From nobody Fri Sep 25 09:21:17 2026 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 7DCD0483BE1; Mon, 14 Sep 2026 14:59:56 +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=1789397999; cv=none; b=cS5RbszWmoePuAk74yOF4fnqUGLlRGNbVs0hxAeq10SF1OmLjxMRw+SlQrxYL3ll397MqigR0kLS414P9UYkUsg8S7uzff/ZLamOH3i+6zzTXoHYYej2eTcJSnP7Rp9eR2OCkgdyrOvbl4IVSthB6oyKfhxnh/wBpxlvaGo5f+Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789397999; c=relaxed/simple; bh=4yp7BsZu3CgBi+wzXgbyuSQeObOnQL+E7WfwicYJ0TI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=OXaUCSOUOz5K+P3MNLzjVWkZeTt8cB1qCR696j3BkVkPW5Sk3jjnxtWY22kHIB9v6UyR3QkxQ/UbebgOUBREu3+72Q3az0ijF1bMr+5JphIjY+Ao6bEHSS9xnzgFtWPLdq3z6aQKP5NinPUNcPpQsDoqQ3My22lUr9rNaLLzCqE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dy5XhP6y; 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="dy5XhP6y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED0581F008A7; Mon, 14 Sep 2026 14:59:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789397996; bh=c7lvZWHF45BLk2nULsRrXMqDsfJN+uyHFP8jlbR2Auk=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=dy5XhP6y8dXr+8ojo8Ufl96AGLd+w5X33MUvMQ1VIg330J+1vzAlSodls0yVZL6h8 9umBQgb3yvjSm1pEmZ8yn0oRA/LpuCfPvl6eYFLDlRid/Cd874jeGc+7u+5fj3Cbxm 7f7XnF9tneW7HNNtIgEbhzAn//MPgU14hyENVLl8FQ5Xfk0a6FD8p2plNzHVNOcINA a36DQ3EipM9iXNSUvnkX86+FpWZ41OROfJwIPubaH69f3V9biVWy7fTE6Bu96RqQL4 Z528hSCG3Zm20Jel04/18h14CvzIO5VaKJ1Zv0qtOmkyR01DSWBhhJuhfmmq4V1OqX ppCQ2eX8biOfw== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:21 +0100 Subject: [PATCH v2 01/40] mm/vma: fix mmap_prepare file handling, remove file_doesnt_need_get Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-1-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=11359; i=ljs@kernel.org; h=from:subject:message-id; bh=4yp7BsZu3CgBi+wzXgbyuSQeObOnQL+E7WfwicYJ0TI=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK/131rk/Zsr6+iCmwahbGrHJpVE2lmszj3xcILbV M2zpuwvO0pZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjCRe1EM/3OOR08t3Tjpu/VV 6+5KBwa3xLyr+RU32ma4X/5zUW7a4ckM/9Qfx1esL9nY+yOa/XHvsvU39LaLpr+47jZ5/7eGIJE tNxkA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 The map->file_doesnt_need_get flag is confusing and the existing implementation has holes. Drivers are permitted to change the owning file of a mapping. If they do so, they are required to take a reference on that file. The mmap() operation which ultimately invokes __mmap_region() is guaranteed to drop the refcount for the original file the mapping was made under, but this is not true for the replaced file. This has been addressed so far by tracking map->file_doesnt_need_get, which is rather poorly named and unfortunately fails to correctly track whether or not an additional put were needed in a number of cases. Make life easier by removing this flag, and instead drop the reference for both mmap_prepare and the deprecated mmap callback in a new function put_map(). Track whether this needs to be done by aligning mmap_state with vm_area_desc and store the original file in the map->file field, keeping the updated file in map->vm_file. In order to have the same behaviour for both types of hooks, only drop the reference __mmap_new_file_vma() itself took in its error path, deferring the replaced file's reference to put_map(). To