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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"13 hotfixes. All are cc:stable. 11 are for MM. All are singletons -
please see the changelogs for details"
* tag 'mm-hotfixes-stable-2026-07-27-14-18' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
fs/proc/task_mmu: fix PAGEMAP_SCAN written state for PMD holes
mm/hugetlb: fix list corruption in allocate_file_region_entries()
mm: mglru: fix stale batch updates after memcg reparenting
selftest: fix headers in fclog.c
ocfs2: fix boundary check in ocfs2_check_dir_entry() to use buffer offset
mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()
mm/util: don't read __page_2 for order-1 folios in snapshot_page()
mm/hugetlb: fix swap entry corruption when clearing uffd-wp at fork()
mm: migrate_device: fix pte_pfn/pte_dirty called on non-present PTE
fs/proc/task_mmu: fix PAGEMAP_SCAN written state for unpopulated ptes
userfaultfd: wait on source PMD during UFFDIO_MOVE
lib: test_hmm: use device devt for coherent device range selection
mm/vmstat: fold stranded per-cpu node stats when a node comes online
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Don't return the return value of down_read_killable() (0) when a ptrace
access check fails, return -EACCES as intended.
Reported-by: Magnus Lindholm <linmag7@gmail.com>
Closes: https://lore.kernel.org/r/20260706170735.2941493-1-linmag7@gmail.com
Fixes: 6650527444da ("proc: protect ptrace_may_access() with exec_update_lock (part 1)")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://patch.msgid.link/20260706-procfs-ns-eacces-fix-v1-1-a69ab14c02e6@google.com
Tested-by: Magnus Lindholm <linmag7@gmail.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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PAGEMAP_SCAN reports an unpopulated PTE in a uffd-wp VMA as written, but a
range with no page table at all -- a PMD hole -- is skipped:
pagemap_scan_pte_hole() tests p->cur_vma_category, which never carries
PAGE_IS_WRITTEN, so the hole is neither reported nor (under
PM_SCAN_WP_MATCHING) armed.
In a uffd-wp VMA, WP_UNPOPULATED installs uffd-wp markers when protecting
a range, allocating page tables as needed, so an unpopulated slot is
treated as written -- see the pte_none() handling in
pagemap_page_category(). A missing marker therefore means the range was
zapped, e.g. via MADV_DONTNEED. This applies to anon and shmem VMAs.
An anonymous THP is write-protected in place as a huge PMD, so a full-PMD
MADV_DONTNEED clears it to pmd_none -- a hole with no page table -- and
pagemap_scan_pte_hole() misses it. For a MAP_PRIVATE|MAP_ANON mapping
MADV_DONTNEED has fill-with-zeros semantics, so a write-tracking
checkpoint/migration tool (e.g. CRIU) treats the range as unchanged and
keeps its previous contents; after restore or live migration the process
reads stale data instead of zeroes -- data corruption.
Report a hole in a non-hugetlb uffd-wp VMA as written, matching the
pte_none handling in pagemap_page_category(); the existing
PM_SCAN_WP_MATCHING path then arms it via uffd_wp_range().
hugetlb is excluded: pagemap_hugetlb_category() reports an empty hugetlb
entry (huge_pte_none) as not-written, unlike pagemap_page_category(),
which reports pte_none as written. pagemap_scan_pte_hole() fires for a
hugetlb slot only when it has no page table; keeping that not-written
matches how an allocated-but-empty hugetlb entry reads, so the hole and
the empty-entry cases agree within the VMA.
Link: https://lore.kernel.org/20260715144234.442721-2-kirill@shutemov.name
Fixes: 2bad466cc9d9 ("mm/uffd: UFFD_FEATURE_WP_UNPOPULATED")
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Reported-by: Sashiko AI review <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260707151349.92143-1-kirill@shutemov.name
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
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>
Cc: Zenghui Yu <zenghui.yu@linux.dev>
Assisted-by: Claude:claude-fable-5
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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PAGEMAP_SCAN reports an unpopulated pte differently depending on which
path serves the request. The PAGE_IS_WRITTEN fast path in
pagemap_scan_pmd_entry() reports a pte_none as written (and, under
PM_SCAN_WP_MATCHING, arms a marker); pagemap_page_category() returns 0 for
the same pte_none. A request that cannot take the fast path (an extra
category bit, category_anyof_mask or category_inverted) therefore reports
the pte as clean and skips arming it.
A range that was populated and then MADV_DONTNEED'd reads as written via
one mask and clean via another, and in the latter case is not re-armed for
the next round -- an incremental-dump consumer (e.g. CRIU) using a richer
mask drops the zapped range and stops tracking writes to it.
Report pte_none as written in pagemap_page_category() too. A pte_none
carries no uffd-wp marker, i.e. it is not write-protected -- the same
condition under which the present and swap cases already report
PAGE_IS_WRITTEN. The fast path applies no VMA test, so neither does this.
The hugetlb and fully-unpopulated-PMD (no page table) scans have no
PAGE_IS_WRITTEN fast path, so they do not exhibit the per-entry divergence
and are left unchanged.
Add a pagemap_ioctl selftest that populates a range, drops it with
MADV_DONTNEED, and checks that the fast path and the generic
(category_anyof_mask) path both report every page written.
Link: https://lore.kernel.org/20260707151349.92143-1-kirill@shutemov.name
Fixes: 12f6b01a0bcb ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag")
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
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: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Assisted-by: Claude:claude-fable-5
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"20 hotfixes. 17 are for MM. 12 are cc:stable and the remaining 8
address post-7.1 issues or aren't considered suitable for backporting.
