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 999F7388879 for ; Sat, 10 Oct 2026 21:40:02 +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=1791668404; cv=none; b=FPsgO6D9K7YchCumW4rT5X8uta/5bAIRxo6cGvEhdgyALKPyWsg/d0J2kxdPiiU78PijnNYb00luRtDhwQvUC7VhIOKvZ7tFcSPaLwVZW4bjLqJZkLme6hl2A6WU82qiAf6BQOBrZFhyfOthJDGRVIYmw5T/Qgj/o4Aq9mS5LCo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791668404; c=relaxed/simple; bh=oEKwQ2evzD6mMD0kKnt+YuEz6TYYtADoQp6Tftt4BmQ=; h=Date:To:From:Subject:Message-Id; b=LAdtJElrOMpKq+WObQ5ALACbuG6IPdW0KQ/diBCL9BnG/pL2oX1F87UrunLMPFnousv0kIXTXwIokmS+8/TfgUbxphzVw66HWIC5fhsrRXmo0WEz6JeYXM1xDgDzmR/uxJG1mw7JNlmULk0XgHkyTjbKuai0HrfA3aCW4Ypx/sw= 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=vEbH8R6d; 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="vEbH8R6d" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 706F51F00893; Sat, 10 Oct 2026 21:40:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1791668402; bh=S5X1azMCvAsgFB8VdrTrFSpUpnT51VwfAYFoaVTAZLQ=; h=Date:To:From:Subject; b=vEbH8R6d5Wo9K1YLsxrOfd24VffwEvHUNpgiCq9Pq6+P2PAO0AnmZxtZt3nL/CbKH NHWPUc3iwqZJnVT0+EKbMIH8aINIrkfADkDZIxvC9AzXInn59ieBbipSN5uh0UxHSf EIHr/AQE5Soz6Llnzl5ujr9o/zUyrfKjSHr8dnRI= Date: Sat, 10 Oct 2026 14:40:02 -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: <20261010214002.706F51F00893@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: Sat, 03 Oct 2026 17:33:02 +0100 Rather than directly checking VMA flags, use the newly introduced vma_is_mm_managed() and vma_is_mm_backed() 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 mm-managed mappings may not set VMA_IO_BIT so the check is now redundant. Link: https://lore.kernel.org/20261003-b4-mmap-prepare-vma-flag-sanify-v4-31-a1f052500fd7@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton Acked-by: Zi Yan Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Jann Horn Cc: Pedro Falcato Cc: David Hildenbrand Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: Jonathan Corbet Cc: Greg Kroah-Hartman Cc: Dennis Dalessandro Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Paul Moore Cc: Stephen Smalley Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Andrii Nakryiko Cc: Eduard Zingerman Cc: Kumar Kartikeya Dwivedi Cc: Baolin Wang Cc: Nico Pache Cc: Ryan Roberts Cc: Dev Jain Cc: Barry Song Cc: Lance Yang Cc: Usama Arif Cc: Kiryl Shutsemau Cc: Doug Gilbert Cc: James Bottomley Cc: Martin K. Petersen Cc: Simona Vetter Cc: Helge Deller Cc: Sebastian Reichel Cc: John Hubbard Cc: Peter Xu Cc: Masami Hiramatsu Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Mark Rutland Cc: Rik van Riel Cc: Harry Yoo Cc: Juri Lelli Cc: Vincent Guittot Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Will Deacon Cc: Aneesh Kumar K.V Cc: Nicholas Piggin Cc: Arnd Bergmann Cc: Muchun Song Cc: Oscar Salvador Cc: Matthew Wilcox (Oracle) Cc: Jan Kara Cc: Marc Zyngier Cc: Oliver Upton Cc: Catalin Marinas Cc: Madhavan Srinivasan Cc: Anup Patel Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Christian Borntraeger Cc: Janosch Frank Cc: Claudio Imbrenda Cc: Alexander Gordeev Cc: Gerald Schaefer Cc: Heiko Carstens Cc: Vasily Gorbik Cc: David S. Miller Cc: Andreas Larsson Cc: Al Viro Cc: Christian Brauner Cc: Matthew Brost Cc: Joshua Hahn Cc: Rakie Kim Cc: Byungchul Park Cc: Gregory Price Cc: Ying Huang Cc: Alistair Popple Cc: Chris Li Cc: Kairui Song Cc: Kemeng Shi Cc: Nhat Pham Cc: Baoquan He Cc: Youngjun Park Cc: Johannes Weiner Cc: Qi Zheng Cc: Shakeel Butt Cc: Axel Rasmussen Cc: Yuanchu Xie Cc: Wei Xu Cc: Chengming Zhou Cc: Michal Hocko Cc: Miklos Szeredi Cc: Xu Xin --- mm/userfaultfd.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) --- a/mm/userfaultfd.c~mm-uffd-use-predicates-for-userfaultfd-checks +++ a/mm/userfaultfd.c @@ -1755,10 +1755,16 @@ 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 mappings not managed by core mm. */ + if (!vma_is_mm_managed(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. */ + return !vma_is_hugetlb(vma); } static int validate_move_areas(struct userfaultfd_ctx *ctx, @@ -2147,10 +2153,11 @@ 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)) + /* Only mm-backed memory can have its faults handled by userspace. */ + if (!vma_is_mm_backed(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-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-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 mm-vma-dont-remove-vma-from-rmap-if-pgoff-unchanged.patch