August 2025 - Linux-stable-mirror

[merged mm-hotfixes-stable] mm-mremap-fix-warn-with-uffd-that-has-remap-events-disabled.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/mremap: fix WARN with uffd that has remap events disabled has been removed from the -mm tree. Its filename was mm-mremap-fix-warn-with-uffd-that-has-remap-events-disabled.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: David Hildenbrand <david(a)redhat.com> Subject: mm/mremap: fix WARN with uffd that has remap events disabled Date: Mon, 18 Aug 2025 19:53:58 +0200 Registering userfaultd on a VMA that spans at least one PMD and then mremap()'ing that VMA can trigger a WARN when recovering from a failed page table move due to a page table allocation error. The code ends up doing the right thing (recurse, avoiding moving actual page tables), but triggering that WARN is unpleasant: WARNING: CPU: 2 PID: 6133 at mm/mremap.c:357 move_normal_pmd mm/mremap.c:357 [inline] WARNING: CPU: 2 PID: 6133 at mm/mremap.c:357 move_pgt_entry mm/mremap.c:595 [inline] WARNING: CPU: 2 PID: 6133 at mm/mremap.c:357 move_page_tables+0x3832/0x44a0 mm/mremap.c:852 Modules linked in: CPU: 2 UID: 0 PID: 6133 Comm: syz.0.19 Not tainted 6.17.0-rc1-syzkaller-00004-g53e760d89498 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:move_normal_pmd mm/mremap.c:357 [inline] RIP: 0010:move_pgt_entry mm/mremap.c:595 [inline] RIP: 0010:move_page_tables+0x3832/0x44a0 mm/mremap.c:852 Code: ... RSP: 0018:ffffc900037a76d8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 0000000032930007 RCX: ffffffff820c6645 RDX: ffff88802e56a440 RSI: ffffffff820c7201 RDI: 0000000000000007 RBP: ffff888037728fc0 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000032930007 R11: 0000000000000000 R12: 0000000000000000 R13: ffffc900037a79a8 R14: 0000000000000001 R15: dffffc0000000000 FS: 000055556316a500(0000) GS:ffff8880d68bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30863fff CR3: 0000000050171000 CR4: 0000000000352ef0 Call Trace: <TASK> copy_vma_and_data+0x468/0x790 mm/mremap.c:1215 move_vma+0x548/0x1780 mm/mremap.c:1282 mremap_to+0x1b7/0x450 mm/mremap.c:1406 do_mremap+0xfad/0x1f80 mm/mremap.c:1921 __do_sys_mremap+0x119/0x170 mm/mremap.c:1977 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f00d0b8ebe9 Code: ... RSP: 002b:00007ffe5ea5ee98 EFLAGS: 00000246 ORIG_RAX: 0000000000000019 RAX: ffffffffffffffda RBX: 00007f00d0db5fa0 RCX: 00007f00d0b8ebe9 RDX: 0000000000400000 RSI: 0000000000c00000 RDI: 0000200000000000 RBP: 00007ffe5ea5eef0 R08: 0000200000c00000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000002 R13: 00007f00d0db5fa0 R14: 00007f00d0db5fa0 R15: 0000000000000005 </TASK> The underlying issue is that we recurse during the original page table move, but not during the recovery move. Fix it by checking for both VMAs and performing the check before the pmd_none() sanity check. Add a new helper where we perform+document that check for the PMD and PUD level. Thanks to Harry for bisecting. Link: https://lkml.kernel.org/r/20250818175358.1184757-1-david@redhat.com Fixes: 0cef0bb836e3 ("mm: clear uffd-wp PTE/PMD state on mremap()") Signed-off-by: David Hildenbrand <david(a)redhat.com> Reported-by: syzbot+4d9a13f0797c46a29e42(a)syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/689bb893.050a0220.7f033.013a.GAE@google.com Tested-by: Harry Yoo <harry.yoo(a)oracle.com> Cc: "Liam R. Howlett" <Liam.Howlett(a)oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Jann Horn <jannh(a)google.com> Cc: Pedro Falcato <pfalcato(a)suse.de> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/mremap.c | 41 +++++++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 18 deletions(-) --- a/mm/mremap.c~mm-mremap-fix-warn-with-uffd-that-has-remap-events-disabled +++ a/mm/mremap.c @@ -323,6 +323,25 @@ static inline bool arch_supports_page_ta } #endif +static inline bool uffd_supports_page_table_move(struct pagetable_move_control *pmc) +{ + /* + * If we are moving a VMA that has uffd-wp registered but with + * remap events disabled (new VMA will not be registered with uffd), we + * need to ensure that the uffd-wp state is cleared from all pgtables. + * This means recursing into lower page tables in move_page_tables(). + * + * We might get called with VMAs reversed when recovering from a + * failed page table move. In that case, the + * "old"-but-actually-"originally new" VMA during recovery will not have + * a uffd context. Recursing into lower page tables during the original + * move but not during the recovery move will cause trouble, because we + * run into already-existing page tables. So check both VMAs. + */ + return !vma_has_uffd_without_event_remap(pmc->old) && + !vma_has_uffd_without_event_remap(pmc->new); +} + #ifdef CONFIG_HAVE_MOVE_PMD static bool move_normal_pmd(struct pagetable_move_control *pmc, pmd_t *old_pmd, pmd_t *new_pmd) @@ -335,6 +354,8 @@ static bool move_normal_pmd(struct paget if (!arch_supports_page_table_move()) return false; + if (!uffd_supports_page_table_move(pmc)) + return false; /* * The destination pmd shouldn't be established, free_pgtables() * should have released it. @@ -361,15 +382,6 @@ static bool move_normal_pmd(struct paget if (WARN_ON_ONCE(!pmd_none(*new_pmd))) return false; - /* If this pmd belongs to a uffd vma with remap events disabled, we need - * to ensure that the uffd-wp state is cleared from all pgtables. This - * means recursing into lower page tables in move_page_tables(), and we - * can reuse the existing code if we simply treat the entry as "not - * moved". - */ - if (vma_has_uffd_without_event_remap(vma)) - return false; - /* * We don't have to worry about the ordering of src and dst * ptlocks because exclusive mmap_lock prevents deadlock. @@ -418,6 +430,8 @@ static bool move_normal_pud(struct paget if (!arch_supports_page_table_move()) return false; + if (!uffd_supports_page_table_move(pmc)) + return false; /* * The destination pud shouldn't be established, free_pgtables() * should have released it. @@ -425,15 +439,6 @@ static bool move_normal_pud(struct paget if (WARN_ON_ONCE(!pud_none(*new_pud))) return false; - /* If this pud belongs to a uffd vma with remap events disabled, we need - * to ensure that the uffd-wp state is cleared from all pgtables. This - * means recursing into lower page tables in move_page_tables(), and we - * can reuse the existing code if we simply treat the entry as "not - * moved". - */ - if (vma_has_uffd_without_event_remap(vma)) - return false; - /* * We don't have to worry about the ordering of src and dst * ptlocks because exclusive mmap_lock prevents deadlock. _ Patches currently in -mm which might be from david(a)redhat.com are mm-migrate-remove-migratepage_unmap.patch mm-migrate-remove-migratepage_unmap-fix.patch treewide-remove-migratepage_success.patch mm-huge_memory-move-more-common-code-into-insert_pmd.patch mm-huge_memory-move-more-common-code-into-insert_pud.patch mm-huge_memory-support-huge-zero-folio-in-vmf_insert_folio_pmd.patch fs-dax-use-vmf_insert_folio_pmd-to-insert-the-huge-zero-folio.patch mm-huge_memory-mark-pmd-mappings-of-the-huge-zero-folio-special.patch powerpc-ptdump-rename-struct-pgtable_level-to-struct-ptdump_pglevel.patch mm-rmap-convert-enum-rmap_level-to-enum-pgtable_level.patch mm-memory-convert-print_bad_pte-to-print_bad_page_map.patch mm-memory-factor-out-common-code-from-vm_normal_page_.patch mm-introduce-and-use-vm_normal_page_pud.patch mm-rename-vm_ops-find_special_page-to-vm_ops-find_normal_page.patch prctl-extend-pr_set_thp_disable-to-optionally-exclude-vm_hugepage.patch mm-huge_memory-convert-tva_flags-to-enum-tva_type.patch mm-huge_memory-respect-madv_collapse-with-pr_thp_disable_except_advised.patch

