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 DF1793E40E8; Tue, 8 Sep 2026 20:14:21 +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=1788898463; cv=none; b=EZ9yKP/yaaaradlOZX6p0AkV/jCTyBlzboEGwr9Ps/jIm7U4jGu0vMdekMn1gguh7o56HIXylN7U35kJqND7qJNa6BRO9cnDldqv5Vc+50R40mjsTuHwN5oSlUc0YbjielJoW+9L1pnd0pwWyhH4RM4ki1w1jj26RonFfGWNdI4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788898463; c=relaxed/simple; bh=iIAFxQZLJ9bbMTZzaHnO7LS3UeZ6tj1UDBbYm6l6Gao=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=M6FDNEqdqBLayxH7eG/r47KKCE37eXUFrsyg1M1lcPnZKX2f5xnYCjU+EKwMVUs0o7NcnlptlT38ifu703RaJwyHNliahDkSG9K3Mfv6D7PiSZzRS4YH/xUr71yXIxhv8+rJv+lYzyY/T17eyY9RDJdj4O9LNilvWqv5iSSXLgU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S1m034QT; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S1m034QT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A1551F00A3A; Tue, 8 Sep 2026 20:13:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788898461; bh=6NnPPfuZme0NSkQHeWnz1PsLK7rAxCsSDuwDKuv1y3M=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=S1m034QTgk4AAbMXhW3pBtSw4QN0ohxWlW4RNkxcLFATJ1xhyGPLecmEi+XMI12qW dr3YRNGrou5rS/KM/JBBY7Bc1xloPttF8CkVagWQeY1UlWPXJ3NTTjLyPlp1X/u6Wl cyN3WIw1b4iT5LLwuNxVGKoC2gFM0jgLiEn9U+AOIloCIPUiM7dNbuAlEF1UqVXha8 /YhYT64ERxftJgX4JOAg85vFPR0pBt5g3kiBrJtaa60XXFr9UgVRnB6xUIajIqW4Jn uapeZWXKlMmQb3eCTGRlvsZs9Fwq6U74Qv7qPuz1OiS3EYPZnSyYwcvjVRz44fLnpx ySKehVRKCbJaA== From: "Lorenzo Stoakes (ARM)" Date: Tue, 08 Sep 2026 21:01:29 +0100 Subject: [PATCH 25/39] mm: remove VMA_IO_BIT check in vma[_flags]_is_kernel_owned() Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260908-b4-mmap-prepare-vma-flag-sanify-v1-25-dacf19cce22b@kernel.org> References: <20260908-b4-mmap-prepare-vma-flag-sanify-v1-0-dacf19cce22b@kernel.org> In-Reply-To: <20260908-b4-mmap-prepare-vma-flag-sanify-v1-0-dacf19cce22b@kernel.org> To: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , David Hildenbrand , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Greg Kroah-Hartman , Dennis Dalessandro , Jason Gunthorpe , Leon Romanovsky , Paul Moore , Stephen Smalley , Jaroslav Kysela , Takashi Iwai , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Doug Gilbert , "James E.J. Bottomley" , "Martin K. Petersen" , Jaya Kumar , Simona Vetter , Helge Deller , Sebastian Reichel , John Hubbard , Peter Xu , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Rik van Riel , Harry Yoo , Juri Lelli , Vincent Guittot , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Arnd Bergmann , Muchun Song , Oscar Salvador , "Matthew Wilcox (Oracle)" , Jan Kara , Marc Zyngier , Oliver Upton , Catalin Marinas , Madhavan Srinivasan , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , "David S. Miller" , Andreas Larsson , Alexander Viro , Christian Brauner , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Youngjun Park , Johannes Weiner , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Xu Xin , Chengming Zhou , Michal Hocko , Miklos Szeredi Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-rdma@vger.kernel.org, selinux@vger.kernel.org, linux-sound@vger.kernel.org, bpf@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, fuse-devel@lists.linux.dev, "Lorenzo Stoakes (ARM)" X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=6787; i=ljs@kernel.org; h=from:subject:message-id; bh=iIAFxQZLJ9bbMTZzaHnO7LS3UeZ6tj1UDBbYm6l6Gao=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLIWZG6J5gwLWxnw/3LWiiVr+5dyZGz0NBAoqlfUvdy3Z 0fQ3JblHaUsDGJcDLJiiizPv4jvDxIJm9d5wd8NZg4rE8gQBi5OAZhI7EZGhnXJ5W/ECr8k/b4+ by7fxG0/LGo+a1SpHzrh+dp3pQmPxjKGf/abVzT8+eotfOXdnKAjGZPfZU3dF9KQxu9xkbM7xNH ahwMA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 We have now made it such that every driver which sets VMA_IO_BIT marks it as kernel-owned. However, vma_flags_is_kernel_owned() currently checks for VMA_IO_BIT. This was a product of drivers previously marking a range as kernel-owned by setting VMA_IO_BIT alone. Fix this by removing the VMA_IO_BIT check in vma_flags_is_kernel_owned(), and update mmap_validate_vma_flags() to use vma_flags_is_kernel_owned() rather than open-coding the VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT check. This change means that vma[_flags]_can_merge() doesn't check VMA_IO_BIT any longer (which is now redundant) as it calls vma_flags_is_kernel_owned(). Now that the predicate means precisely VMA_PFNMAP_BIT or VMA_MIXEDMAP_BIT, also use it at the other sites which open-code that pair, so the intent is stated rather than the flags, with no functional change: zap_special_vma_range() only zaps kernel-owned mappings, as drivers use it to tear down ranges they established themselves. The mprotect() arch PFN modification check applies to kernel-owned mappings, which may map PFNs without struct pages. NUMA balancing skips VM_MIXEDMAP mappings having already excluded VM_IO and VM_PFNMAP mappings via vma_migratable(), so it skips exactly the kernel-owned mappings - say so. Finally, update the VMA userland merge 'special' flag tests to no longer assert that VMA_IO_BIT prevents merge as VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT now suffices. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 3 +-- kernel/sched/fair.c | 2 +- mm/memory.c | 6 +++--- mm/mprotect.c | 3 +-- mm/vma.c | 2 +- tools/testing/vma/include/dup.h | 3 +-- tools/testing/vma/tests/merge.c | 10 ++-------- 7 files changed, 10 insertions(+), 19 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index bca955941212..15fc4509784b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1630,8 +1630,7 @@ static inline bool vma_is_shared_maywrite(const struct vm_area_struct *vma) */ static inline bool vma_flags_is_kernel_owned(const vma_flags_t *flags) { - return vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT, - VMA_IO_BIT); + return vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT); } /** diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8dff37059faf..a71f0ab79bcd 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4212,7 +4212,7 @@ static void task_numa_work(struct callback_head *work) for (; vma; vma = vma_next(&vmi)) { if (!vma_migratable(vma) || !vma_policy_mof(vma) || - is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) { + is_vm_hugetlb_page(vma) || vma_is_kernel_owned(vma)) { trace_sched_skip_vma_numa(mm, vma, NUMAB_SKIP_UNSUITABLE); continue; } diff --git a/mm/memory.c b/mm/memory.c index 8c9675451d4b..28c1bb7b93af 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2343,19 +2343,19 @@ void zap_vma_range(struct vm_area_struct *vma, unsigned long address, } /** - * zap_special_vma_range - zap all page table entries in a special vma range + * zap_special_vma_range - zap all page table entries in a kernel-owned VMA * @vma: the vma covering the range to zap * @address: starting address of the range to zap * @size: number of bytes to zap * * This function does nothing when the provided address range is not fully - * contained in @vma, or when the @vma is not VM_PFNMAP or VM_MIXEDMAP. + * contained in @vma, or when @vma is not kernel-owned. */ void zap_special_vma_range(struct vm_area_struct *vma, unsigned long address, unsigned long size) { if (!range_in_vma(vma, address, address + size) || - !(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))) + !vma_is_kernel_owned(vma)) return; zap_vma_range(vma, address, size); diff --git a/mm/mprotect.c b/mm/mprotect.c index 2888ee638d87..fe32fd87cf5c 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -783,8 +783,7 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, * uncommon case, so doesn't need to be very optimized. */ if (arch_has_pfn_modify_check() && - vma_flags_test_any(&old_vma_flags, VMA_PFNMAP_BIT, - VMA_MIXEDMAP_BIT) && + vma_flags_is_kernel_owned(&old_vma_flags) && !vma_flags_test_any_mask(&new_vma_flags, VMA_ACCESS_FLAGS)) { pgprot_t new_pgprot = vm_get_page_prot(newflags); diff --git a/mm/vma.c b/mm/vma.c index 5996757d5aaf..eb2b4501a677 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2772,7 +2772,7 @@ static int mmap_validate_vma_flags(const vma_flags_t *flags) return -EINVAL; #endif - if (!vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT)) { + if (!vma_flags_is_kernel_owned(flags)) { /* Only kernel-owned mappings may set VMA_IO_BIT. */ if (WARN_ON_ONCE(vma_flags_test(flags, VMA_IO_BIT))) return -EINVAL; diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/dup.h index 3fe40e0f4034..e6cb2ea196f2 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -1661,8 +1661,7 @@ static inline bool file_is_dev_zero(const struct file *file) static inline bool vma_flags_is_kernel_owned(const vma_flags_t *flags) { - return vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT, - VMA_IO_BIT); + return vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT); } static inline bool vma_is_kernel_owned(const struct vm_area_struct *vma) diff --git a/tools/testing/vma/tests/merge.c b/tools/testing/vma/tests/merge.c index acaab282939c..b26f1a66a170 100644 --- a/tools/testing/vma/tests/merge.c +++ b/tools/testing/vma/tests/merge.c @@ -496,17 +496,11 @@ static bool test_vma_merge_special_flags(void) .mm = &mm, .vmi = &vmi, }; - vma_flag_t special_flags[] = { VMA_IO_BIT, VMA_DONTEXPAND_BIT, + vma_flag_t special_flags[] = { VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT }; - vma_flags_t all_special_flags = EMPTY_VMA_FLAGS; int i; struct vm_area_struct *vma_left, *vma; - /* Make sure there aren't new VM_SPECIAL flags. */ - for (i = 0; i < ARRAY_SIZE(special_flags); i++) - vma_flags_set(&all_special_flags, special_flags[i]); - ASSERT_FLAGS_SAME_MASK(&all_special_flags, VMA_SPECIAL_FLAGS); - /* * 01234 * AAA @@ -520,7 +514,7 @@ static bool test_vma_merge_special_flags(void) * 01234 * AAA* * - * This should merge if not for the VM_SPECIAL flag. + * This should merge if not for the 'special' flag. */ vmg_set_range(&vmg, 0x3000, 0x4000, 3, vma_flags); for (i = 0; i < ARRAY_SIZE(special_flags); i++) { -- 2.55.0