make this work correctly, map->vm_file has to be updated before any error handling, so update __mmap_new_file_vma() and call_mmap_prepare() to set this field first. Also when mmap_prepare() changes the file and is then merged, the reference count also must be decremented, so update the logic to call put_map() in this case too. Also update __compat_vma_mmap() to manually perform this step for stacked file systems using the compatibility layer, and update compat_set_vma_from_desc() to replace vma_set_file() with a correct refcount/file update. No in-tree driver is impacted by the incorrect implementation of this currently (no driver that does this is mergeable for one), so this does not need to be a fix. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/internal.h | 1 + mm/util.c | 5 +++- mm/vma.c | 95 ++++++++++++++++++++++++++++++++++---------------------= ---- mm/vma.h | 6 ++-- 4 files changed, 64 insertions(+), 43 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index 0dca33db068f..fe576d468af4 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -7,6 +7,7 @@ #ifndef __MM_INTERNAL_H #define __MM_INTERNAL_H =20 +#include #include #include #include diff --git a/mm/util.c b/mm/util.c index bf0513d1d3d0..016932780925 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1228,8 +1228,11 @@ int __compat_vma_mmap(struct vm_area_desc *desc, =20 /* Perform any preparatory tasks for mmap action. */ err =3D mmap_action_prepare(desc); - if (err) + if (err) { + if (desc->vm_file !=3D vma->vm_file) + fput(desc->vm_file); return err; + } /* Update the VMA from the descriptor. */ compat_set_vma_from_desc(vma, desc); /* Complete any specified mmap actions. */ diff --git a/mm/vma.c b/mm/vma.c index 55917d097933..a319a9fc2f29 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -24,7 +24,8 @@ struct mmap_state { vm_flags_t vm_flags; vma_flags_t vma_flags; }; - struct file *file; + struct file *file; /* mmap()-specified file. */ + struct file *vm_file; /* May be updated by mmap_prepare. */ pgprot_t page_prot; =20 /* User-defined fields, perhaps updated by .mmap_prepare(). */ @@ -43,8 +44,6 @@ struct mmap_state { =20 /* Determine if we can check KSM flags early in mmap() logic. */ bool check_ksm_early :1; - /* If .mmap_prepare changed the file, we don't need to pin. */ - bool file_doesnt_need_get :1; }; =20 #define MMAP_STATE(name, mm_, vmi_, addr_, len_, pgoff_, anon_pgoff_, vma_= flags_, file_) \ @@ -58,6 +57,7 @@ struct mmap_state { .pglen =3D PHYS_PFN(len_), \ .vma_flags =3D vma_flags_, \ .file =3D file_, \ + .vm_file =3D file_, \ .page_prot =3D vma_flags_to_page_prot(vma_flags_), \ } =20 @@ -70,7 +70,7 @@ struct mmap_state { .vma_flags =3D (map_)->vma_flags, \ .pgoff =3D (map_)->pgoff, \ .anon_pgoff =3D (map_)->anon_pgoff, \ - .file =3D (map_)->file, \ + .file =3D (map_)->vm_file, \ .prev =3D (map_)->prev, \ .middle =3D vma_, \ .next =3D (vma_) ? NULL : (map_)->next, \ @@ -2447,7 +2447,7 @@ void mm_drop_all_locks(struct mm_struct *mm) */ static bool accountable_mapping(struct mmap_state *map) { - const struct file *file =3D map->file; + const struct file *file =3D map->vm_file; =20 /* * hugetlb has its own accounting separate from the core VM @@ -2496,7 +2496,7 @@ static void vms_abort_munmap_vmas(struct vma_munmap_s= truct *vms, =20 