Two patches from SJ addresses a couple of quite old DAMON issues. And
two patches from Yichong Chen fixes tools/virtio build issues. The
remaining patches are singletons"
* tag 'mm-hotfixes-stable-2026-07-06-17-49' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
tools/include: include stdint.h for SIZE_MAX in overflow.h
tools/virtio: add missing compat definitions for vhost_net_test
mm: do file ownership checks with the proper mount idmap
samples/damon/mtier: fail early if address range parameters are invalid
mm: a second pagecache maintainer
mm/damon: add a kernel-doc comment for damon_ctx->rnd_state
mm/damon: add a kernel-doc comment for damon_ctx->probes
mailmap: add entries for Radu Rendec
selftests/mm: hmm-tests: include linux/mman.h to access MADV_COLLAPSE
selftests/mm: pagemap_ioctl: use the correct page size for transact_test()
fs/proc: fix KPF_KSM reported for all anonymous pages
mm: page_ext: add count limit to page_ext_iter_next to prevent invalid PFN access
mm/damon/ops-common: handle extreme intervals in damon_hot_score()
MAINTAINERS: add Lance as an rmap reviewer
mm/compaction: handle free_pages_prepare() properly in compaction_free()
mm/damon/sysfs-schemes: put stats for scheme_add_dirs() internal error
mm/damon/sysfs-schemes: fix dir put orders in access_pattern_add_dirs()
mm: shrinker: fix NULL pointer dereference in debugfs
mm: shrinker: fix shrinker_info teardown race with expansion
selftests/mm: fix ksft_process_madv.sh test category
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Reading /proc/kpageflags for any anonymous page returns KPF_KSM set, even
when KSM is not in use. As a result, tools misclassify all anonymous
pages as KSM merged.
In stable_page_flags(), if the page is anonymous, then use (mapping &
FOLIO_MAPPING_KSM) check to identify if the anonymous page is KSM page.
However, FOLIO_MAPPING_KSM is FOLIO_MAPPING_ANON | FOLIO_MAPPING_ANON_KSM,
(mapping & FOLIO_MAPPING_KSM) check returns true for all anonymous pages.
To fix it, use FOLIO_MAPPING_ANON_KSM instead.
Link: https://lore.kernel.org/20260629033122.774318-1-tujinjiang@huawei.com
Link: https://lore.kernel.org/20260626013252.2846774-1-tujinjiang@huawei.com
Fixes: dee3d0bef2b0 ("proc: rewrite stable_page_flags()")
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Xu Xin <xu.xin16@zte.com.cn>
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: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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proc_register() increments the parent directory's link count for every
entry it registers, while remove_proc_entry() and remove_proc_subtree()
decrement it only when the removed entry is a directory. Regular files
thus inflate the parent's count while they exist, and leak one link
permanently on every create and remove cycle.
For example, /proc/bus/pci/00 with twenty-two device files and no
subdirectories reports nlink 24 instead of 2, and SR-IOV VF enable
and disable cycles, each creating and removing the VF config space
entries under /proc/bus/pci/<bus>, inflate the link count of that
directory without bound.
Before commit e06689bf5701 ("proc: change ->nlink under
proc_subdir_lock"), the increment lived in proc_mkdir_data() and
proc_create_mount_point(), and was therefore applied only to
directories. Moving it into proc_register() to bring it under
proc_subdir_lock dropped the S_ISDIR check.
Thus, move the nlink accounting into pde_subdir_insert() and
pde_erase(), only updating it for directories in both, so the link
count is always changed together with the directory entry itself.
Fixes: e06689bf5701 ("proc: change ->nlink under proc_subdir_lock")
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Link: https://patch.msgid.link/20260613211005.921692-1-kwilczynski@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- "taskstats: fix TGID dead-thread stat retention" (Yiyang Chen)
Fix a taskstats TGID aggregation bug where fields added in the TGID
query path were not preserved after thread exit, and adds a kselftest
covering the regression.
- "lib/tests: string_helpers: Slight improvements" (Andy Shevchenko)
Improve lib/tests/string_helpers_kunit.c a little
- "lib/base64: decode fixes" (Josh Law)
Address minor issues in lib/base64.c
- "selftests/filelock: Make output more kselftestish" (Mark Brown)
Make the output from the ofdlocks test a bit easier for tooling to
work with. Also ignore the generated file
- "uaccess: unify inline vs outline copy_{from,to}_user() selection"
(Yury Norov)
Simplify the usercopy code by removing the selectability of inlining
copy_{from,to}_user().