3 months, 1 week

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[merged mm-hotfixes-stable] mm-damon-core-fix-damos_commit_filter-not-changing-allow.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/damon/core: fix damos_commit_filter not changing allow has been removed from the -mm tree. Its filename was mm-damon-core-fix-damos_commit_filter-not-changing-allow.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Sang-Heon Jeon <ekffu200098(a)gmail.com> Subject: mm/damon/core: fix damos_commit_filter not changing allow Date: Sat, 16 Aug 2025 10:51:16 +0900 Current damos_commit_filter() does not persist the `allow' value of the filter. As a result, changing the `allow' value of a filter and committing doesn't change the `allow' value. Add the missing `allow' value update, so committing the filter persistently changes the `allow' value well. Link: https://lkml.kernel.org/r/20250816015116.194589-1-ekffu200098@gmail.com Fixes: fe6d7fdd6249 ("mm/damon/core: add damos_filter->allow field") Signed-off-by: Sang-Heon Jeon <ekffu200098(a)gmail.com> Reviewed-by: SeongJae Park <sj(a)kernel.org> Cc: <stable(a)vger.kernel.org> [6.14.x] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/damon/core.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/damon/core.c~mm-damon-core-fix-damos_commit_filter-not-changing-allow +++ a/mm/damon/core.c @@ -883,6 +883,7 @@ static void damos_commit_filter( { dst->type = src->type; dst->matching = src->matching; + dst->allow = src->allow; damos_commit_filter_arg(dst, src); } _ Patches currently in -mm which might be from ekffu200098(a)gmail.com are mm-damon-core-set-quota-charged_from-to-jiffies-at-first-charge-window.patch mm-damon-update-expired-description-of-damos_action.patch docs-mm-damon-design-fix-typo-s-sz_trtied-sz_tried.patch selftests-damon-test-no-op-commit-broke-damon-status.patch selftests-damon-test-no-op-commit-broke-damon-status-fix.patch mm-damon-tests-core-kunit-add-damos_commit_filter-test.patch