static void update_ksm_flags(struct mmap_state *map) { - map->vma_flags =3D ksm_vma_flags(map->mm, map->file, map->vma_flags); + map->vma_flags =3D ksm_vma_flags(map->mm, map->vm_file, map->vma_flags); } =20 static void set_desc_from_map(struct vm_area_desc *desc, @@ -2506,7 +2506,7 @@ static void set_desc_from_map(struct vm_area_desc *de= sc, desc->end =3D map->end; =20 desc->pgoff =3D map->pgoff; - desc->vm_file =3D map->file; + desc->vm_file =3D map->vm_file; desc->vma_flags =3D map->vma_flags; desc->page_prot =3D map->page_prot; } @@ -2586,6 +2586,10 @@ static int __mmap_setup(struct mmap_state *map, stru= ct vm_area_desc *desc, return 0; } =20 +static bool map_same_file(struct mmap_state *map) +{ + return map->vm_file =3D=3D map->file; +} =20 static int __mmap_new_file_vma(struct mmap_state *map, struct vm_area_struct *vma) @@ -2593,20 +2597,23 @@ static int __mmap_new_file_vma(struct mmap_state *m= ap, struct vma_iterator *vmi =3D map->vmi; int error; =20 - vma->vm_file =3D map->file; - if (!map->file_doesnt_need_get) - get_file(map->file); + vma->vm_file =3D map->vm_file; + if (map_same_file(map)) + get_file(map->vm_file); =20 - if (!map->file->f_op->mmap) + if (!map->vm_file->f_op->mmap) return 0; =20 error =3D mmap_file(vma->vm_file, vma); + map->vm_file =3D vma->vm_file; + if (error) { UNMAP_STATE(unmap, vmi, vma, vma->vm_start, vma->vm_end, map->prev, map->next); - fput(vma->vm_file); - vma->vm_file =3D NULL; + if (map_same_file(map)) + fput(map->vm_file); =20 + vma->vm_file =3D NULL; vma_iter_set(vmi, vma->vm_end); /* Undo any partial mapping done by a device driver. */ unmap_region(&unmap); @@ -2623,7 +2630,6 @@ static int __mmap_new_file_vma(struct mmap_state *map, !vma_flags_test(&map->vma_flags, VMA_MAYWRITE_BIT) && vma_test(vma, VMA_MAYWRITE_BIT)); =20 - map->file =3D vma->vm_file; map->vma_flags =3D vma->flags; =20 return 0; @@ -2631,7 +2637,7 @@ static int __mmap_new_file_vma(struct mmap_state *map, =20 static void map_set_anon(struct mmap_state *map) { - map->file =3D NULL; + map->vm_file =3D NULL; map->vm_ops =3D NULL; map->pgoff =3D map->addr >> PAGE_SHIFT; } @@ -2643,7 +2649,7 @@ static bool map_is_private(const struct mmap_state *m= ap) =20 static bool map_is_anon(const struct mmap_state *map) { - return map_is_private(map) && !map->file; + return map_is_private(map) && !map->vm_file; } =20 /* @@ -2688,7 +2694,7 @@ static int __mmap_new_vma(struct mmap_state *map, str= uct vm_area_struct **vmap, } =20 /* Invoke callbacks. */ - if (map->file) + if (map->vm_file) error =3D __mmap_new_file_vma(map, vma); else if (!is_anon) error =3D shmem_zero_setup(vma); @@ -2797,36 +2803,34 @@ static int call_mmap_prepare(struct mmap_state *map, int err; =20 /* Invoke the hook. */ - err =3D vfs_mmap_prepare(map->file, desc); - if (err) - return err; - - /* It's invalid for mmap_preprare hooks to clear vm_ops. */ - if (!desc->vm_ops) - return -EINVAL; - - err =3D call_action_prepare(map, desc); + err =3D vfs_mmap_prepare(map->vm_file, desc); if (err) return err; =20 /* Update fields permitted to be changed. */ map->pgoff =3D desc->pgoff; - if (desc->vm_file !=3D map->file) { - map->file_doesnt_need_get =3D true; - map->file =3D desc->vm_file; - } + if (desc->vm_file !