- "ocfs2: validate inline xattr header consumers" (ZhengYuan Huang)
Fix a number of possible issues in the ocfs2 xattr code
- "lib and lib/cmdline enhancements" (Dmitry Antipov)
Provide additional robustness checking in the cmdline handling code
and its in-kernel testing and selftests
- "cleanup the RAID6 P/Q library" (Christoph Hellwig)
Clean up the RAID6 P/Q library to match the recent updates to the
RAID 5 XOR library and other CRC/crypto libraries
- "ocfs2: harden inode validators against forged metadata" (Michael
Bommarito)
Add three structural checks to OCFS2 dinode validation so malformed
on-disk fields are rejected before ocfs2_populate_inode() copies them
into the in-core inode
- "lib/raid: replace __get_free_pages() call with kmalloc()" (Mike
Rapoport)
Clean up the lib/raid code by using kmalloc() in more places
* tag 'mm-nonmm-stable-2026-06-21-10-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (108 commits)
ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write
ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits
lib: interval_tree_test: validate benchmark parameters
ocfs2: avoid moving extents to occupied clusters
treewide: fix transposed "sign" typos and update spelling.txt
ocfs2: fix UBSAN array-index-out-of-bounds in ocfs2_sum_rightmost_rec
fat: reject BPB volumes whose data area starts beyond total sectors
selftests/uevent: increase __UEVENT_BUFFER_SIZE to avoid ENOBUFS on busy systems
lib/test_firmware: allocate the configured into_buf size
fs: efs: remove unneeded debug prints
checkpatch: cuppress warnings when Reported-by: is followed by Link:
MAINTAINERS: add Alexander as a kcov reviewer
mailmap: update Alexander Sverdlin's Email addresses
fs: fat: inode: replace sprintf() with scnprintf()
ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent
ocfs2: fix race between ocfs2_control_install_private() and ocfs2_control_release()
ocfs2/dlm: require a ref for locking_state debugfs open
ocfs2: reject FITRIM ranges shorter than a cluster
ocfs2: validate fast symlink target during inode read
ocfs2: add journal NULL check in ocfs2_checkpoint_inode()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- "selftests/mm: clean up build output and verbosity" (Li Wang)
Remove some noise from the MM selftests build
- "mm: Free contiguous order-0 pages efficiently" (Ryan Roberts)
Speed up the freeing of a batch of 0-order pages by first scanning
them for coalescing opportunities. This is applicable to vfree() and
to the releasing of frozen pages
- "mm/damon: introduce DAMOS failed region quota charge ratio"
(SeongJae Park)
Address a DAMOS usability issue: The DAMOS quota often exhausts
prematurely because it charges for all memory attempted, causing slow
and inconsistent performance when actions fail on unreclaimable
memory.
To fix this, a new feature lets users set a smaller, flexible quota
charge ratio (via a numerator and denominator) for failed regions.
Since failed actions cause less overhead, reducing their quota cost
ensures more predictable and efficient DAMOS processing
- "selftests/cgroup: improve zswap tests robustness and support large
page sizes" (Li Wang)
Fix various spurious failures and improves the overall robustness of
the cgroup zswap selftests
- "fix MAP_DROPPABLE not supported errno" (Anthony Yznaga)
Fix an issue in the mlock selftests on arm32
- "mm: huge_memory: clean up defrag sysfs with shared" (Breno Leitao)
Some maintenance work in the huge_memory code
- "treewide: fixup gfp_t printks" (Brendan Jackman)
Use the special vprintf() gfp_t conversion in various places
- "mm: Fix vmemmap optimization accounting and initialization" (Muchun
Song)
Fix several bugs in the vmemmap optimization, mainly around incorrect
page accounting and memmap initialization in the DAX and memory
hotplug paths. It also fixes pageblock migratetype initialization and
struct page initialization for ZONE_DEVICE compound pages
- "mm/damon: repost non-hotfix reviewed patches in damon/next tree"
A sprinkle of unrelated minor bugfixes for DAMON
- "mm: remove page_mapped()" (David Hildenbrand)
Remove this function from the tree, replacing it with folio_mapped()
- "mm/damon: let DAMON be paused and resumed" (SeongJae Park)
Allow DAMON to be paused and resumed without losing its current state
- "kasan: hw_tags: Disable tagging for stack and page-tables" (Muhammad
Usama Anjum)
Simplify and speed up kasan by removing its ineffective tagging of
stacks and page tables
- "mm/damon/reclaim,lru_sort: monitor all system rams by default"
(SeongJae Park)
Simplify deployment on diverse hardware like NUMA systems by updating
DAMON_RECLAIM and DAMON_LRU_SORT to automatically monitor the
physical address range covering all System RAM areas by default,
replacing the overly restrictive behavior that only targeted the
single largest memory block to save on negligible overhead
- "mm/damon/sysfs: document filters/ directory as deprecated" (SeongJae
Park)
Update some DAMON docs
- "mm: use spinlock guards for zone lock" (Dmitry Ilvokhin)
Switch zone->lock handling over to using the guard() mechanisms
- "mm/filemap: tighten mmap_miss hit accounting" (fujunjie)
Fix a flaw where the mmap_miss counter over-credited page cache hits
during fault-arounds and page-fault retries. This results in
significant reduction of redundant synchronous mmap readahead I/O,
drastically cutting down execution time and gigabytes read for sparse
random or strided memory access workloads
- "selftests/cgroup: Fix false positive failures in test_percpu_basic"
(Li Wang)
Fix a couple of false-positives in the cgroup kmem selftests
- "mm/damon/reclaim: support monitoring intervals auto-tuning"
(SeongJae Park)
Add a new parameter to DAMON permitting DAMON_RECLAIM to
automatically tune DAMON's sampling and aggregation intervals
- "mm/damon/stat: add kdamond_pid parameter" (SeongJae Park)
Change DAMON_STAT to provide the pid of its kdamond
- "mm/kmemleak: dedupe verbose scan output" (Breno Leitao)
Remove large amounts of duplicated backtraces from the verbose-mode
kmemleak output
