From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7BAEF31715A for ; Tue, 15 Sep 2026 01:10:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789434605; cv=none; b=hwg+Gs+3dW4tUsRHcWlh/vk6iedmmcoH/Gh+C3KxFaDg97KLulEny0zTkbhYJmBU7y+PQzHzEVox/Cs/2MtC4ad5WPRpP28TaSqEPbFRwl4xGDJ2IJc75ZZEsRyhEya2/vSqRyfRSU9qOWta0DVoohIx3ftadK88em+LZxRAalg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789434605; c=relaxed/simple; bh=o3lUqdjIQVK7DCP9drH9pG8vNkkMNESdPFIeI36KcHE=; h=Date:To:From:Subject:Message-Id; b=Iqstw+gN6shNOo8wHVGvOHISpH4nafv0tI6apU+FgeRmpJ7lxPcfiNUNXm0w3pImXoQ+53q6usddbMklIawIz/cCvq5pt9cfzl5cVtnIT2IjvyBfy/SG95dRFYsFAQRxtq2r4okNzAIStkcd4n+z/eoD+8jgS/7yo0z15mBEt5Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=T2Cqano9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="T2Cqano9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F0881F000FF; Tue, 15 Sep 2026 01:10:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789434601; bh=AgxDidxJ7sC/HraVDk0nrPMBQfnQHr/rFedNIytE1DA=; h=Date:To:From:Subject; b=T2Cqano9FZG80+kq8dAUY6N0ztxyAl4jlx4V8yfMPyWjn3L0TKkHHqAEYoWDmxgsp rEUpGMP9xdkm0ZeCDXkzDN80hf0K8Teh/539CcMNMn9gBdgGFzPtQ0lDwEnh9IQoJv Ik0f8e+hXX/GVd3J5dXGjXDS61Yx9XAuOk0PTb98= Date: Mon, 14 Sep 2026 18:10:00 -0700 To: mm-commits@vger.kernel.org,ljs@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-madvise-update-is_valid_guard_vma-to-use-vma_can_merge.patch added to mm-new branch Message-Id: <20260915011001.6F0881F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/madvise: update is_valid_guard_vma() to use vma_can_merge() has been added to the -mm mm-new branch. Its filename is mm-madvise-update-is_valid_guard_vma-to-use-vma_can_merge.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-madvise-update-is_valid_guard_vma-to-use-vma_can_merge.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: "Lorenzo Stoakes (ARM)" Subject: mm/madvise: update is_valid_guard_vma() to use vma_can_merge() Date: Mon, 14 Sep 2026 15:57:50 +0100 We currently disallow the installation of lightweight guard regions in VMAs whose flags intersect VMA_SPECIAL_FLAGS or VMA_HUGETLB_BIT, or VMA_LOCKED_BIT unless allow_locked is set. hugetlb VMAs set VMA_DONTEXPAND_BIT so this was already redundant, VMA_SPECIAL_FLAGS already sufficed. However, now that VMA_IO_BIT is only set if VMA_PFNMAP or VMA_MIXEDMAP_BIT is set, this check collapses to being the equivalent of !vma_can_merge(). Update is_valid_guard_vma() to reflect this. No functional change intended. Link: https://lore.kernel.org/20260914-b4-mmap-prepare-vma-flag-sanify-v2-30-7d9781ed5361@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton --- mm/madvise.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) --- a/mm/madvise.c~mm-madvise-update-is_valid_guard_vma-to-use-vma_can_merge +++ a/mm/madvise.c @@ -1221,19 +1221,25 @@ static long madvise_remove(struct madvis return error; } -static bool is_valid_guard_vma(struct vm_area_struct *vma, bool allow_locked) +static bool is_valid_guard_vma(const struct vm_area_struct *vma, + bool allow_locked) { - vm_flags_t disallowed = VM_SPECIAL | VM_HUGETLB; - /* - * A user could lock after setting a guard range but that's fine, as + * A user could lock after setting a guard range but that's fine as * they'd not be able to fault in. The issue arises when we try to zap * existing locked VMAs. We don't want to do that. */ - if (!allow_locked) - disallowed |= VM_LOCKED; + if (!allow_locked && vma_test(vma, VMA_LOCKED_BIT)) + return false; + /* + * Guard regions require a VMA whose page tables are managed solely by + * the core, which is also what merging requires, so disallow any flags + * that would prevent a merge. + */ + if (!vma_can_merge(vma)) + return false; - return !