=3D map->vm_file) + map->vm_file =3D desc->vm_file; map->vma_flags =3D desc->vma_flags; map->page_prot =3D desc->page_prot; /* User-defined fields. */ map->vm_ops =3D desc->vm_ops; map->vm_private_data =3D desc->private_data; =20 + /* It's invalid for mmap_prepare hooks to clear vm_ops. */ + if (!desc->vm_ops) + return -EINVAL; + + err =3D call_action_prepare(map, desc); + if (err) + return err; + /* * MAP_PRIVATE-/dev/zero mappings are an ancient way of getting * anonymous mappings. Rather than allowing these mappings to be odd * outliers, simply make them truly anonymous. */ - if (map_is_private(map) && file_is_dev_zero(map->file)) + if (map_is_private(map) && file_is_dev_zero(map->vm_file)) map_set_anon(map); =20 return 0; @@ -2845,7 +2849,7 @@ static void set_vma_user_defined_fields(struct vm_are= a_struct *vma, */ static bool can_set_ksm_flags_early(struct mmap_state *map) { - struct file *file =3D map->file; + struct file *file =3D map->vm_file; =20 /* Anonymous mappings have no driver which can change them. */ if (!file) @@ -2868,6 +2872,20 @@ static bool can_set_ksm_flags_early(struct mmap_stat= e *map) return false; } =20 +static void put_map(struct mmap_state *map) +{ + /* + * An error occurred or the VMA was merged. + * + * If the file was changed by the driver (which is required to increment + * the replacement file's reference count), drop its reference count. + * + * On error, the caller always drops the original file regardless. + */ + if (map->vm_file && !map_same_file(map)) + fput(map->vm_file); +} + static unsigned long __mmap_region(struct file *file, unsigned long addr, unsigned long len, vma_flags_t vma_flags, unsigned long pgoff, struct list_head *uf) @@ -2922,7 +2940,10 @@ static unsigned long __mmap_region(struct file *file= , unsigned long addr, =20 __mmap_complete(&map, vma); =20 - if (have_mmap_prepare && allocated_new) { + if (!allocated_new) { + /* Merged, so need to drop refcount. */ + put_map(&map); + } else if (have_mmap_prepare) { error =3D mmap_action_complete(vma, &desc.action, /*is_compat=3D*/false); if (error) @@ -2936,13 +2957,7 @@ static unsigned long __mmap_region(struct file *file= , unsigned long addr, if (map.charged) vm_unacct_memory(map.charged); abort_munmap: - /* - * This indicates that .mmap_prepare has set a new file, differing from - * desc->vm_file. But since we're aborting the operation, only the - * original file will be cleaned up. Ensure we clean up both. - */ - if (map.file_doesnt_need_get) - fput(map.file); + put_map(&map); vms_abort_munmap_vmas(&map.vms, &map.mas_detach); return error; } diff --git a/mm/vma.h b/mm/vma.h index e97bd2dfa786..f15faa83f3d6 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -394,8 +394,10 @@ static inline void compat_set_vma_from_desc(struct vm_= area_struct *vma, =20 /* Mutable fields. Populated with initial state. */ vma_set_pgoff(vma, desc->pgoff); - if (desc->vm_file !=3D vma->vm_file) - vma_set_file(vma, desc->vm_file); + if (desc->vm_file !