- "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 1)" (David
Hildenbrand)
Reduce our use of CONFIG_HAVE_BOOTMEM_INFO_NODE, with a view to
removing it entirely in a later series
- "mm/damon: validate min_region_size to be power of 2" (Liew Rui Yan)
Prevent users from passing a non-power-of-2 value of `addr_unit', as
this later results in undesirable behavior
- "mm: document read_pages and simplify usage" (Frederick Mayle)
- "tools/mm/page-types: Fix misc bugs" (Ye Liu)
Fix three issues in tools/mm/page-types.c
- "mm: misc cleanups from __GFP_UNMAPPED series" (Brendan Jackman)
Implement several cleanups in the page allocator and related code
- "mm, swap: swap table phase IV: unify allocation" (Kairui Song)
Unify the allocation and charging of anon and shmem swap in folios,
provides better synchronization, consolidates the metadata
management, hence dropping the static array and map, and improves
performance
- "mm/damon: introduce data attributes monitoring" (SeongJae Park(
Extend DAMON to monitor general data attributes other than accesses
- "mm/vmalloc: free unused pages on vrealloc() shrink" (Shivam Kalra)
Implement the TODO in vrealloc() to unmap and free unused pages when
shrinking across a page boundary
- "mm/damon: documentation and comment fixes" (niecheng)
- "remove mmap_action success, error hooks" (Lorenzo Stoakes)
Eliminate custom hooks from mmap_action by removing the problematic
success_hook which allowed drivers to improperly access uninitialized
VMAs. It replaces the error_hook with a simple error-code field and
updates the memory char driver accordingly
- "mm/damon: minor improvements for code readability and tests"
(SeongJae Park)
- "mm/damon: fix macro arguments and clarify quota goals doc" (Maksym
Shcherba)
- "userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c" (Mike
Rapoport)
- "mm/mglru: improve reclaim loop and dirty folio" (Kairui Song and
others)
Clean up and slightly improves MGLRU's reclaim loop and dirty
writeback handling. Large performance improvements are measured
- "use vma locks for proc/pid/{smaps|numa_maps} reads" (Suren
Baghdasaryan)
Use per-vma locks when reading /proc/pid/smaps and numa_maps similar
to reduce contention on central mmap_lock
- "refactors thpsize_shmem_enabled_store() and thpsize_shmem_enabled_show()"
(Ran Xiaokai)
Some cleanup work in the THP code
- "selftests/memfd: fix compilation warnings" (Konstantin Khorenko)
Fix a few build glitches in the memfd selftest code.
- "memcg: shrink obj_stock_pcp and cache multiple objcgs" (Shakeel
Butt)
Resolve a 68% performance regression caused by NUMA-node cache
thrashing around struct obj_stock_pcp by shrinking its existing
fields and expanding it into a multi-slot array that caches up to
five obj_cgroup pointers per CPU, allowing per-node variants of the
same memcg to coexist within a single 64-byte cache line.
- "zram: writeback fixes" (Sergey Senozhatsky)
address a couple of unrelated zram writeback issues
- "mm: switch THP shrinker to list_lru" (Johannes Weiner)
Resolve NUMA-awareness issues and streamlines callsite interaction by
refactoring and extending the list_lru API to completely replace the
complex, open-coded deferred split queue for Transparent Huge Pages
- "mm: improve large folio readahead for exec memory" (Usama Arif)
Improve large-folio readahead on systems like 64K-page arm64 by
preventing the mmap_miss check from permanently disabling
target-oriented VM_EXEC readahead, and by generalizing the
force_thp_readahead gate to support mappings with any usefully large
maximum folio order under the cache cap.
- "userfaultfd/pagemap: pre-existing fixes" (Kiryl Shutsemau)
Fix a bunch of minor issues in the userfaultfd/pagemap, all of which
were flagged by Sashiko review of proposed new material
- "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and
vmemmap_check_pmd()" (Muchun Song)
Provide generic versions of these two functions so the four
arch-specific implementations can be removed.
- "mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap
device" (Youngjun Park)
Address a uswsusp-vs-swapoff race and reduces the swap device
reference taking/releasing frequency.
- "mm/hmm: A fix and a selftest" (Dev Jain)
* tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
selftests/mm/hmm-tests: test pagemap reads of PMD device-private entries
fs/proc/task_mmu: do not warn on seeing non-migration pmd entry
lib/test_hmm: check alloc_page_vma() return value and handle OOM
mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX
mm/swap: remove redundant swap device reference in alloc/free
mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device
mm/filemap: use folio_next_index() for start
vmalloc: fix NULL pointer dereference in is_vm_area_hugepages()
sparc/mm: drop vmemmap_check_pmd helper and use generic code
loongarch/mm: drop vmemmap_check_pmd helper and use generic code
riscv/mm: drop vmemmap_pmd helpers and use generic code
arm64/mm: drop vmemmap_pmd helpers and use generic code
mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()
rust: page: mark Page::nid as inline
userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks
userfaultfd: gate must_wait writability check on pte_present()
mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade
fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()
fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry()
fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race
...
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gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip
Pull NOHZ updates from Thomas Gleixner:
- Fix a long standing TOCTOU in get_cpu_sleep_time_us()
- Make the CPU offline NOHZ handling more robust by disabling NOHZ on
the outgoing CPU early instead of creating unneeded state which needs
to be undone.
- Unify idle CPU time accounting instead of having two different
accounting mechanisms. These two different mechanisms are not really
independent, but the different properties can in the worst case cause
that gloabl idle time can be observed going backwards.