(vma->vm_flags & disallowed); + return true; } static bool is_guard_pte_marker(pte_t ptent) _ Patches currently in -mm which might be from ljs@kernel.org are mm-vmpressure-remove-window-size-todo.patch tools-testing-selftests-mm-add-missing-gitignore-entries.patch mm-move-drivers-char-memc-to-mm-char-memc.patch mm-implement-file_is_dev_zero-to-uniquely-identify-dev-zero.patch mm-vma-only-permit-map_private-dev-zero-to-be-mapped-anonymous.patch mm-vma-make-map_private-mapped-dev-zero-mappings-truly-anonymous.patch tools-testing-vma-add-test-to-assert-map_private-dev-zero-is-anon.patch tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests.patch mm-madvise-swap-in-cowd-map_private-file-mappings-on-madv_willneed.patch mm-huge_memory-zap-deposited-page-tables-after-an-rcu-grace-period.patch mm-enable-mmu_gather_rcu_table_free-for-most-2-level-architectures.patch mm-enable-mmu_gather_rcu_table_free-for-mmu-riscv.patch mm-enable-mmu_gather_rcu_table_free-for-mmu-arm.patch mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa.patch mm-enable-mmu_gather_rcu_table_free-for-sparc64.patch mm-enable-mmu_gather_rcu_table_free-for-m68k-coldfire.patch mm-enable-mmu_gather_rcu_table_free-for-sh-x2.patch mm-enable-mmu_gather_rcu_table_free-for-m68k-motorola.patch mm-enable-mmu_gather_rcu_table_free-for-sparc32.patch mm-make-userland-page-table-freeing-rcu-safe.patch mm-change-the-contract-for-free_pgtables-update-docs.patch mm-vma-fix-mmap_prepare-file-handling-remove-file_doesnt_need_get.patch mm-vma-predicate-setting-mmap_prepare-vma-fields-on-new-vma-alloc.patch mm-vma-introduce-and-use-vma_can_merge.patch mm-consistently-validate-vma-state-after-mmap-hooks.patch mm-vma-ensure-mmap_prepare-doesnt-set-actions-on-a-mergeable-vma.patch mm-make-map_kernel_pages_-internal-and-unexported.patch mm-vma-tidy-up-map-kernel-pages-enum-values.patch mm-add-mmap-action-for-discontiguous-kernel-page-mapping.patch docs-filesystems-update-mmap_prepare-docs-for-discontig-kernel-pgs.patch drivers-usb-mon-update-to-use-mmap_prepare-map-kernel-pages.patch infiniband-update-hfi1-to-use-remap_vmalloc_range.patch selinux-reject-writable-opens-of-policy-file-drop-mmap-shared-write-check.patch alsa-pcm-use-vm_insert_page-to-map-pcm-status-page.patch bpf-arena-mark-arena_map_mmap-mappings-vm_mixedmap.patch mm-vma-add-vma_is_kernel_owned-predicates.patch mm-vma-only-allow-mmap-to-clear-vma_maywrite_bit-if-kernel-owned.patch mm-vma-add-and-use-vma__is_fixed_mapping.patch scsi-sg-convert-mmap-hook-to-mmap_prepare-and-rework.patch fbdev-defio-assert-fbinfo_virtfb-drop-vm_io-add-vm_mixedmap.patch hsi-cmt_speech-convert-mmap-hook-to-mmap_prepare-refactor.patch mm-gup-error-out-early-on-vma_mayread_bit-vmas.patch uprobes-remove-vm_io-set-vm_mixedmap-for-mapped-kernel-pages.patch mm-mlock-clear-vma_locked_mask-over-mmap-callback.patch mm-mlock-eliminate-weird-vma_io_bit-abuse-and-simplify.patch mm-vma-enforce-that-only-kernel-owned-mappings-may-set-vma_io_bit.patch mm-remove-vma_io_bit-check-in-vma_is_kernel_owned.patch mm-remove-hugetlb_inlineh.patch mm-rename-is_vm_hugetlb_page-to-vma_is_hugetlb.patch mm-drop-some-redundant-checks-around-hugetlb-vmas.patch mm-madvise-update-is_valid_guard_vma-to-use-vma_can_merge.patch mm-vma-introduce-vma_is_persistent.patch mm-uffd-use-predicates-for-userfaultfd-checks.patch mm-madvise-use-predicates-for-madvise-madv_dofork.patch mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested.patch mm-eliminate-vma_special_flags-check-in-lru_gen_look_around.patch mm-avoid-use-of-vma_special_flags-in-migrate_vma_setup.patch mm-eliminate-vm_special-vma_special_flags.patch fuse-dax-do-not-set-vm_mixedmap.patch mm-huge_memory-remove-vma_is_special_huge.patch mm-vma-introduce-and-use-vma_can_gup.patch