is
arguably too small to fail. But, it could still theoretically happen, and
the consequence is very bad.
This issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260719155442.88794-1-sj@kernel.org
Link: https://lore.kernel.org/20260717011834.120715-1-sj@kernel.org [1]
Fixes: b1029f29eb1d ("mm/damon/core: split regions for min_nr_regions")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 7.1.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Since commit 42f994b71404 ("mm/damon/core: implement scheme-specific apply
interval"), DAMOS scheme can be applied at any time. At that time,
nr_accesses may not be fully aggregated. But the quota prioritization
score is calculated using the not fully aggregated count. As a result,
the performance of DAMOS could be degraded. Fix by using
damon_nr_accesses_mvsum() instead.
The user impact of the issue is suboptimum DAMOS performance under certain
setups. Nonetheless, the bug was there from the beginning of the setup
availability. In other words, the suboptimum performance is the baseline
of the setup and hence it didn't cause regression. Also the extent of the
suboptimality was not big enough to be found from users and testers.
Still, this is a clear bug that is better to be fixed, and can be easily
fixed.
Link: https://lore.kernel.org/20260719161136.90191-1-sj@kernel.org
Fixes: 42f994b71404 ("mm/damon/core: implement scheme-specific apply interval")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.7.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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hugetlbfs_fill_super() allocates a hugepage subpool when size or min_size
mount options are specified. hugepage_new_subpool() may also reserve huge
pages for min_size.
If root dentry creation fails after the subpool is created, the failure
path frees the subpool with kfree(). This bypasses hugepage_put_subpool()
and can leave min_size reservations charged.
Use hugepage_put_subpool() on the failure path, matching the normal
put_super path.
Link: https://lore.kernel.org/20260720021900.1376309-1-chenyichong@uniontech.com
Fixes: 7ca02d0ae586 ("hugetlbfs: accept subpool min_size mount option and setup accordingly")
Signed-off-by: Yichong Chen <chenyichong@uniontech.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damon_migrate_folio_list()
In damon_migrate_folio_list(), we're redeclaring folio inside the first
while loop, but it just shadows the outer one. Since the second loop uses
the outer folio anyway, the inner declaration is pointless.
Remove it to consistently reuse the same variable throughout the
function and improve readability.
Link: https://lore.kernel.org/20260718002125.637104-1-lienze@kylinos.cn
Signed-off-by: Enze Li <lienze@kylinos.cn>
Reviewed-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damon_test_commit_target_regions_for() traverses expected values array
after damon_commit_target_regions() call. It assumes
damon_commit_target_regions() made expected number of regions. It might
not. Because the traversal is made based on the region count, it could do
out of bounds access to the expectation value array.
The consequent user impact (out-of-bound access) is quite bad. The
realistic user impact would be limited, though. It would affect only test
run setups.
Fix it by testing if the number of regions was also changed as expected
and exit early for the failure.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260718001442.87129-8-sj@kernel.org
Link: https://lore.kernel.org/20260713144757.39740-1-sj@kernel.org [1]
Fixes: 603f67eb91e0 ("mm/damon/tests/core-kunit: add damon_commit_target_regions() test")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: <stable@vger.kernel.org> # 6.19.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damos_test_commit_quota_goals_for() traverses damos quota goals after
damos_commit_quota_goals() call. It assumes damos_commit_quota_goals()
made expected numbers of goals. It might not. Because the traversal is
made based on destination struct length, it could do out of bounds access
for source expectation value array.
The consequent user impact (out-of-bound access ) is quite bad. The
realistic user impact would be limited though. It would affect only test
run setups.
Fix it by testing if the number of goals was also changed as expected and
exit early for the failure.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260718001442.87129-7-sj@kernel.org
Link: https://lore.kernel.org/20260713144757.39740-1-sj@kernel.org [1]
Fixes: d9adfb8a28e7 ("mm/damon/tests/core-kunit: add damos_commit_quota_goals() test")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: <stable@vger.kernel.org> # 6.19.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damos_test_commit_dests_for() traverse damos action destinations after
damos_commit_dests(). It assumes damos_commit_dests() made expected
numbers of destinations for source and destination structures. It might
not. Because the traversal is made based on destination struct length, it
could do out of bounds access for source value expectation.
The consequent user impact (out-of-bound access ) is quite bad. The
realistic user impact would be limited, though. It would affect only test
run setups.
Fix it by exiting early for the number of regions test failure.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260718001442.87129-6-sj@kernel.org
Link: https://lore.kernel.org/20260713144757.39740-1-sj@kernel.org [1]
Fixes: eec573b8dd65 ("mm/damon/tests/core-kunit: add damos_commit_dests() test")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: <stable@vger.kernel.org> # 6.19.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damos_test_filter_out() test checks if damos_filter_match() of an address
filter splits the region as expected under a given condition. But, the
test continued regardless of the split successes. As a result, the later
part of the test could dereference invalid pointers that returned from
damon_next_region(). Further, it could corrupt memory from
damon_destroy_region().