- Consolidate the idle/iowait time retrieval interfaces instead of
converting back and forth between them.
- Make idle interrupt time accounting more robust. The original code
assumes that interrupt time accouting is enabled and therefore stops
elapsing idle time while an interrupt is handled in NOHZ dyntick
state. That assumption is not correct as interrupt time accounting
can be disabled at compile and runtime.
- Fix an accounting error between dyntick idle time and dyntick idle
steal time. The stolen time is not accounted and therefore idle time
becomes inaccurate. The stolen time is now accounted after the fact
as there is no way to predict the steal time upfront.
* tag 'timers-nohz-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
sched/cputime: Handle dyntick-idle steal time correctly
sched/cputime: Handle idle irqtime gracefully
sched/cputime: Provide get_cpu_[idle|iowait]_time_us() off-case
tick/sched: Consolidate idle time fetching APIs
tick/sched: Account tickless idle cputime only when tick is stopped
tick/sched: Remove unused fields
tick/sched: Move dyntick-idle cputime accounting to cputime code
tick/sched: Remove nohz disabled special case in cputime fetch
tick/sched: Unify idle cputime accounting
s390/time: Prepare to stop elapsing in dynticks-idle
powerpc/time: Prepare to stop elapsing in dynticks-idle
sched/cputime: Correctly support generic vtime idle time
sched/cputime: Remove superfluous and error prone kcpustat_field() parameter
sched/idle: Handle offlining first in idle loop
tick/sched: Fix TOCTOU in nohz idle time fetch
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gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip
Pull interrupt core updates from Thomas Gleixner:
- Rework of /proc/interrupt handling:
/proc/interrupts was subject to micro optimizations for a long time,
but most of the low hanging fruit was left on the table. This rework
addresses the major time consuming issues:
- Printing a long series of zeros one by one via a format string
instead of counting subsequent zeros and emitting a string
constant.
- Simplify and cache the conditions whether interrupts should be
printed
- Use a proper iteration over the interrupt descriptor xarray
instead of walking and testing one by one.
- Provide helper functions for the architecture code to emit the
architecture specific counters
- Convert the counter structure in x86 to an array, which
simplifies the output and add mechanisms to suppress unused
architecture interrupts, which just occupy space for nothing.
Adopt the new core mechanisms.
This adjusts the gdb scripts related to interrupt counter statistics
to work with the new mechanisms.
- Prevent a string overflow in the /proc/irq/$N/ directory name
creation code.
* tag 'irq-core-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
x86/irq: Add missing 's' back to thermal event printout
genirq/proc: Speed up /proc/interrupts iteration
genirq/proc: Runtime size the chip name
genirq: Expose irq_find_desc_at_or_after() in core code
genirq: Add rcuref count to struct irq_desc
genirq/proc: Increase default interrupt number precision to four
genirq: Calculate precision only when required
genirq: Cache the condition for /proc/interrupts exposure
genirq/manage: Make NMI cleanup RT safe
genirq: Expose nr_irqs in core code
scripts/gdb: Update x86 interrupts to the array based storage
x86/irq: Move IOAPIC misrouted and PIC/APIC error counts into irq_stats
x86/irq: Suppress unlikely interrupt stats by default
x86/irq: Make irqstats array based
genirq/proc: Utilize irq_desc::tot_count to avoid evaluation
genirq/proc: Avoid formatting zero counts in /proc/interrupts
x86/irq: Optimize interrupts decimals printing
genirq/proc: Size interrupt directory names for 10-digit interrupt numbers
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull dcache updates from Al Viro:
- d_alloc_parallel() API change (Neil's with my changes)
- NORCU fixes
- Reorganization and simplification of dentry eviction logic
- Simplifying rcu_read_lock() scopes in fs/dcache.c
- Secondary roots work - getting rid of NFS fake root dentries and
dealing with remaining shrink_dcache_for_umount() and
shrink_dentry_list() races
- making cursors NORCU (surprisingly easy)
* tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (22 commits)
make cursors NORCU
nfs: get rid of fake root dentries
wind ->s_roots via ->d_sib instead of ->d_hash
shrink_dentry_tree(): unify the calls of shrink_dentry_list()
shrinking rcu_read_lock() scope in d_alloc_parallel()
d_walk(): shrink rcu_read_lock() scope
document dentry_kill()
adjust calling conventions of lock_for_kill(), fold __dentry_kill() into dentry_kill()
Document rcu_read_lock() use in select_collect2()
Shift rcu_read_{,un}lock() inside fast_dput()
simplify safety for lock_for_kill() slowpath
fold lock_for_kill() and __dentry_kill() into common helper
fold lock_for_kill() into shrink_kill()
shrink_dentry_list(): start with removing from shrink list
d_prune_aliases(): make sure to skip NORCU aliases
kill d_dispose_if_unused()
make to_shrink_list() return whether it has moved dentry to list
select_collect(): ignore dentries on shrink lists if they have positive refcounts
find_acceptable_alias(): skip NORCU aliases with zero refcount
fix a race between d_find_any_alias() and final dput() of NORCU dentries
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull procfs updates from Christian Brauner:
- Revamp fs/filesystems.c
The file was a mess with a hand-rolled linked list in desperate need
of a cleanup. The filesystems list is now RCU-ified, /proc files can
be marked permanent from outside fs/proc/, and the string emitted
when reading /proc/filesystems is pre-generated and cached instead of
pointer-chasing and printfing entry by entry on every read.