=3D vma->vm_file) { + fput(vma->vm_file); + vma->vm_file =3D desc->vm_file; + } vma->flags =3D desc->vma_flags; vma->vm_page_prot =3D desc->page_prot; =20 --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 D08FD483BED; Mon, 14 Sep 2026 15:00:24 +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=1789398026; cv=none; b=kg4Eq3JUgkMvn3wHC74hAvibYgn5Ju1qG2GUdQvFASXORFsFd04zU7iZfu2vuS5ADi3mB9nTw9uN6AEbulk6B7HJSNUMgqRwSPCgTWZBfMIZPjYoDmQD0AOt3lMFy5NCXQeO4hGV6YrbHr2UnwhdB/bjAwvUBcyzfGuawXt7yzA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398026; c=relaxed/simple; bh=UFrVRLvfvmL7sB7G5odMQ/5YgrxZlazK/5+N6FdQKJI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=owTUnhJmZDEy8zUeivAdrxWogpM5lktKB/BVW7+a1tR8i7l/SK0o90mV3feRKeZBGmenvWG9wlxQzJVs8Mo2T7VJfu8BMEc3tX+QUoyxxSr8vuiOvKFrBjGECj9EEkLMcIb2ppzGI5AzLPpXAgw1FXU6QKTfMrwN/RgZuwq04TQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dg2Fe5DA; 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="dg2Fe5DA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 751251F00893; Mon, 14 Sep 2026 14:59:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398024; bh=r1G+xFXCQNVBF8wxMQxvWMHZYPsF0so/uZjMXa7bsyg=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=dg2Fe5DAsf6cgSnFAtqKyclWLIYcQDBRezlkLWBcpnByHIDcZeYX1ozgrOmMphJP/ VIYfYlEL34LjVlmE0u9d55V0O+Mprf3eoWuZJRt8M1uKntD6yXAmC7zM3P6IqpE3xx 2Ov9QmoID5RyN3+5U5MaSJV2Nn867bU50b2moHPwXMaGK1k1CE+ZSHBRrc1xUY6bj0 qLwdNI3DP2/EjP/nsa9rxNfzOvxVTH4iaP37WYXwkICznAVOxz1wsvoq3Hk6aRF/Mn N9xg2+rHHkWqvIyhlFPeawYni8ydfuf7wItDpyMV5A3ltZ9Wgnp+NId197Rc10bBAD KH3DZtVDniryQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:22 +0100 Subject: [PATCH v2 02/40] mm/vma: predicate setting mmap_prepare VMA fields on new vma alloc Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-2-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=1712; i=ljs@kernel.org; h=from:subject:message-id; bh=UFrVRLvfvmL7sB7G5odMQ/5YgrxZlazK/5+N6FdQKJI=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK89H34+9rDukTPlXlUr9mobCb2evH31Oq6GVWeuK SfJfrj5u6OUhUGMi0FWTJHl+Rfx/UEiYfM6L/i7wcxhZQIZwsDFKQAT0TrHyDBDbMXH3D098s27 zgjc7/XoKWxPfnGaXUNR+5lwt6iF3FNGhie1c54s+xB6nWfStIkPbh83S7ihqrxvBf+zyefq36X lrWUCAA== X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 It only makes sense to manipulate VMA fields if we allocated a new VMA, rather than merged it. VMA merging does not compare vm_ops or vm_private_data, so a merged VMA keeps its own, which is also what the legacy f_op->mmap path does since it never touches an existing VMA. Previously set_vma_user_defined_fields() overwrote the merged VMA's fields with those set for the new mapping. In practice these are the same values, with rare exceptions such as shmem selecting vm_ops based on whether the file has been unlinked, so no user-visible change is expected. Make this dependency explicit, and additionally constify have_mmap_prepare while we're here. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/vma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/vma.c b/mm/vma.c index a319a9fc2f29..cd9e2113f66e 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2892,7 +2892,7 @@ static unsigned long __mmap_region(struct file *file,= unsigned long addr, { struct mm_struct *mm =3D current->mm; struct vm_area_struct *vma =3D NULL; - bool have_mmap_prepare =3D file && file->f_op->mmap_prepare; + const bool have_mmap_prepare =3D file && file->f_op->mmap_prepare; VMA_ITERATOR(vmi, mm, addr); const pgoff_t anon_pgoff =3D addr >> PAGE_SHIFT; MMAP_STATE(map, mm, &vmi, addr, len, pgoff, anon_pgoff, vma_flags, file); @@ -2935,7 +2935,7 @@ static unsigned long __mmap_region(struct