The consequent user impact (memory corruption) is quite bad. The
realistic user impact would be limited, though. It would affect only test
run setups.
Fix it by exiting early for the number of regions test failure.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260718001442.87129-5-sj@kernel.org
Link: https://lore.kernel.org/20260714142352.100478-1-sj@kernel.org [1]
Fixes: 26713c890875 ("mm/damon/core-test: add a unit test for __damos_filter_out()")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: <stable@vger.kernel.org> # 6.6.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damon_do_test_apply_three_regions() iterates regions after
damon_set_regions() call assuming the function would succeed at setting
the number of regions the same to the expected one. It might have failed.
In this case, __nth_region_of() in the iteration could return NULL and
NULL dereference can happen in the test.
The consequent user impact (NULL dereference) is quite bad. The realistic
user impact would be limited, though. It would affect only test run
setups.
Fix it by testing if the number of regions was also changed as expected
and exit early for the failure.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260718001442.87129-4-sj@kernel.org
Link: https://lore.kernel.org/20260713144757.39740-1-sj@kernel.org [1]
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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damon_test_split_at() test next region that is assumed to be created by
damon_split_region_at() invocation. But the split might fail. In this
case, the succeeding test may dereference invalid pointers returned by
damon_next_region().
The invalid pointer may not cause a really bad user impact, because of the
implementation detail. It would only read wrong contents in the belonging
damon_target struct. Depending on the future change of the offset from
the link header to the accessing field, this could also be really
dangerous, though. Still, the realistic user impact would be limited. It
would affect only test run setups.
Fix it by testing if the number of regions was also changed as expected
and exit early for the failure.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260718001442.87129-3-sj@kernel.org
Link: https://lore.kernel.org/20260714142352.100478-1-sj@kernel.org [1]
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/damon: fix uninitialized DAMOS field and kunit exec
expectation bugs".
Fix a few Sashiko-found unurgent bugs. Patch 1 fixes use of uninitialized
damos->last_applied field. Patches 2-7 fix DAMON kunit tests that do
invalid memory access under test failures.
The bugs are better to be fixed and eventually merged into stable@ kernel.
That said, the fixes are arguably not urgent. Patch 1 only introduces
negligible DAMOS efficiency degradation in occasional cases. Kunit fixes
could introduce quite bad consequences but those are test code that affect
only test run setups.
This patch (of 7):
Multiple DAMON regions could exist across a folio. If they fulfill the
condition to apply a DAMOS scheme, the scheme could be applied multiple
times to the folio. To avoid this, each DAMOS scheme stores the folio
that the scheme was applied to last time in the damos->last_applied field
and skips repeatedly applying the same scheme to the same folio.
The field is being used without initialization, though. Hence, the
mechanism could wrongly skip applying a scheme to a folio at the very
first time of DAMOS run.
The user impact is trivial. DAMON might unexpectedly skip applying DAMOS
action for one folio for the first time per scheme. In the DAMON's
best-effort world, this is never a real problem. No critical consequences
such as kernel panic or memory corruption happen.
It is a clear bug, though, and the fix is straightforward. Fix the issue
by initializing the field in DAMOS scheme creation function,
damon_new_scheme().
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260718001442.87129-1-sj@kernel.org
Link: https://lore.kernel.org/20260718001442.87129-2-sj@kernel.org
Link: https://lore.kernel.org/20260714055436.120034-1-sj@kernel.org [1]
Fixes: 94ba17adaba0 ("mm/damon: avoid applying DAMOS action to same entity multiple times")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: <stable@vger.kernel.org> # 6.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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split_folio_to_list_to_order() had no direct callers; its only user was
split_folio_to_order(), which always passed a NULL list. Fold it into
split_folio_to_order() and call split_huge_page_to_list_to_order()
directly.
No functional change.
Link: https://lore.kernel.org/20260716100345.473473-3-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: Usama Arif <usama.arif@linux.dev>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/huge_memory: drop dead split helper variants".
Two trivial cleanups in the folio split API, found while auditing the
split helpers for the inode UAF fix [1]:
- can_split_folio() is dead: only the !THP stub remains, no definition
under CONFIG_TRANSPARENT_HUGEPAGE and no callers. Leftover from an
earlier cleanup.
- split_folio_to_list_to_order() has no direct callers; its only user
is split_folio_to_order(), which always passes a NULL list. Fold it.
No functional change.
This patch (of 2):
can_split_folio() has no callers and no definition under
CONFIG_TRANSPARENT_HUGEPAGE; only the !THP stub remains, left behind by an
earlier cleanup. Remove it.
No functional change.