3 months, 1 week

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[merged mm-hotfixes-stable] mm-memory-failure-fix-infinite-uce-for-vm_pfnmap-pfn.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn has been removed from the -mm tree. Its filename was mm-memory-failure-fix-infinite-uce-for-vm_pfnmap-pfn.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Jinjiang Tu <tujinjiang(a)huawei.com> Subject: mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn Date: Fri, 15 Aug 2025 15:32:09 +0800 When memory_failure() is called for a already hwpoisoned pfn, kill_accessing_process() will be called to kill current task. However, if the vma of the accessing vaddr is VM_PFNMAP, walk_page_range() will skip the vma in walk_page_test() and return 0. Before commit aaf99ac2ceb7 ("mm/hwpoison: do not send SIGBUS to processes with recovered clean pages"), kill_accessing_process() will return EFAULT. For x86, the current task will be killed in kill_me_maybe(). However, after this commit, kill_accessing_process() simplies return 0, that means UCE is handled properly, but it doesn't actually. In such case, the user task will trigger UCE infinitely. To fix it, add .test_walk callback for hwpoison_walk_ops to scan all vmas. Link: https://lkml.kernel.org/r/20250815073209.1984582-1-tujinjiang@huawei.com Fixes: aaf99ac2ceb7 ("mm/hwpoison: do not send SIGBUS to processes with recovered clean pages") Signed-off-by: Jinjiang Tu <tujinjiang(a)huawei.com> Acked-by: David Hildenbrand <david(a)redhat.com> Acked-by: Miaohe Lin <linmiaohe(a)huawei.com> Reviewed-by: Jane Chu <jane.chu(a)oracle.com> Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com> Cc: Naoya Horiguchi <nao.horiguchi(a)gmail.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Shuai Xue <xueshuai(a)linux.alibaba.com> Cc: Zi Yan <ziy(a)nvidia.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/memory-failure.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/mm/memory-failure.c~mm-memory-failure-fix-infinite-uce-for-vm_pfnmap-pfn +++ a/mm/memory-failure.c @@ -853,9 +853,17 @@ static int hwpoison_hugetlb_range(pte_t #define hwpoison_hugetlb_range NULL #endif +static int hwpoison_test_walk(unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + /* We also want to consider pages mapped into VM_PFNMAP. */ + return 0; +} + static const struct mm_walk_ops hwpoison_walk_ops = { .pmd_entry = hwpoison_pte_range, .hugetlb_entry = hwpoison_hugetlb_range, + .test_walk = hwpoison_test_walk, .walk_lock = PGWALK_RDLOCK, }; _ Patches currently in -mm which might be from tujinjiang(a)huawei.com are mm-memory_hotplug-fix-hwpoisoned-large-folio-handling-in-do_migrate_range.patch