The file is read frequently because libselinux reads it and is linked
into numerous frequently used programs (even ones you would not
suspect, like sed!). Scalability also improves since reference
maintenance on open/close is bypassed.
open+read+close cycle single-threaded (ops/s):
before: 442732
after: 1063462 (+140%)
open+read+close cycle with 20 processes (ops/s):
before: 606177
after: 3300576 (+444%)
A follow-up patch adds missing unlocks in some corner cases and
tidies things up.
- Relax the mount visibility check for subset=pid mounts
When procfs is mounted with subset=pid, all static files become
unavailable and only the dynamic pid information is accessible. In
that case there is no point in imposing the full mount visibility
restrictions on the mounter - everything that can be hidden in procfs
is already inaccessible. These restrictions prevented procfs from
being mounted inside rootless containers since almost all container
implementations overmount parts of procfs to hide certain
directories.
As part of this /proc/self/net is only shown in subset=pid mounts for
CAP_NET_ADMIN, reconfiguring subset=pid is rejected, the
SB_I_USERNS_VISIBLE superblock flag is replaced with an
FS_USERNS_MOUNT_RESTRICTED filesystem flag, fully visible mounts are
recorded in a list, and the mount restrictions are finally
documented.
- Protect ptrace_may_access() with exec_update_lock in procfs
Most uses of ptrace_may_access() in procfs should hold
exec_update_lock to avoid TOCTOU issues with concurrent privileged
execve() (like setuid binary execution).
This fixes the easy cases - the owner and visibility checks and the
FD link permission checks - with the gnarlier ones to follow later.
* tag 'vfs-7.2-rc1.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: fix ups and tidy ups to /proc/filesystems caching
proc: protect ptrace_may_access() with exec_update_lock (FD links)
proc: protect ptrace_may_access() with exec_update_lock (part 1)
docs: proc: add documentation about mount restrictions
proc: handle subset=pid separately in userns visibility checks
proc: prevent reconfiguring subset=pid
proc: subset=pid: Show /proc/self/net only for CAP_NET_ADMIN
fs: cache the string generated by reading /proc/filesystems
sysfs: remove trivial sysfs_get_tree() wrapper
fs: RCU-ify filesystems list
fs: move SB_I_USERNS_VISIBLE to FS_USERNS_MOUNT_RESTRICTED
proc: allow to mark /proc files permanent outside of fs/proc/
namespace: record fully visible mounts in list
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
"Features:
- Reduce pipe->mutex contention by pre-allocating pages outside the
lock in anon_pipe_write().
anon_pipe_write() called alloc_page() once per page while holding
pipe->mutex. The allocation can sleep doing direct reclaim and runs
memcg charging, which extends the critical section and stalls any
concurrent reader on the same mutex. Now up to 8 pages are
pre-allocated before the mutex is taken, leftovers are recycled
into the per-pipe tmp_page[] cache before unlock, and any remainder
is released after unlock, keeping the allocator out of the critical
section on both sides. On a writers x readers sweep with 64KB
writes against a 1 MB pipe throughput improves 6-28% and average
write latency drops 5-22%; under memory pressure - when the cost of
holding the mutex across reclaim is highest - throughput improves
21-48% and latency drops 17-33%. The microbenchmark is added to
selftests.
- uaccess/sockptr: fix the ignored_trailing logic in
copy_struct_to_user() to behave as documented and the usize check
in copy_struct_from_sockptr() for user pointers, and add
copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr()
helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC).
- bpf: add a sleepable bpf_real_inode() kfunc that resolves the real
inode backing a dentry via d_real_inode(). On overlayfs the inode
attached to the dentry doesn't carry the underlying device
information; this is used by the filesystem restriction BPF program
that was merged into systemd.
- docs: add guidelines for submitting new filesystems, motivated by
the maintenance burden abandoned and untestable filesystems impose
on VFS developers, blocking infrastructure work like folio
conversions and iomap migration.
Fixes:
- libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
and drop the now-redundant assignments in callers. This began as a
one-line dma-buf fix for a path_noexec() warning; a pseudo
filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo()
callers were audited: the only visible effect is on dma-buf where
SB_I_NOEXEC silences the warning.
- Handle set_blocksize() failures in legacy filesystems (bfs, hpfs,
qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a
device with a sector size > PAGE_SIZE crashed roughly half of them;
the rest had the same missing error handling pattern. Plus a
follow-up releasing the superblock buffer_head when setting the
minix v3 block size fails.
- mount: honour SB_NOUSER in the new mount API.
- fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by
switching the process-group paths of send_sigio() and send_sigurg()
from read_lock(&tasklist_lock) to RCU, matching the single-PID
path.
- vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing
delegated NFS mounts (fsopen() in a container with the mount
performed by a privileged daemon) that broke when non-init
s_user_ns was tied to FS_USERNS_MOUNT.
- selftests/namespaces: fix a hang in nsid_test where an unreaped
grandchild kept the TAP pipe write-end open, a waitpid(-1) race in
listns_efault_test, and a false FAIL on kernels without listns()
where the tests should SKIP.
- filelock: fix the break_lease() stub signature for
CONFIG_FILE_LOCKING=n.
- init/initramfs_test: wait for the async initramfs unpacking before
running; the test and do_populate_rootfs() share the parser state.
- fs/coredump: reduce redundant log noise in
validate_coredump_safety().