Link: https://lore.kernel.org/20260716100345.473473-1-kirill@shutemov.name
Link: https://lore.kernel.org/20260716100345.473473-2-kirill@shutemov.name
Link: https://lore.kernel.org/linux-mm/aldjhtfVByHDQXe6@thinkstation [1]
Link: https://lore.kernel.org/linux-mm/20260714122344.351895-1-kirill@shutemov.name [2]
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: Usama Arif <usama.arif@linux.dev>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Use early returns to reduce indentation and improve readability.
Link: https://lore.kernel.org/20260717091347.1144789-7-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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walk_hugetlb_range() always passes a non-NULL pte, so remove the dead NULL
check. Replace the per-page iteration loop with memset() for better
performance.
[wangkefeng.wang@huawei.com: fixup improve mincore_hugetlb()]
Link: https://lore.kernel.org/20260720124252.1483984-1-wangkefeng.wang@huawei.com
Link: https://lore.kernel.org/20260717091347.1144789-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The swap_cache_get_folio() no longer returns shadow entries, so the
xa_is_value() check is unnecessary.
Link: https://lore.kernel.org/20260717091347.1144789-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Remove ugly casts by using the more natural kmalloc/kfree allocation, also
replace GFP_USER(pointless here) with GFP_KERNEL.
Link: https://lore.kernel.org/20260717091347.1144789-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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As David pointed out, "it's hard to believe that someone depends on pages
in VM_PFNMAP to *not* be present", so remove the historical behavior that
always reports VM_PFNMAP pages as non-resident.
Adding mincore_pud_range() allows the page table walker to traverse the
full page table hierarchy without splitting a huge PUD, enabling much more
precise identification of resident pages in PFNMAP VMAs.
[wangkefeng.wang@huawei.com: address David's comments]
Link: https://lore.kernel.org/20260720124151.1483820-1-wangkefeng.wang@huawei.com
Link: https://lore.kernel.org/linux-mm/0e619d71-1c3d-4534-8376-2982c7348c31@kernel.org/
Link: https://lore.kernel.org/20260717091347.1144789-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm: mincore: misc cleanups", v3.
This series cleans up and simplifies the mincore. Most importantly, it
removes the historical special behavior that always reports VM_PFNMAP
pages as non-resident.
This patch (of 6):
Introduce the pud_is_huge() helper function to check whether a PUD is a
huge PUD or a software leaf entry. Note that, unlike PMD, PUD currently
does not support transparent migration entries or device private entries.
However, the function still includes `!pud_none()` branches to accommodate
potential future implementations.
Link: https://lore.kernel.org/20260717091347.1144789-1-wangkefeng.wang@huawei.com
Link: https://lore.kernel.org/20260717091347.1144789-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In mremap_dontunmap_partial_mapping_overwrite(), mremap() stores its
returned remapped address into remapped_mapping, while the BUG_ON
incorrectly checks dest_mapping instead.
If mremap() fails, dest_mapping still holds a valid pointer obtained from
the prior mmap() call, making this BUG_ON never trigger at all. Correct
the check to validate the actual mremap() return value stored in
remapped_mapping.
Link: https://lore.kernel.org/20260717070251.73212-1-hongfu.li@linux.dev
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The previous patch fixed this issue for the traditional LRU. The same
problem exists in MGLRU [1]: when swappiness=max (SWAPPINESS_ANON_ONLY) is
set, reclaim is expected to evict anonymous pages exclusively, but file
pages can still be reclaimed when anonymous pages cannot be reclaimed
(e.g. no swap and no demotion target).
Fix it the same way as the traditional LRU: keep returning
SWAPPINESS_ANON_ONLY in get_swappiness(), and return 0 from
get_nr_to_scan() when SWAPPINESS_ANON_ONLY is set but anon pages cannot be
reclaimed. Since get_nr_to_scan() decides how much MGLRU scans, returning
0 skips the scan entirely and avoids the useless scan work when there is
nothing eligible to reclaim.
The test result:
Before fix:
# cat /sys/kernel/mm/lru_gen/enabled
0x0007
# cat memory.stat
anon 204800
file 67108864
...
pgsteal_proactive 0
pgscan_proactive 0
# echo "64M swappiness=max" > memory.reclaim
# cat memory.stat
anon 208896
file 0
...
pgsteal_proactive 16384
pgscan_proactive 16384
After fix:
# cat memory.stat
anon 188416
file 67215360
kernel 1970176
...
pgsteal_proactive 0
pgscan_proactive 0
# echo "64M swappiness=max" > memory.reclaim
-bash: echo: write error: Resource temporarily unavailable
# cat memory.stat
anon 204800
file 67215360
...
pgsteal_proactive 0
pgscan_proactive 0
Link: https://lore.kernel.org/20260724033435.2573323-5-ridong.chen@linux.dev
Link: https://sashiko.dev/#/patchset/20260717113300.214717-1-ridong.chen@linux.dev [1]
Fixes: 68a1436bde00 ("mm: add swappiness=max arg to memory.reclaim for only anon reclaim")
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
Reviewed-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.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: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Commit 57972c78e678 ("mm/vmscan: make __node_reclaim() more generic")
moved the scan_control construction out to the callers and passed the
struct in by pointer. After that change every use of the gfp mask inside
__node_reclaim() goes through sc->gfp_mask, leaving the gfp_mask parameter
unused. Just remove the dead parameter and update the callers
accordingly. No functional change.