3 months, 1 week

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[merged mm-hotfixes-stable] iov_iter-iterate_folioq-fix-handling-of-offset-=-folio-size.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: iov_iter: iterate_folioq: fix handling of offset >= folio size has been removed from the -mm tree. Its filename was iov_iter-iterate_folioq-fix-handling-of-offset-=-folio-size.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Dominique Martinet <asmadeus(a)codewreck.org> Subject: iov_iter: iterate_folioq: fix handling of offset >= folio size Date: Wed, 13 Aug 2025 15:04:55 +0900 It's apparently possible to get an iov advanced all the way up to the end of the current page we're looking at, e.g. (gdb) p *iter $24 = {iter_type = 4 '\004', nofault = false, data_source = false, iov_offset = 4096, {__ubuf_iovec = { iov_base = 0xffff88800f5bc000, iov_len = 655}, {{__iov = 0xffff88800f5bc000, kvec = 0xffff88800f5bc000, bvec = 0xffff88800f5bc000, folioq = 0xffff88800f5bc000, xarray = 0xffff88800f5bc000, ubuf = 0xffff88800f5bc000}, count = 655}}, {nr_segs = 2, folioq_slot = 2 '\002', xarray_start = 2}} Where iov_offset is 4k with 4k-sized folios This should have been fine because we're only in the 2nd slot and there's another one after this, but iterate_folioq should not try to map a folio that skips the whole size, and more importantly part here does not end up zero (because 'PAGE_SIZE - skip % PAGE_SIZE' ends up PAGE_SIZE and not zero..), so skip forward to the "advance to next folio" code Link: https://lkml.kernel.org/r/20250813-iot_iter_folio-v3-0-a0ffad2b665a@codewre… Link: https://lkml.kernel.org/r/20250813-iot_iter_folio-v3-1-a0ffad2b665a@codewre… Signed-off-by: Dominique Martinet <asmadeus(a)codewreck.org> Fixes: db0aa2e9566f ("mm: Define struct folio_queue and ITER_FOLIOQ to handle a sequence of folios") Reported-by: Maximilian Bosch <maximilian(a)mbosch.me> Reported-by: Ryan Lahfa <ryan(a)lahfa.xyz> Reported-by: Christian Theune <ct(a)flyingcircus.io> Reported-by: Arnout Engelen <arnout(a)bzzt.net> Link: https://lkml.kernel.org/r/D4LHHUNLG79Y.12PI0X6BEHRHW@mbosch.me/ Acked-by: David Howells <dhowells(a)redhat.com> Cc: Al Viro <viro(a)zeniv.linux.org.uk> Cc: Christian Brauner <brauner(a)kernel.org> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> [6.12+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/iov_iter.h | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) --- a/include/linux/iov_iter.h~iov_iter-iterate_folioq-fix-handling-of-offset-=-folio-size +++ a/include/linux/iov_iter.h @@ -160,7 +160,7 @@ size_t iterate_folioq(struct iov_iter *i do { struct folio *folio = folioq_folio(folioq, slot); - size_t part, remain, consumed; + size_t part, remain = 0, consumed; size_t fsize; void *base; @@ -168,14 +168,16 @@ size_t iterate_folioq(struct iov_iter *i break; fsize = folioq_folio_size(folioq, slot); - base = kmap_local_folio(folio, skip); - part = umin(len, PAGE_SIZE - skip % PAGE_SIZE); - remain = step(base, progress, part, priv, priv2); - kunmap_local(base); - consumed = part - remain; - len -= consumed; - progress += consumed; - skip += consumed; + if (skip < fsize) { + base = kmap_local_folio(folio, skip); + part = umin(len, PAGE_SIZE - skip % PAGE_SIZE); + remain = step(base, progress, part, priv, priv2); + kunmap_local(base); + consumed = part - remain; + len -= consumed; + progress += consumed; + skip += consumed; + } if (skip >= fsize) { skip = 0; slot++; _ Patches currently in -mm which might be from asmadeus(a)codewreck.org are

3 months, 1 week

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[merged mm-hotfixes-stable] mm-damon-core-fix-commit_ops_filters-by-using-correct-nth-function.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/damon/core: fix commit_ops_filters by using correct nth function has been removed from the -mm tree. Its filename was mm-damon-core-fix-commit_ops_filters-by-using-correct-nth-function.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Sang-Heon Jeon <ekffu200098(a)gmail.com> Subject: mm/damon/core: fix commit_ops_filters by using correct nth function Date: Sun, 10 Aug 2025 21:42:01 +0900 damos_commit_ops_filters() incorrectly uses damos_nth_filter() which iterates core_filters. As a result, performing a commit unintentionally corrupts ops_filters. Add damos_nth_ops_filter() which iterates ops_filters. Use this function to fix issues caused by wrong iteration. Link: https://lkml.kernel.org/r/20250810124201.15743-1-ekffu200098@gmail.com Fixes: 3607cc590f18 ("mm/damon/core: support committing ops_filters") # 6.15.x Signed-off-by: Sang-Heon Jeon <ekffu200098(a)gmail.com> Reviewed-by: SeongJae Park <sj(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/damon/core.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) --- a/mm/damon/core.c~mm-damon-core-fix-commit_ops_filters-by-using-correct-nth-function +++ a/mm/damon/core.c @@ -845,6 +845,18 @@ static struct damos_filter *damos_nth_fi return NULL; } +static struct damos_filter *damos_nth_ops_filter(int n, struct damos *s) +{ + struct damos_filter *filter; + int i = 0; + + damos_for_each_ops_filter(filter, s) { + if (i++ == n) + return filter; + } + return NULL; +} + static void damos_commit_filter_arg( struct damos_filter *dst, struct damos_filter *src) { @@ -908,7 +920,7 @@ static int damos_commit_ops_filters(stru int i = 0, j = 0; damos_for_each_ops_filter_safe(dst_filter, next, dst) { - src_filter = damos_nth_filter(i++, src); + src_filter = damos_nth_ops_filter(i++, src); if (src_filter) damos_commit_filter(dst_filter, src_filter); else _ Patches currently in -mm which might be from ekffu200098(a)gmail.com are mm-damon-core-set-quota-charged_from-to-jiffies-at-first-charge-window.patch mm-damon-update-expired-description-of-damos_action.patch docs-mm-damon-design-fix-typo-s-sz_trtied-sz_tried.patch selftests-damon-test-no-op-commit-broke-damon-status.patch selftests-damon-test-no-op-commit-broke-damon-status-fix.patch mm-damon-tests-core-kunit-add-damos_commit_filter-test.patch

