kernel/git/next/linux-next.git/fs/proc, branch master

Merge branch 'fs-next' of linux-next

2026-07-10T12:00:04+00:00

Merge branch 'vfs.all' of https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git

2026-07-10T10:32:58+00:00

# Conflicts: # fs/bpf_fs_kfuncs.c # tools/testing/selftests/filesystems/.gitignore # tools/testing/selftests/filesystems/Makefile

mm/pagemap: add PAGE_IS_ACCESSED for RWP tracking

2026-07-10T03:15:42+00:00

PAGEMAP_SCAN already reports PAGE_IS_WRITTEN from the inverted uffd PTE bit, targeting the UFFDIO_WRITEPROTECT workflow. UFFDIO_RWPROTECT reuses the same PTE bit as a marker for read-write protection, but "has been written" and "has been accessed" are distinct semantic signals — they happen to share one PTE bit today only because the two implementations share infrastructure. Give RWP its own pagemap category so the UAPI does not conflate them: PAGE_IS_WRITTEN reported on VM_UFFD_WP VMAs, !pte_uffd(pte) PAGE_IS_ACCESSED reported on VM_UFFD_RWP VMAs, !pte_uffd(pte) Both still read the same PTE bit today, but each is scoped to the VMA whose registered mode makes the bit meaningful. If a future implementation moves RWP to a separate PTE bit, only PAGE_IS_ACCESSED switches over. This is a UAPI narrowing. Outside VM_UFFD_WP VMAs the uffd bit is always clear, so PAGEMAP_SCAN used to flag PAGE_IS_WRITTEN on every present PTE there — a meaningless duplicate of PAGE_IS_PRESENT. Now PAGE_IS_WRITTEN fires only inside VM_UFFD_WP VMAs. pagemap_hugetlb_category() now takes the vma like its PTE/PMD peers. Link: https://lore.kernel.org/20260708111417.173443-12-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau Assisted-by: Claude:claude-opus-4-6 Acked-by: Mike Rapoport (Microsoft) Cc: Andrea Arcangeli Cc: David Hildenbrand Cc: James Houghton Cc: Jonathan Corbet Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Paolo Bonzini Cc: Peter Xu Cc: Sean Christopherson Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton

mm: add VM_UFFD_RWP VMA flag

2026-07-10T03:15:40+00:00

Preparatory patch for userfaultfd read-write protection (RWP). RWP extends userfaultfd protection from plain write-protection (WP) to full read-write protection: accesses to an RWP-protected range -- reads as well as writes -- trap through userfaultfd. Reserve VM_UFFD_RWP, add the userfaultfd_rwp() and userfaultfd_protected() helpers, and wire up the smaps "ur" entry and the trace-flag table the rest of the series will use. The flag is gated on CONFIG_USERFAULTFD_RWP, which is introduced together with the UAPI in a later patch; until then VM_UFFD_RWP aliases VM_NONE and every downstream check folds to dead code. Nothing sets or queries the flag yet. Link: https://lore.kernel.org/20260708111417.173443-6-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau Assisted-by: Claude:claude-opus-4-6 Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: SeongJae Park Reviewed-by: Lorenzo Stoakes Cc: Andrea Arcangeli Cc: David Hildenbrand Cc: James Houghton Cc: Jonathan Corbet Cc: Liam Howlett Cc: Paolo Bonzini Cc: Peter Xu Cc: Sean Christopherson Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton

mm: rename uffd-wp PTE accessors to uffd

2026-07-10T03:15:40+00:00

Userfaultfd RWP will reuse the uffd-wp PTE bit to mark access-tracking PTEs, alongside the write-protected ones it already marks. The bit's meaning now depends on the VMA flag (WP or RWP), not on its name. Rename the kernel-internal names that describe the bit: - pte/pmd/huge_pte accessors (and swap variants) - pgtable_supports_uffd() capability query - SCAN_PTE_UFFD khugepaged enum The ftrace string emitted by mm_khugepaged_scan_pmd for this enum is kept as "pte_uffd_wp" so existing trace-based tooling keeps matching. Pure mechanical rename -- no behavior change. Link: https://lore.kernel.org/20260708111417.173443-4-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau Assisted-by: Claude:claude-opus-4-6 Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: SeongJae Park Cc: Andrea Arcangeli Cc: David Hildenbrand Cc: James Houghton Cc: Jonathan Corbet Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Paolo Bonzini Cc: Peter Xu Cc: Sean Christopherson Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton

fs/proc: use softleaf_has_pfn() in pagemap PMD walker

2026-07-10T03:14:57+00:00

pagemap_pmd_range_thp() assumes that every non-present PMD is a migration entry and unconditionally calls softleaf_to_page(). This will crash on any non-present PMD type that does not encode a PFN, such as the upcoming PMD-level swap entries. Guard the page lookup with softleaf_has_pfn(), matching how pte_to_pagemap_entry() already handles non-present PTEs. Link: https://lore.kernel.org/20260706114320.1643046-4-usama.arif@linux.dev Signed-off-by: Usama Arif Acked-by: David Hildenbrand (Arm) Reviewed-by: Zi Yan Cc: Alexandre Ghiti Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Chris Li Cc: Dev Jain Cc: "Huang, Ying" Cc: Johannes Weiner Cc: Kairui Song Cc: Kemeng Shi Cc: Kiryl Shutsemau Cc: Lance Yang Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Nhat Pham Cc: Nico Pache Cc: Rik van Riel Cc: Ryan Roberts Cc: Shakeel Butt Cc: Vlastimil Babka Signed-off-by: Andrew Morton

fs/proc/task_mmu: fix PAGEMAP_SCAN written state for PMD holes

2026-07-10T03:13:38+00:00

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. MADV_DONTNEED has fill-with-zeros semantics: it changes the contents of the range to zeroes (a subsequent read maps the zero page), which write tracking must report as written. 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 -- and the zeroing goes unreported. A write-tracking checkpoint/migration tool (e.g. CRIU) then treats the range as unchanged and keeps its previous contents, so 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. Add a pagemap_ioctl selftest covering the anon-THP PMD-hole case. Link: https://lore.kernel.org/20260709121629.205562-1-kirill@shutemov.name Fixes: 2bad466cc9d9 ("mm/uffd: UFFD_FEATURE_WP_UNPOPULATED") Signed-off-by: Kiryl Shutsemau Reported-by: Sashiko AI review Closes: https://sashiko.dev/#/patchset/20260707151349.92143-1-kirill@shutemov.name Cc: Muhammad Usama Anjum Cc: Peter Xu Assisted-by: Claude:claude-fable-5 Cc: David Hildenbrand Cc: Jann Horn Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Pedro Falcato Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton

fs/proc/task_mmu: fix PAGEMAP_SCAN written state for unpopulated ptes

2026-07-10T03:13:36+00:00

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 Cc: Muhammad Usama Anjum Cc: David Hildenbrand Cc: Jann Horn Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Pedro Falcato Cc: Peter Xu Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Assisted-by: Claude:claude-fable-5 Cc: Signed-off-by: Andrew Morton

Merge tag 'mm-hotfixes-stable-2026-07-06-17-49' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-07-07T01:51:36+00:00

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

fs/proc: fix KPF_KSM reported for all anonymous pages

2026-07-02T02:02:54+00:00

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 Acked-by: David Hildenbrand (Arm) Acked-by: Zi Yan Reviewed-by: Xu Xin Cc: Chengming Zhou Cc: Kefeng Wang Cc: Luiz Capitulino Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Nanyong Sun Cc: Svetly Todorov Cc: Signed-off-by: Andrew Morton