Link: https://lore.kernel.org/20260724033435.2573323-4-ridong.chen@linux.dev
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Qi Zheng <qi.zheng@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kairui Song <kasong@tencent.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
It has been observed that per-node proactive reclaim always returns
-EAGAIN when any error occurs. As discussed in the mailing list [1], the
interface should distinguish between cases where no reclaimable memory is
left and where another entity is concurrently using the same interface.
Propagate the real error code, consistent with how memcg proactive reclaim
handles errors.
Link: https://lore.kernel.org/20260724033435.2573323-3-ridong.chen@linux.dev
Link: https://lore.kernel.org/all/20250717235604.2atyx2aobwowpge3@offworld/T/#m3514718be82a31b05726a49da9b61fbfc69a589e [1]
Fixes: b980077899ea ("mm: introduce per-node proactive reclaim interface")
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Qi Zheng <qi.zheng@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kairui Song <kasong@tencent.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/vmscan: fix swappiness=max and clean up per-node
proactive reclaim", v4.
Fixes and one cleanup.
Patch 1 fixes "swappiness=max": the anon-only test in get_scan_count() sat
after the "cannot reclaim anon" check, so when no anon was reclaimable the
request fell back to SCAN_FILE and evicted page cache instead.
Patch 2 fixes reclaim_store() collapsing every error into -EAGAIN, so
callers can no longer tell an invalid argument from a busy interface;
propagate the real error code, matching the memcg path.
Patch 3 drops the now-unused gfp_mask parameter from __node_reclaim().
Patch 4 fixes the same "swappiness=max" issue for MGLRU.
This patch (of 4):
As Qi mentioned [1], when swappiness=max (SWAPPINESS_ANON_ONLY) is set,
the reclaim logic is expected to reclaim anonymous pages exclusively.
However, due to the current ordering of checks in get_scan_count(), file
pages may still be evicted if can_reclaim_anon_pages() returns false,
which contradicts the semantics of SWAPPINESS_ANON_ONLY.
Reproducer in a cgroup holding 64M of file cache, with no swap configured:
Before (file cache is wrongly evicted):
# cat memory.stat
anon 196608
file 67178496
pgscan_proactive 0
# echo "64M swappiness=max" > memory.reclaim
# cat memory.stat
anon 208896
file 4096 <- page cache evicted
pgsteal_proactive 16400
pgscan_proactive 16400
After (file cache is left intact):
# cat memory.stat
anon 200704
file 67178496
pgscan_proactive 0
# echo "64M swappiness=max" > memory.reclaim
-bash: echo: write error: Resource temporarily unavailable
# cat memory.stat
anon 208896
file 67178496 <- page cache untouched
pgsteal_proactive 0
pgscan_proactive 0
Fix this by bailing out early when SWAPPINESS_ANON_ONLY is set and no
anonymous pages are reclaimable, before falling back to file reclaim.
Link: https://lore.kernel.org/20260724033435.2573323-1-ridong.chen@linux.dev
Link: https://lore.kernel.org/20260724033435.2573323-2-ridong.chen@linux.dev
Link: https://lore.kernel.org/cgroups/7ddf3eee-5fe2-45f7-8614-c8936a039e04@linux.dev/ [1]
Fixes: 68a1436bde00 ("mm: add swappiness=max arg to memory.reclaim for only anon reclaim")
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
Suggested-by: Qi Zheng <qi.zheng@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Qi Zheng <qi.zheng@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kairui Song <kasong@tencent.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
mseal.o is built only for 64-bit kernels, so 32-bit kernels fall back to
sys_ni_syscall() and return -ENOSYS rather than -EPERM.
Drop architecture description in mseal.rst, since the arch feature doc has
the latest state of mseal for each architecture.
Fix the CONFIG_MSEAL_SYSTEM_MAPPINGS typo in init/Kconfig.
Link: https://lore.kernel.org/20260715131258.55499-1-leon.hwang@linux.dev
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Acked-by: Lance Yang <lance.yang@linux.dev>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Anand Moon <linux.amoon@gmail.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leon Hwang <leon.hwang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
There's no need to abstract do_mseal() any longer so put the system call
implementation in the system call declaration.
The comment around do_mseal() is strangely formatted, overly long and adds
a lot of superfluous information that the code already provides, so boil
it down to the essentials.
Link: https://lore.kernel.org/20260717-mseal-fixups-v2-3-0daa0014b813@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Commit 44f65d900698 ("binfmt_elf: mseal address zero") unconditionally
provided do_mseal() to any internal kernel caller in order to address a
corner case slated for possible removal.