3 months, 1 week

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[merged mm-hotfixes-stable] mm-debug_vm_pgtable-clear-page-table-entries-at-destroy_args.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/debug_vm_pgtable: clear page table entries at destroy_args() has been removed from the -mm tree. Its filename was mm-debug_vm_pgtable-clear-page-table-entries-at-destroy_args.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: "Herton R. Krzesinski" <herton(a)redhat.com> Subject: mm/debug_vm_pgtable: clear page table entries at destroy_args() Date: Thu, 31 Jul 2025 18:40:51 -0300 The mm/debug_vm_pagetable test allocates manually page table entries for the tests it runs, using also its manually allocated mm_struct. That in itself is ok, but when it exits, at destroy_args() it fails to clear those entries with the *_clear functions. The problem is that leaves stale entries. If another process allocates an mm_struct with a pgd at the same address, it may end up running into the stale entry. This is happening in practice on a debug kernel with CONFIG_DEBUG_VM_PGTABLE=y, for example this is the output with some extra debugging I added (it prints a warning trace if pgtables_bytes goes negative, in addition to the warning at check_mm() function): [ 2.539353] debug_vm_pgtable: [get_random_vaddr ]: random_vaddr is 0x7ea247140000 [ 2.539366] kmem_cache info [ 2.539374] kmem_cachep 0x000000002ce82385 - freelist 0x0000000000000000 - offset 0x508 [ 2.539447] debug_vm_pgtable: [init_args ]: args->mm is 0x000000002267cc9e (...) [ 2.552800] WARNING: CPU: 5 PID: 116 at include/linux/mm.h:2841 free_pud_range+0x8bc/0x8d0 [ 2.552816] Modules linked in: [ 2.552843] CPU: 5 UID: 0 PID: 116 Comm: modprobe Not tainted 6.12.0-105.debug_vm2.el10.ppc64le+debug #1 VOLUNTARY [ 2.552859] Hardware name: IBM,9009-41A POWER9 (architected) 0x4e0202 0xf000005 of:IBM,FW910.00 (VL910_062) hv:phyp pSeries [ 2.552872] NIP: c0000000007eef3c LR: c0000000007eef30 CTR: c0000000003d8c90 [ 2.552885] REGS: c0000000622e73b0 TRAP: 0700 Not tainted (6.12.0-105.debug_vm2.el10.ppc64le+debug) [ 2.552899] MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 24002822 XER: 0000000a [ 2.552954] CFAR: c0000000008f03f0 IRQMASK: 0 [ 2.552954] GPR00: c0000000007eef30 c0000000622e7650 c000000002b1ac00 0000000000000001 [ 2.552954] GPR04: 0000000000000008 0000000000000000 c0000000007eef30 ffffffffffffffff [ 2.552954] GPR08: 00000000ffff00f5 0000000000000001 0000000000000048 0000000000004000 [ 2.552954] GPR12: 00000003fa440000 c000000017ffa300 c0000000051d9f80 ffffffffffffffdb [ 2.552954] GPR16: 0000000000000000 0000000000000008 000000000000000a 60000000000000e0 [ 2.552954] GPR20: 4080000000000000 c0000000113af038 00007fffcf130000 0000700000000000 [ 2.552954] GPR24: c000000062a6a000 0000000000000001 8000000062a68000 0000000000000001 [ 2.552954] GPR28: 000000000000000a c000000062ebc600 0000000000002000 c000000062ebc760 [ 2.553170] NIP [c0000000007eef3c] free_pud_range+0x8bc/0x8d0 [ 2.553185] LR [c0000000007eef30] free_pud_range+0x8b0/0x8d0 [ 2.553199] Call Trace: [ 2.553207] [c0000000622e7650] [c0000000007eef30] free_pud_range+0x8b0/0x8d0 (unreliable) [ 2.553229] [c0000000622e7750] [c0000000007f40b4] free_pgd_range+0x284/0x3b0 [ 2.553248] [c0000000622e7800] [c0000000007f4630] free_pgtables+0x450/0x570 [ 2.553274] [c0000000622e78e0] [c0000000008161c0] exit_mmap+0x250/0x650 [ 2.553292] [c0000000622e7a30] [c0000000001b95b8] __mmput+0x98/0x290 [ 2.558344] [c0000000622e7a80] [c0000000001d1018] exit_mm+0x118/0x1b0 [ 2.558361] [c0000000622e7ac0] [c0000000001d141c] do_exit+0x2ec/0x870 [ 2.558376] [c0000000622e7b60] [c0000000001d1ca8] do_group_exit+0x88/0x150 [ 2.558391] [c0000000622e7bb0] [c0000000001d1db8] sys_exit_group+0x48/0x50 [ 2.558407] [c0000000622e7be0] [c00000000003d810] system_call_exception+0x1e0/0x4c0 [ 2.558423] [c0000000622e7e50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec (...) [ 2.558892] ---[ end trace 0000000000000000 ]--- [ 2.559022] BUG: Bad rss-counter state mm:000000002267cc9e type:MM_ANONPAGES val:1 [ 2.559037] BUG: non-zero pgtables_bytes on freeing mm: -6144 Here the modprobe process ended up with an allocated mm_struct from the mm_struct slab that was used before by the debug_vm_pgtable test. That is not a problem, since the mm_struct is initialized again etc., however, if it ends up using the same pgd table, it bumps into the old stale entry when clearing/freeing the page table entries, so it tries to free an entry already gone (that one which was allocated by the debug_vm_pgtable test), which also explains the negative pgtables_bytes since it's accounting for not allocated entries in the current process. As far as I looked pgd_{alloc,free} etc. does not clear entries, and clearing of the entries is explicitly done in the free_pgtables-> free_pgd_range->free_p4d_range->free_pud_range->free_pmd_range-> free_pte_range path. However, the debug_vm_pgtable test does not call free_pgtables, since it allocates mm_struct and entries manually for its test and eg. not goes through page faults. So it also should clear manually the entries before exit at destroy_args(). This problem was noticed on a reboot X number of times test being done on a powerpc host, with a debug kernel with CONFIG_DEBUG_VM_PGTABLE enabled. Depends on the system, but on a 100 times reboot loop the problem could manifest once or twice, if a process ends up getting the right mm->pgd entry with the stale entries used by mm/debug_vm_pagetable. After using this patch, I couldn't reproduce/experience the problems anymore. I was able to reproduce the problem as well on latest upstream kernel (6.16). I also modified destroy_args() to use mmput() instead of mmdrop(), there is no reason to hold mm_users reference and not release the mm_struct entirely, and in the output above with my debugging prints I already had patched it to use mmput, it did not fix the problem, but helped in the debugging as well. Link: https://lkml.kernel.org/r/20250731214051.4115182-1-herton@redhat.com Fixes: 3c9b84f044a9 ("mm/debug_vm_pgtable: introduce struct pgtable_debug_args") Signed-off-by: Herton R. Krzesinski <herton(a)redhat.com> Cc: Anshuman Khandual <anshuman.khandual(a)arm.com> Cc: Christophe Leroy <christophe.leroy(a)csgroup.eu> Cc: Gavin Shan <gshan(a)redhat.com> Cc: Gerald Schaefer <gerald.schaefer(a)linux.ibm.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/debug_vm_pgtable.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-clear-page-table-entries-at-destroy_args +++ a/mm/debug_vm_pgtable.c @@ -990,29 +990,34 @@ static void __init destroy_args(struct p /* Free page table entries */ if (args->start_ptep) { + pmd_clear(args->pmdp); pte_free(args->mm, args->start_ptep); mm_dec_nr_ptes(args->mm); } if (args->start_pmdp) { + pud_clear(args->pudp); pmd_free(args->mm, args->start_pmdp); mm_dec_nr_pmds(args->mm); } if (args->start_pudp) { + p4d_clear(args->p4dp); pud_free(args->mm, args->start_pudp); mm_dec_nr_puds(args->mm); } - if (args->start_p4dp) + if (args->start_p4dp) { + pgd_clear(args->pgdp); p4d_free(args->mm, args->start_p4dp); + } /* Free vma and mm struct */ if (args->vma) vm_area_free(args->vma); if (args->mm) - mmdrop(args->mm); + mmput(args->mm); } static struct page * __init _ Patches currently in -mm which might be from herton(a)redhat.com are