- iomap: pass the correct length to fserror_report_io() in
__iomap_write_begin().
- backing-file: fix the backing_file_open() kerneldoc.
Cleanups:
- initramfs: refactor the cpio hex header parsing to use hex2bin()
instead of the hand-rolled simple_strntoul() which is reverted, and
extend the initramfs KUnit tests to cover header fields with 0x
prefixes.
- Replace __get_free_pages() and friends with kmalloc()/kzalloc()
across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2,
isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the
do_mounts init code - part of the larger work of replacing page
allocator calls with kmalloc().
- Use clear_and_wake_up_bit() in unlock_buffer() and
journal_end_buffer_io_sync() instead of open-coding the sequence.
- Drop unused VFS exports: unexport drop_super_exclusive(), remove
start_removing_user_path_at(), and fold __start_removing_path()
into start_removing_path().
- fs/read_write: narrow the __kernel_write() export with
EXPORT_SYMBOL_FOR_MODULES().
- vfs: uapi: retire octal and hex constants in favor of (1 << n) for
the O_ flags. Finding a free bit for a new flag across the
architectures was needlessly hard with the mixed bases.
- dcache: add extra sanity checks of dead dentries in dentry_free()
via a new DENTRY_WARN_ONCE() that also prints d_flags.
- iov_iter: use kmemdup_array() in dup_iter() to harden the
allocation against multiplication overflow.
- fs/pipe: write to ->poll_usage only once.
- vfs: remove an always-taken if-branch in find_next_fd().
- dcache: use kmalloc_flex() for struct external_name in __d_alloc().
- namei: use QSTR() instead of QSTR_INIT() in path_pts().
- sync_file_range: delete dead S_ISLNK code.
- Comment fixes: retire a stale comment in fget_task_next() and fix
assorted spelling mistakes"
* tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits)
backing-file: fix backing_file_open() kerneldoc parameter
iomap: pass the correct len to fserror_report_io in __iomap_write_begin
vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS
filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n
vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags
bpf: add bpf_real_inode() kfunc
fs/read_write: Do not export __kernel_write() to the entire world
libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers
libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
mount: honour SB_NOUSER in the new mount API
fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling
selftests/pipe: add pipe_bench microbenchmark
fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write
fs: retire stale comment in fget_task_next()
fs: fix spelling mistakes in comment
bfs: replace get_zeroed_page() with kzalloc()
binfmt_misc: replace __get_free_page() with kmalloc()
configfs: replace __get_free_pages() with kzalloc()
fs/namespace: use __getname() to allocate mntpath buffer
fs/select: replace __get_free_page() with kmalloc()
...
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Patch series "mm/hmm: A fix and a selftest", v3.
Patch 1 fixes a stale warning present from the time when only migration
softleaf entries were supported at the PMD level.
Patch 2 adds some code into hmm-tests.c which exercises the pagemap path
for PMD device-private entries.
This patch (of 2):
pagemap_pmd_range_thp() warns if a non-present PMD is not a migration
entry. This became false once device-private entries at the PMD level
were added.
Therefore, remove the stale migration-only assertion.
Link: https://lore.kernel.org/20260604055308.1947679-1-dev.jain@arm.com
Link: https://lore.kernel.org/20260604055308.1947679-2-dev.jain@arm.com
Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages")
Signed-off-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Tested-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Oscar Salvador (SUSE) <osalvador@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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A PAGEMAP_SCAN ioctl requesting PM_SCAN_WP_MATCHING on a hugetlb VMA hangs
the calling thread, unkillably, as soon as the scan reaches an unpopulated
part of the range:
do_pagemap_scan()
walk_page_range()
walk_hugetlb_range()
hugetlb_vma_lock_read() # take the vma lock for read ...
pagemap_scan_pte_hole() # ... ->pte_hole() for a hole
uffd_wp_range()
change_protection()
hugetlb_change_protection()
hugetlb_vma_lock_write() # ... and block taking it for write
walk_hugetlb_range() holds the hugetlb vma lock for read across the whole
walk. A present entry goes to ->hugetlb_entry(); an unpopulated one goes
to ->pte_hole(), i.e. pagemap_scan_pte_hole(). To write-protect the hole
that handler calls uffd_wp_range(), which on a hugetlb VMA reaches
hugetlb_change_protection() and takes the same vma lock for write. The
thread then blocks in down_write() waiting for the read lock it is itself
holding.
The populated path avoids this: pagemap_scan_hugetlb_entry()
write-protects the entry inline under the page-table lock and never enters
hugetlb_change_protection().
Do the same for holes. Fault in the page table and install the uffd-wp
marker directly with make_uffd_wp_huge_pte() under the page-table lock,
rather than routing through uffd_wp_range(). That is the same sequence
hugetlb_change_protection() runs for an unpopulated entry, minus the vma
write lock -- which is safe to skip because PMD sharing is disabled on
uffd-wp VMAs (hugetlb_unshare_all_pmds() runs at registration), leaving
nothing for that lock to serialise against.
Link: https://lore.kernel.org/20260529172331.356655-4-kas@kernel.org
Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Reported-by: Sashiko AI review <sashiko-bot@kernel.org>
Assisted-by: Claude:claude-opus-4-8
Cc: David Hildenbrand <david@kernel.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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The partial-page check compares against HPAGE_SIZE (PMD_SIZE), which is
wrong for gigantic hugetlb hstates (e.g. 1G). The walker hands the
callback a huge_page_size()-sized range, never start + HPAGE_SIZE, so the
comparison always declares it partial and aborts the WP. Compare against
the actual hstate's page size.