It also incorrectly attempts to mseal without checking to see whether the
mapping even succeeded.
Restrict the scope to the corner case by providing mseal_mmap_page_zero()
which asserts the MMAP_PAGE_ZERO personality.
Avoid unnecessary checks in the start, end range by abstracting the actual
mseal()'ing to mseal_range() and have mseal_mmap_page_zero() call that
instead.
Also only try to seal the VMA if we mapped the VMA. This isn't strictly
necessary as the operation would error out anyway, but it's useless work
and could be problematic if me make future changes to mseal semantics.
Link: https://lore.kernel.org/20260717-mseal-fixups-v2-2-0daa0014b813@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/mseal: further cleanups", v2.
The mseal implementation is still rather confusing, so tighten things up a
little.
The only user of do_mseal() outside of the system call is the
MMAP_PAGE_ZERO process personality - retain better control over how mseal
is utilised by providing mseal_mmap_page_zero() for this instead.
The comments are overly long and confusion, so cut them down so they're a
lot clearer.
Remove confusing mm_struct params (mseal can not be used on remote mm's)
and wrap the actual system call logic into the system call declaration.
This patch (of 3):
Remove comment blocks that don't add value and eliminate any confusion
about whether or not we permit mseal()'ing of remote mm's by not passing
through an mm parameter but rather referencing current->mm in each
function.
Also while we're here, avoid an ugly goto by using an else branch, and
move local parameters declarations into reverse xmas tree order.
No functional change intended.
Link: https://lore.kernel.org/20260717-mseal-fixups-v2-0-0daa0014b813@kernel.org
Link: https://lore.kernel.org/20260717-mseal-fixups-v2-1-0daa0014b813@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
VM_BUG_ON() is out of favour and on the way to removal, since I recently
touched alloc_pages_node_noprof() I am removing that invocation, and also
removing the __folio_alloc_node_noprof() one for consistency. If this
precondition is violated, the system will soon crash anyway.
Link: https://lore.kernel.org/20260715-spin-trylock-followup-v3-4-fc4d246f705d@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Suggested-by: Zi Yan <ziy@nvidia.com>
Link: https://lore.kernel.org/all/7F866265-3F2E-4765-B9D4-9AB898A9C4AC@nvidia.com/
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Update the comment to reflect the recent change to allow flags in
gfp_nolock.
Link: https://lore.kernel.org/20260715-spin-trylock-followup-v3-3-fc4d246f705d@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reported-by: sashiko-bot@kernel.org
Link: https://sashiko.dev/#/patchset/20260703-alloc-trylock-v5-0-c87b714e19d3%40google.com?part=6
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
These comments describing the page allocator are out of date:
- __alloc_pages() is no longer a public API and has no business being
described outside of mm/.
- The `wait` variable is gone.
It may be out of date for other reasons too but this patch is just
fixing the issues that stood out.
To fix it:
- Instead of referring to a specific function, instead to "the page
allocator"
- Completely drop out-of-date details of that function's internal
behaviour, since they were irrelevant anyway.
Link: https://lore.kernel.org/20260715-spin-trylock-followup-v3-2-fc4d246f705d@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Suggested-by: Zi Yan <ziy@nvidia.com>
Link: https://lore.kernel.org/all/DJP11T5V7BDW.2FZZZ8R6LOY4I@nvidia.com/
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/page_alloc: couple of followups for recent cleanups", v3.
This patch (of 4):
As discussed in the linked patch, the there is some inconsistency between
"trylock" and "nolock" nomenclature, let's align it. Since "nolock" is
used in the public API it seems to have more mindshare so do that.
The linked patch did this for the ALLOC_ flag but forgot about FPI_.
Link: https://lore.kernel.org/20260715-spin-trylock-followup-v3-0-fc4d246f705d@google.com
Link: https://lore.kernel.org/all/20260703-alloc-trylock-v5-1-c87b714e19d3@google.com/
Link: https://lore.kernel.org/20260715-spin-trylock-followup-v3-1-fc4d246f705d@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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__free_frozen_pages() checks can_spin_trylock() before entering into the
main free_frozen_page_commit()/free_one_page() path, but before this it
can get to free_one_page() via the !pcp_allowed_order() and
MIGRATE_ISOLATE paths.
The !pcp_allowed_order() path depends on usage by callers so might not be
possible in practice. The MIGRATE_ISOLATE path probably means kernel
crashes and privilege escalation if anyone ever did memory hotplug and BPF
tracing on a PREEMPT_RT or !SMP build.
Link: https://lore.kernel.org/20260715-alloc-nolock-fixes-v1-2-fadc49952dda@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Fixes: 8c57b687e833 ("mm, bpf: Introduce free_pages_nolock()")
Reported-by: sashiko-bot@kernel.org
Closes: https://sashiko.dev/#/patchset/20260710-spin-trylock-followup-v1-0-affb5fe5ed00%40google.com?part=2
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Harry Yoo (Oracle) <harry@kernel.org>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
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>
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Patch series "mm/page_alloc: fixes for free_pages_nolock() on RT/UP".