3 months, 1 week

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[merged mm-hotfixes-stable] squashfs-fix-memory-leak-in-squashfs_fill_super.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: squashfs: fix memory leak in squashfs_fill_super has been removed from the -mm tree. Its filename was squashfs-fix-memory-leak-in-squashfs_fill_super.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Phillip Lougher <phillip(a)squashfs.org.uk> Subject: squashfs: fix memory leak in squashfs_fill_super Date: Mon, 11 Aug 2025 23:37:40 +0100 If sb_min_blocksize returns 0, squashfs_fill_super exits without freeing allocated memory (sb->s_fs_info). Fix this by moving the call to sb_min_blocksize to before memory is allocated. Link: https://lkml.kernel.org/r/20250811223740.110392-1-phillip@squashfs.org.uk Fixes: 734aa85390ea ("Squashfs: check return result of sb_min_blocksize") Signed-off-by: Phillip Lougher <phillip(a)squashfs.org.uk> Reported-by: Scott GUO <scottzhguo(a)tencent.com> Closes: https://lore.kernel.org/all/20250811061921.3807353-1-scott_gzh@163.com Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/squashfs/super.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) --- a/fs/squashfs/super.c~squashfs-fix-memory-leak-in-squashfs_fill_super +++ a/fs/squashfs/super.c @@ -187,10 +187,15 @@ static int squashfs_fill_super(struct su unsigned short flags; unsigned int fragments; u64 lookup_table_start, xattr_id_table_start, next_table; - int err; + int err, devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); TRACE("Entered squashfs_fill_superblock\n"); + if (!devblksize) { + errorf(fc, "squashfs: unable to set blocksize\n"); + return -EINVAL; + } + sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL); if (sb->s_fs_info == NULL) { ERROR("Failed to allocate squashfs_sb_info\n"); @@ -201,12 +206,7 @@ static int squashfs_fill_super(struct su msblk->panic_on_errors = (opts->errors == Opt_errors_panic); - msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); - if (!msblk->devblksize) { - errorf(fc, "squashfs: unable to set blocksize\n"); - return -EINVAL; - } - + msblk->devblksize = devblksize; msblk->devblksize_log2 = ffz(~msblk->devblksize); mutex_init(&msblk->meta_index_mutex); _ Patches currently in -mm which might be from phillip(a)squashfs.org.uk are

