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 73AA84E50C2 for ; Thu, 17 Sep 2026 21:10:28 +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=1789679430; cv=none; b=ShLn6/L7TkOoEe+GiOZkZIt/IRpcfjJ1gYig7IFc9KMODBGui8/cgpZvgWiQ/xCzmOjCyDgjIP1kXaiIJky1zzyHZfWiUPxMgB6N25ZDr/mAHVp3fGtZJaZYzXjk0bynEs3pZAGxVvlpITdzCWrqManso3YY18ts042MugoXPlA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789679430; c=relaxed/simple; bh=VagbIfY4e3mUgcHo2uIV4ttpbiwQZdxZj24alR4G+5g=; h=Date:To:From:Subject:Message-Id; b=Vdc2hW9UU2nqqZJurALriy/p19/UCxyLkgIgMkg8nTIhVfcBlLPECAy8/3RFI4moZcV4ywaXtNjG2lplllvzkmATciuigOu2yTMkrfFpz8W1RcmI7cNA5lLUWjn7zMgXkxshduiLH56oXaQuZUekTjf8cZBW3Ug5LwMaScUbpKs= 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=ayVj6ORC; 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="ayVj6ORC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 492CD1F00899; Thu, 17 Sep 2026 21:10:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789679428; bh=fyb3ofe3XE7PhGwIaNnDp6il3O+mrxp+ByxnXI8Vm+U=; h=Date:To:From:Subject; b=ayVj6ORCH8BdjMnkOGxcBJn6fr/xN4SB+8XnA2oZcOriTEESf/RrlxRF53vCLWaeN YYmn0WkmwO90dd/7x6YlZOIjkUnKFo/Anhiyrqp8JRT9q8q3F/Jg8u95wNRbbKv5fK dyncVtkJRH07EVEM6x63dgVc9FpynGAgYcu812cU= Date: Thu, 17 Sep 2026 14:10:27 -0700 To: mm-commits@vger.kernel.org,ljs@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-uffd-use-predicates-for-userfaultfd-checks.patch removed from -mm tree Message-Id: <20260917211028.492CD1F00899@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/uffd: use predicates for userfaultfd checks has been removed from the -mm tree. Its filename was mm-uffd-use-predicates-for-userfaultfd-checks.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: "Lorenzo Stoakes (ARM)" Subject: mm/uffd: use predicates for userfaultfd checks Date: Mon, 14 Sep 2026 15:57:52 +0100 Rather than directly checking VMA flags, use the newly introduced vma_is_kernel_owned() and vma_is_persistent() helpers in userfaultfd when assessing VMA suitability for userfaultfd and UFFDIO_MOVE. Update vma_move_compatible() so it's expressed in terms of VMA characteristics rather than arbitrary flags. Additionally, update the use of the deprecated VMA flag API when checking VMA_SHADOW_STACK_BIT. A VMA_IO_BIT check is no longer required but that is fine as a hard invariant has been established that only kernel-owned mappings may set VMA_IO_BIT so the check is now redundant. Link: https://lore.kernel.org/20260914-b4-mmap-prepare-vma-flag-sanify-v2-32-7d9781ed5361@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton --- mm/userfaultfd.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) --- a/mm/userfaultfd.c~mm-uffd-use-predicates-for-userfaultfd-checks +++ a/mm/userfaultfd.c @@ -1754,10 +1754,18 @@ static inline bool move_splits_huge_pmd( } #endif -static inline bool vma_move_compatible(struct vm_area_struct *vma) +static inline bool vma_move_compatible(const struct vm_area_struct *vma) { - return !(vma->vm_flags & (VM_PFNMAP | VM_IO | VM_HUGETLB | - VM_MIXEDMAP | VM_SHADOW_STACK)); + /* uffd is generally incompatible with kernel-owned mappings. */ + if (vma_is_kernel_owned(vma)) + return false; + /* The shadow stack should not be written to by userspace. */ + if (vma_test_single_mask(vma, VMA_SHADOW_STACK)) + return false; + /* hugetlb mappings cannot be safely moved. */ + if (vma_is_hugetlb(vma)) + return false; + return true; } static int validate_move_areas(struct userfaultfd_ctx *ctx, @@ -2146,10 +2154,11 @@ static bool vma_can_userfault(struct vm_ { const struct vm_uffd_ops *ops = vma_uffd_ops(vma); - if (vma->vm_flags & (VM_DROPPABLE | VM_SHADOW_STACK)) + /* Non-persistent memory is inherently not controllable by userspace. */ + if (!vma_is_persistent(vma)) return false; - - if (!vma_is_hugetlb(vma) && (vma->vm_flags & VM_SPECIAL)) + /* The shadow stack should not be written to by userspace. */ + if (vma_test_single_mask(vma, VMA_SHADOW_STACK)) return false; vm_flags &= __VM_UFFD_FLAGS; _ 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-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 mm-vma-const-ify-vma_assert_stabilised-and-associated-functions.patch mm-implement-and-use-vma_has_anon_rmap-silence-kcsan.patch mm-update-comments-to-refer-to-anon-rmap-rather-than-anon_vma.patch