Pre-existing bugs found by Sashiko during review of this other series:
https://lore.kernel.org/all/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com/
I have not reproduced these bugs, and I suspect there is no real-world
user that is affected by them.
This patch (of 2):
As noted in can_spin_trylock(), using this is unsafe in this context.
commit 620b46ed6ae17 ("mm/page_alloc: return NULL early from
alloc_frozen_pages_nolock() in NMI on UP") fixed this on the alloc side
but missed the free side.
Impact: If BPF programs using these features in NMI (probably tracing) are
present on non-SMP builds this might crash the kernel and is probably
exploitable by local attackers for privilege escalation.
Link: https://lore.kernel.org/20260715-alloc-nolock-fixes-v1-0-fadc49952dda@google.com
Link: https://lore.kernel.org/20260715-alloc-nolock-fixes-v1-1-fadc49952dda@google.com
Fixes: 8c57b687e833 ("mm, bpf: Introduce free_pages_nolock()")
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reported-by: sashiko-bot@kernel.org
Closes: https://sashiko.dev/#/patchset/20260703-alloc-trylock-v5-0-c87b714e19d3%40google.com?part=18
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Harry Yoo (Oracle) <harry@kernel.org>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
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>
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Add coverage for the PMD-hole case fixed by "fs/proc/task_mmu: fix
PAGEMAP_SCAN written state for PMD holes": a MAP_PRIVATE|MAP_ANON THP that
is uffd-wp'd and then dropped with MADV_DONTNEED leaves a pmd_none hole
with no page table, which PAGEMAP_SCAN must still report as written.
Factor the populate/drop/scan-both-paths sequence out of
unpopulated_scan_test() into a helper, and add unpopulated_thp_scan_test()
that reuses it with a THP.
Include <linux/mman.h> for MADV_COLLAPSE; <sys/mman.h> lacks it on older
glibc (e.g. 2.34). Same approach as commit fd5295afae91 ("selftests/mm:
hmm-tests: include linux/mman.h to access MADV_COLLAPSE").
Link: https://lore.kernel.org/aljWYfPRCVc6IB2b@thinkstation
Link: https://lore.kernel.org/20260715144234.442721-3-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Cc: Muhammad Usama Anjum <usama.anjum@arm.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Zenghui Yu <zenghui.yu@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Assisted-by: Claude:claude-fable-5
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Correct typos in mm documentation by balancing parentheses.
Link: https://lore.kernel.org/20260629161156.90213-2-manuelebner@mailbox.org
Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Vishal Moola <vishal.moola@gmail.com>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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secretmem_fault() allocates a folio with GFP_HIGHUSER and then calls
set_direct_map_invalid_noflush() without checking folio_test_highmem().
This causes a warning and process crash (vibe-coded reproducer in Link
below):
Su[ 30.071284] ------------[ cut here ]------------
ccessfully allocated and mapped 2097152000 bytes at 0x3a449000
Populating memor[ 30.074614] CPA: called for zero pte. vaddr = 0 cpa->vaddr = 0
y...
[ 30.078636] WARNING: arch/x86/mm/pat/set_memory.c:1840 at __cpa_process_fault+0x34d/0x360, CPU#5: allocate_secret/570
[ 30.084789] CPU: 5 UID: 0 PID: 570 Comm: allocate_secret Not tainted 7.1.0-14063-g4edcdefd4083-dirty #10 PREEMPTLAZY
[ 30.090937] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
[ 30.097543] EIP: __cpa_process_fault+0x34d/0x360
[ 30.100514] Code: ff ff 85 c0 0f 89 7d fe ff ff e9 3d fe ff ff 8b 03 8b 00 c7 04 24 c8 ff 64 c1 89 44 24 08 8b 45 e8 89 44 24 04 e8 53 7
a 00 00 <0f> 0b c7 45 f0 f2 ff ff ff e9 fc fc ff ff 90 8d 74 26 00 55 25 00
[ 30.110829] EAX: 00000000 EBX: f64afe98 ECX: 00000000 EDX: 00000000
[ 30.114799] ESI: 00000000 EDI: f64afe98 EBP: f64afe04 ESP: f64afdcc
[ 30.118785] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010246
[ 30.123020] CR0: 80050033 CR2: 46c48ffc CR3: 038c8000 CR4: 00000690
[ 30.127010] Call Trace:
[ 30.129078] __change_page_attr_set_clr+0x5e7/0x870
[ 30.132275] ? console_unlock+0x99/0x130
[ 30.135069] ? irq_work_queue+0x36/0x70
[ 30.137853] ? page_address+0xd3/0xf0
[ 30.140421] set_direct_map_invalid_noflush+0x52/0x60
[ 30.143782] secretmem_fault+0x128/0x210
[ 30.146560] __do_fault+0x25/0x90
[ 30.149053] handle_mm_fault+0x6d1/0xcb0
[ 30.151759] exc_page_fault+0x135/0x3b0
[ 30.154487] ? doublefault_shim+0x150/0x150
[ 30.157416] handle_exception+0x130/0x130
[ 30.160137] EIP: 0x804d29f
[ 30.162307] Code: 89 54 08 e1 89 54 08 e5 89 54 08 e9 89 54 08 ed c3 0f b6 44 24 08 89 7c 24 0c 69 c0 01 01 01 01 8b 7c 24 04 f7 c7 0f 0
0 00 00 <89> 44 0f fc 75 0e c1 e9 02 f3 ab 8b 44 24 04 8b 7c 24 0c c3 31 d2