3 months, 1 week

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[merged mm-hotfixes-stable] kho-warn-if-kho-is-disabled-due-to-an-error.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: kho: warn if KHO is disabled due to an error has been removed from the -mm tree. Its filename was kho-warn-if-kho-is-disabled-due-to-an-error.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Pasha Tatashin <pasha.tatashin(a)soleen.com> Subject: kho: warn if KHO is disabled due to an error Date: Fri, 8 Aug 2025 20:18:04 +0000 During boot scratch area is allocated based on command line parameters or auto calculated. However, scratch area may fail to allocate, and in that case KHO is disabled. Currently, no warning is printed that KHO is disabled, which makes it confusing for the end user to figure out why KHO is not available. Add the missing warning message. Link: https://lkml.kernel.org/r/20250808201804.772010-4-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin(a)soleen.com> Acked-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Acked-by: Pratyush Yadav <pratyush(a)kernel.org> Cc: Alexander Graf <graf(a)amazon.com> Cc: Arnd Bergmann <arnd(a)arndb.de> Cc: Baoquan He <bhe(a)redhat.com> Cc: Changyuan Lyu <changyuanl(a)google.com> Cc: Coiby Xu <coxu(a)redhat.com> Cc: Dave Vasilevsky <dave(a)vasilevsky.ca> Cc: Eric Biggers <ebiggers(a)google.com> Cc: Kees Cook <kees(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- kernel/kexec_handover.c | 1 + 1 file changed, 1 insertion(+) --- a/kernel/kexec_handover.c~kho-warn-if-kho-is-disabled-due-to-an-error +++ a/kernel/kexec_handover.c @@ -564,6 +564,7 @@ err_free_scratch_areas: err_free_scratch_desc: memblock_free(kho_scratch, kho_scratch_cnt * sizeof(*kho_scratch)); err_disable_kho: + pr_warn("Failed to reserve scratch area, disabling kexec handover\n"); kho_enable = false; } _ Patches currently in -mm which might be from pasha.tatashin(a)soleen.com are

3 months, 1 week

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[merged mm-hotfixes-stable] kho-mm-dont-allow-deferred-struct-page-with-kho.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: kho: mm: don't allow deferred struct page with KHO has been removed from the -mm tree. Its filename was kho-mm-dont-allow-deferred-struct-page-with-kho.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Pasha Tatashin <pasha.tatashin(a)soleen.com> Subject: kho: mm: don't allow deferred struct page with KHO Date: Fri, 8 Aug 2025 20:18:03 +0000 KHO uses struct pages for the preserved memory early in boot, however, with deferred struct page initialization, only a small portion of memory has properly initialized struct pages. This problem was detected where vmemmap is poisoned, and illegal flag combinations are detected. Don't allow them to be enabled together, and later we will have to teach KHO to work properly with deferred struct page init kernel feature. Link: https://lkml.kernel.org/r/20250808201804.772010-3-pasha.tatashin@soleen.com Fixes: 4e1d010e3bda ("kexec: add config option for KHO") Signed-off-by: Pasha Tatashin <pasha.tatashin(a)soleen.com> Acked-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Acked-by: Pratyush Yadav <pratyush(a)kernel.org> Cc: Alexander Graf <graf(a)amazon.com> Cc: Arnd Bergmann <arnd(a)arndb.de> Cc: Baoquan He <bhe(a)redhat.com> Cc: Changyuan Lyu <changyuanl(a)google.com> Cc: Coiby Xu <coxu(a)redhat.com> Cc: Dave Vasilevsky <dave(a)vasilevsky.ca> Cc: Eric Biggers <ebiggers(a)google.com> Cc: Kees Cook <kees(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- kernel/Kconfig.kexec | 1 + 1 file changed, 1 insertion(+) --- a/kernel/Kconfig.kexec~kho-mm-dont-allow-deferred-struct-page-with-kho +++ a/kernel/Kconfig.kexec @@ -97,6 +97,7 @@ config KEXEC_JUMP config KEXEC_HANDOVER bool "kexec handover" depends on ARCH_SUPPORTS_KEXEC_HANDOVER && ARCH_SUPPORTS_KEXEC_FILE + depends on !DEFERRED_STRUCT_PAGE_INIT select MEMBLOCK_KHO_SCRATCH select KEXEC_FILE select DEBUG_FS _ Patches currently in -mm which might be from pasha.tatashin(a)soleen.com are