Link: https://lore.kernel.org/20260529172331.356655-3-kas@kernel.org
Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Reported-by: Sashiko AI review <sashiko-bot@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "userfaultfd/pagemap: pre-existing fixes".
These are pre-existing bug fixes that were carried at the front of the
userfaultfd RWP working-set-tracking series up to v5 [1]. Per review
feedback that fixes should not sit in the middle of a feature series, they
are split out and sent on their own; the RWP series is reposted rebased on
top of this.
All six were flagged by the Sashiko AI review of the RWP series and carry
Reported-by: Sashiko AI review <sashiko-bot@kernel.org>. They are
independent of RWP, apply to mm-new directly, and carry Cc: stable@.
1: fs/proc/task_mmu: a missing huge_ptep_modify_prot_start() in
make_uffd_wp_huge_pte() can lose hardware Dirty/Accessed updates
when PAGEMAP_SCAN write-protects a hugetlb PTE.
2: fs/proc/task_mmu: pagemap_scan_hugetlb_entry() compares the range
against HPAGE_SIZE rather than the hstate page size, so it never
write-protects gigantic hugetlb pages.
3: fs/proc/task_mmu: PAGEMAP_SCAN with PM_SCAN_WP_MATCHING over an
unpopulated hugetlb range self-deadlocks -- pagemap_scan_pte_hole()
calls uffd_wp_range() while walk_hugetlb_range() holds the hugetlb
vma lock for read, and hugetlb_change_protection() then takes it
for write. Install the marker inline instead.
4: mm/huge_memory: change_non_present_huge_pmd() drops pmd_swp_uffd_wp
on a device-private PMD permission downgrade, silently losing the
uffd-wp marker.
5: userfaultfd: must_wait() applies pte_write() to a locklessly read
PTE without checking pte_present(), so swap/migration entries
decode random offset bits and a thread can stay parked on a stale
fault.
6: userfaultfd: __VMA_UFFD_FLAGS feeds VMA_UFFD_MINOR_BIT (41) to
mk_vma_flags() unconditionally, an out-of-bounds write into the
single-word vma_flags_t on 32-bit. Build the mask from config-gated
per-mode masks so an unavailable bit is never materialised.
This patch (of 6):
make_uffd_wp_huge_pte() arms the UFFD_WP bit on a present HugeTLB PTE by
calling huge_ptep_modify_prot_commit() with a ptent snapshot that was
fetched without the corresponding huge_ptep_modify_prot_start(). The
start helper is what atomically clears the entry so the kernel-owned
snapshot stays consistent until the commit; without it, the hardware may
set Dirty or Accessed in the live PTE between the original read and the
commit, and huge_ptep_modify_prot_commit() (whose generic implementation
just calls set_huge_pte_at()) then writes the stale snapshot back over the
live hardware bits, losing the update.
The non-hugetlb sibling make_uffd_wp_pte() does this correctly via
ptep_modify_prot_start() / ptep_modify_prot_commit(). Mirror that pattern
for the present-PTE branch. The migration case stays as-is -- migration
entries are non-present, so there's no hardware update to race against.
Link: https://lore.kernel.org/20260529172331.356655-1-kas@kernel.org
Link: https://lore.kernel.org/20260529172331.356655-2-kas@kernel.org
Link: https://lore.kernel.org/all/20260526130509.2748441-1-kirill@shutemov.name/ [1]
Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Reported-by: Sashiko AI review <sashiko-bot@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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proc_pid_get_link() and proc_pid_readlink() currently look up the task from
the pid once, then do the ptrace access check on that task, then look up
the task from the pid a second time to do the actual access.
That's racy in several ways.
To fix it, pass the task to the ->proc_get_link() handler, and instead of
proc_fd_access_allowed(), introduce a new helper call_proc_get_link() that
looks up and locks the task, does the access check, and calls
->proc_get_link().
Fixes: 778c1144771f ("[PATCH] proc: Use sane permission checks on the /proc/<pid>/fd/ symlinks")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://patch.msgid.link/20260518-procfs-lockfix-part1-v1-2-5c3d20e0ac33@google.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Fix the easy cases where procfs currently calls ptrace_may_access() without
exec_update_lock protection, where the fix is to simply add the extra lock
or use mm_access():
- do_task_stat(): grab exec_update_lock
- proc_pid_wchan(): grab exec_update_lock
- proc_map_files_lookup(): use mm_access() instead of get_task_mm()
- proc_map_files_readdir(): use mm_access() instead of get_task_mm()
- proc_ns_get_link(): grab exec_update_lock
- proc_ns_readlink(): grab exec_update_lock
Fixes: f83ce3e6b02d ("proc: avoid information leaks to non-privileged processes")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://patch.msgid.link/20260518-procfs-lockfix-part1-v1-1-5c3d20e0ac33@google.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Parallel lookup starts with a call of d_alloc_parallel(). That primitive
either returns a matching hashed dentry or allocates a new one in the
in-lookup state and returns it to the caller. Once the caller is done
with lookup, it indicates so either by call of d_{splice_alias,add}()
or by call of d_done_lookup(); at that point dentry leaves the in-lookup
state.
If d_alloc_parallel() finds a matching in-lookup dentry, it must wait for
that dentry to leave the in-lookup state, on |