[ 30.172936] EAX: 5a5a5a5a EBX: 00000000 ECX: 0c800000 EDX: 3a449000
[ 30.176927] ESI: 00000000 EDI: 3a449000 EBP: bfbbae18 ESP: bfbbadac
[ 30.180897] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00010246
[ 30.185161] ? doublefault_shim+0x150/0x150
[ 30.187979] ---[ end trace 0000000000000000 ]---
Bus error (core dumped) ./allocate_secret_i686 2000M
The equivalent bug was pointed out by a local Sashiko instance on
https://lore.kernel.org/all/20260410151746.61150-3-kalyazin@amazon.com/
This hasn't been reproduced it on older kernel versions but from code
inspection the bug seems to go back to the original introduction in commit
1507f51255c9f ("mm: introduce memfd_secret system call to create "secret"
memory areas"). If this configuration has always been broken, there's no
need to worry too much about feature regression here.
Nonetheless, instead of just completely disabling secretmem under
!HIGHMEM, just drop __GFP_HIGHMEM. This means that now where you
previously got a crash, instead you'll just see the secretmem process OOM.
Could secretmem just support highmem by saying "this isn't in the direct
map anyway" and bailing out before the set_direct_map_invalid_noflush()?
Maybe. That depends on requirements that are not well-defined (e.g. is
it OK that kmap_local_page() is not a NOP for those pages?), and would
require some research and deep thinking. Let's "defer" that until an
actual usecase arises.
Link: https://github.com/bjackman/limmat-kernel-nix/commit/7b2acba2d3a5ef01400d493a155beb1d135b6bb5
Link: https://lore.kernel.org/20260717-secretmem-highmem-v2-1-1f1a961ca91e@google.com
Link: https://lore.kernel.org/all/20260704192603.40aa80cf9242b77aa75e8d8d@linux-foundation.org/
Fixes: 1507f51255c9 ("mm: introduce memfd_secret system call to create "secret" memory areas")
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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damon_sysfs_apply_inputs() reads ops_id twice. It could race with
ops_id_store(). As a result, the min_region_sz could wrongly be set up.
Read it once.
The user impact is trivial. Sane users ain't update the parameter in
parallel. Even if it happens, the DAMON core layer handles the wrong
min_region_sz (!is_power_of_2()). Even if somehow the race ended up
making a min_region_sz that is different from the user's intention but
still valid, only monitoring itself runs differently than expected. No
critical consequences like kernel panic or memory corruption happen
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-7-sj@kernel.org
Link: https://lore.kernel.org/20260703172417.95426-1-sj@kernel.org [1]
Fixes: 8d009da32f13 ("mm/damon/sysfs: set damon_ctx->min_sz_region only for paddr use case")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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|
damon_sysfs_apply_inputs() reads addr_unit twice. It could race with
addr_unit_store(). As a result, the min_region_sz could wrongly be set
up. Read it once.
The user impact is trivial. Sane users ain't update the parameter in
parallel. Even if it happens, the DAMON core layer handles the wrong
min_region_sz (!is_power_of_2()). Even if somehow the race ended up
making a min_region_sz that is different from the user's intention but
still valid, only monitoring itself runs differently than expected. No
critical consequences like kernel panic or memory corruption happen.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-6-sj@kernel.org
Link: https://lore.kernel.org/20260714142950.100711-1-sj@kernel.org [1]
Fixes: 540a2aebc657 ("mm/damon/sysfs: implement addr_unit file under context dir")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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|
It can race when multiple kdamonds are being used. The problem from the
race is doubtful, but the gain from the optimization is also doubtful.
Simply drop the optimization in favor of code simplicity.
The user impact is doubtfully trivial. After all, this kind of
interference can happen only by intentional user setup. Even if it
happens, it will be rare, and the consequence is degradation of the
best-effort monitoring results. No critical consequences like kernel
panic or memory corruption happen.
The race was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-5-sj@kernel.org
Link: https://lore.kernel.org/20260621204050.10993-1-sj@kernel.org [1]
Fixes: a28397beb55b ("mm/damon: implement primitives for physical address space monitoring")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 5.16.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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The optimization can race when multiple kdamonds are running. Meanwhile,
the impact of the optimization is quite doubtful. Just remove it.