3 months, 1 week

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[merged mm-hotfixes-stable] kho-init-new_physxa-phys_bits-to-fix-lockdep.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: kho: init new_physxa->phys_bits to fix lockdep has been removed from the -mm tree. Its filename was kho-init-new_physxa-phys_bits-to-fix-lockdep.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Pasha Tatashin <pasha.tatashin(a)soleen.com> Subject: kho: init new_physxa->phys_bits to fix lockdep Date: Fri, 8 Aug 2025 20:18:02 +0000 Patch series "Several KHO Hotfixes". Three unrelated fixes for Kexec Handover. This patch (of 3): Lockdep shows the following warning: INFO: trying to register non-static key. The code is fine but needs lockdep annotation, or maybe you didn't initialize this object before use? turning off the locking correctness validator. [<ffffffff810133a6>] dump_stack_lvl+0x66/0xa0 [<ffffffff8136012c>] assign_lock_key+0x10c/0x120 [<ffffffff81358bb4>] register_lock_class+0xf4/0x2f0 [<ffffffff813597ff>] __lock_acquire+0x7f/0x2c40 [<ffffffff81360cb0>] ? __pfx_hlock_conflict+0x10/0x10 [<ffffffff811707be>] ? native_flush_tlb_global+0x8e/0xa0 [<ffffffff8117096e>] ? __flush_tlb_all+0x4e/0xa0 [<ffffffff81172fc2>] ? __kernel_map_pages+0x112/0x140 [<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0 [<ffffffff81359556>] lock_acquire+0xe6/0x280 [<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0 [<ffffffff8100b9e0>] _raw_spin_lock+0x30/0x40 [<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0 [<ffffffff813ec327>] xa_load_or_alloc+0x67/0xe0 [<ffffffff813eb4c0>] kho_preserve_folio+0x90/0x100 [<ffffffff813ebb7f>] __kho_finalize+0xcf/0x400 [<ffffffff813ebef4>] kho_finalize+0x34/0x70 This is becase xa has its own lock, that is not initialized in xa_load_or_alloc. Modifiy __kho_preserve_order(), to properly call xa_init(&new_physxa->phys_bits); Link: https://lkml.kernel.org/r/20250808201804.772010-2-pasha.tatashin@soleen.com Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") Signed-off-by: Pasha Tatashin <pasha.tatashin(a)soleen.com> Acked-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Cc: Alexander Graf <graf(a)amazon.com> Cc: Arnd Bergmann <arnd(a)arndb.de> Cc: Baoquan He <bhe(a)redhat.com> Cc: Changyuan Lyu <changyuanl(a)google.com> Cc: Coiby Xu <coxu(a)redhat.com> Cc: Dave Vasilevsky <dave(a)vasilevsky.ca> Cc: Eric Biggers <ebiggers(a)google.com> Cc: Kees Cook <kees(a)kernel.org> Cc: Pratyush Yadav <pratyush(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- kernel/kexec_handover.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) --- a/kernel/kexec_handover.c~kho-init-new_physxa-phys_bits-to-fix-lockdep +++ a/kernel/kexec_handover.c @@ -144,14 +144,34 @@ static int __kho_preserve_order(struct k unsigned int order) { struct kho_mem_phys_bits *bits; - struct kho_mem_phys *physxa; + struct kho_mem_phys *physxa, *new_physxa; const unsigned long pfn_high = pfn >> order; might_sleep(); - physxa = xa_load_or_alloc(&track->orders, order, sizeof(*physxa)); - if (IS_ERR(physxa)) - return PTR_ERR(physxa); + physxa = xa_load(&track->orders, order); + if (!physxa) { + int err; + + new_physxa = kzalloc(sizeof(*physxa), GFP_KERNEL); + if (!new_physxa) + return -ENOMEM; + + xa_init(&new_physxa->phys_bits); + physxa = xa_cmpxchg(&track->orders, order, NULL, new_physxa, + GFP_KERNEL); + + err = xa_err(physxa); + if (err || physxa) { + xa_destroy(&new_physxa->phys_bits); + kfree(new_physxa); + + if (err) + return err; + } else { + physxa = new_physxa; + } + } bits = xa_load_or_alloc(&physxa->phys_bits, pfn_high / PRESERVE_BITS, sizeof(*bits)); _ Patches currently in -mm which might be from pasha.tatashin(a)soleen.com are

3 months, 1 week

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