The user impact of the issue should be quite trivial. After all, the race
can happen only when the user intentionally setup DAMON in the way. Even
if it happens, it would be rare and only degrade the best-effort
monitoring results. No critical consequences like kernel panic or memory
corruption happen.
The race possibility was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-4-sj@kernel.org
Link: https://lore.kernel.org/20260621204050.10993-1-sj@kernel.org [1]
Fixes: 3f49584b262c ("mm/damon: implement primitives for the virtual memory address spaces")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
KUNIT_EXPECT_EQ() does not abort the execution of test code when the
expectation is not met. But damon_test_merge_regions_of() code after its
initial KUNIT_EXPECT_EQ() call assumes the expectation is met. It does a
per-region test with a hard-coded number of regions that is correct only
if the expectation was met. As a result, __nth_region_of() could return
NULL, and the test code can dereference NULL pointers. Fix the issue by
catching the expectation failure and skip the per-region tests.
The user impact on realistic setups should be negligible, as it is a unit
test.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-3-sj@kernel.org
Link: https://lore.kernel.org/20260710144937.26981-1-sj@kernel.org [1]
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon: unurgent fixes for infinite loop, NULL de-ref and
races", v1.1.
Sashiko found a few issues in DAMON that could cause infinite loop, NULL
dereference and monitoring results degradation. The first two sounds
scary but the infinite loop happens only under unreasonable user setup.
The NULL dereference is only in a unit test. Monitoring results
degradation is trivial since it is only best-effort, and those happens
from only unlikely races. Still those are bugs that better to fix if
possible. Fix those.
This patch (of 6):
Due to online parameter update like events, the number of DAMON regions
could be higher than the user-set upper limit. kdamond_merge_regions()
repeats merge regions until the number meets the limit, while doubling the
merge threshold up to the theoretical maximum threshold. It is tried only
up to the theoretical maximum threshold because even the aggressive
merging can fail from reducing the number of regions under the
user-defined upper limit. For example, there could be many user-defined
non-contiguous regions that cannot be merged.
The threshold based loop break condition is evaluated by comparing the
threshold for the next merging try against the theoretical maximum
threshold. If max_thres is larger than UINT_MAX / 2, doubling the
threshold could make it overflow, and bypass the loop break condition. In
the case, if the number of regions cannot be reduced under the upper limit
like explained above, the loop will run infinitely.
Prevent the case by doing the break condition check before doubling the
threshold. Also, prevent the threshold exceeding the maximum threshold,
as it could overflow and apply the wrong merge threshold.
This issue is unlikely to occur in real world, since having the max_thres
higher than UINT_MAX / 2 require unrealistically large aggregation
intervals compared to the sampling interval. Also, it requires an
unrealistically large number of uncontiguous regions setup. Nonetheless,
the consequence is bad and the fix is simple.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-1-sj@kernel.org
Link: https://lore.kernel.org/20260715031002.108504-2-sj@kernel.org
Link: https://lore.kernel.org/20260709145425.96247-1-sj@kernel.org [1]
Fixes: 310d6c15e910 ("mm/damon/core: merge regions aggressively when max_nr_regions is unmet")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.10.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
There is only one caller, get_page_from_freelist(), and it does not make
any use of the reason for skipping the reclaim, nor does it make any
distinction between a full and partially successful reclaim.
Therefore, node_reclaim() can simply return the number of pages that have
been reclaimed, same as __node_reclaim(), and the NODE_RECLAIM_xxx macros
can be removed.
There is one small change of behavior when __node_reclaim() was attempted
but returned zero. The allocation now skips the zone immediately; before
this patch, the zone watermarks were checked first. I believe it was an
oversight rather than intention, because the chances that zone watermark
is OK after __node_reclaim() did not reclaim any pages are very close to
zero.
Originally, I was looking for occurences of NODE_RECLAIM_SOME and
NODE_RECLAIM_SUCCESS, but I couldn't find any. That's because they are
typecast from the result of a relational operator. This seemed a bit
fragile, so I dug a bit deeper and came up with this proposed cleanup.
Link: https://lore.kernel.org/20260714132300.2136018-1-ptesarik@suse.com
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
'ops', 'probes', 'adaptive_targets', 'schemes', and 'rnd_state' fields of
damon_ctx are intended to be used by only the DAMON core layer. However,
those are mistakenly not marked as private. Mark as private.
Link: https://lore.kernel.org/20260714143544.101305-11-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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damon_ctx->ops field is intended to be used by only the DAMON core layer.
DAMON_SYSFS is directly reading the field to find if it is for physical
address monitoring, though. Use the API function for the purpose,
damon_target_has_pid(), instead.
Link: https://lore.kernel.org/20260714143544.101305-10-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