file *file,= unsigned long addr, allocated_new =3D true; } =20 - if (have_mmap_prepare && !map_is_anon(&map)) + if (have_mmap_prepare && allocated_new && !map_is_anon(&map)) set_vma_user_defined_fields(vma, &map); =20 __mmap_complete(&map, vma); --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 71E4748C3FF; Mon, 14 Sep 2026 15:00:52 +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=1789398054; cv=none; b=isPtkRE/MWCwoXuWklmMYNpNOVB81ZaHqZibgmJI6Dq28hllk6XZQHJe3JAXniJL3YnmMGBne28Hwz67qdu6qMddXY+ZRNttCPspbA6LxJ9IZN9lElE85J9RUkAJgEXYOPNxCRzkx4z65YG2B+bBK6z81jW+zzHSOh96IMr/hn8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398054; c=relaxed/simple; bh=UeK+5t/ISBUMaOH/QNariNr0UAqFlz1uaZ8lVxwqw7Y=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lSwkEMlHUPw/zxl74v4qQAmaL6Hi75bR9nIKQ9kWajSGjg885eY+R6OoZFHEMSql8iUaEHdYpfmW8WIOJSkH7RtdyDG0p40Hgff1XFz2J3u+XQRyredS4Wc/h1mpOZI7fbisRdGuqEZxEOHuD2xEzQK+/t7f8hLSPOEE7rNVluE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=k272WiCM; 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="k272WiCM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E52371F0089A; Mon, 14 Sep 2026 15:00:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398052; bh=jnM1GsA9H7o34yRQ0eF8yQwW9qODITMQHOHlTqLrEwM=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=k272WiCMeVOfTkjgsOqSHrR31bdHuIqZE54YmIPsbFx5Lx/nW//2GH57VtUdD4fve adrIqrmI5y67hBOGluixAZPziSWHUplLSC6UWi115hWJ8HdBDWhAe1+IbDYiylRGVn BGt6aSapXEhEkVSG79TOAJ+exXex/fBQZnhXNNF2qeKqpxQUBv1v7yUKBhqj0pmOG0 rsula901YG9tlVDqA0mdJh+Qq8Ywrorkk96/AHMUH7JjBarDHCQ5NiBYTOvmAqKiJK bKg/4M3qVN/mIrycokuPxEdxH4as74ZBgJgc2/+SB6m71zuMTrikybxAGEZqe+i5ry Bt5RSoCnf1LSQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:23 +0100 Subject: [PATCH v2 03/40] mm/vma: introduce and use vma_[flags_]can_merge() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-3-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=3665; i=ljs@kernel.org; h=from:subject:message-id; bh=UeK+5t/ISBUMaOH/QNariNr0UAqFlz1uaZ8lVxwqw7Y=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK8rmnjvysq/xZz/+RgK648+Wnfy3/Mrv2dVH1nRt M7xn9jkZx2lLAxiXAyyYoosz7+I7w8SCZvXecHfDWYOKxPIEAYuTgGYSHkWI8ONtK/6N85texQy R7EirenuOb/Tsyazvahvbf4/c+uHuuJqhv+VNpv+O7TGcdxJVQntMpa8NPkBx3r15w//TjFZfT8 5NIARAA== X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Replace the open-coded VMA_SPECIAL_FLAGS check in the VMA merge logic with two new functions vma_flags_can_merge() and vma_can_merge() and update the merge logic to use the former. This abstracts the check and expresses it in terms of the desired behaviour rather than an arbitrary and confusing VMA flag. This also lays the groundwork for making further improvements in VMA flag usage. Also update the userland VMA tests to reflect the change. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 21 +++++++++++++++++++++ mm/vma.c | 19 +++++++++++-------- tools/testing/vma/include/dup.h | 5 +++++ 3 files changed, 37 insertions(+), 8 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 969594074fd2..68250ece4219 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1612,6 +1612,27 @@ static inline bool vma_is_shared_maywrite(const stru= ct vm_area_struct *vma) return is_shared_maywrite(&vma->flags); } =20 +/** + * vma_flags_can_merge() - Do the specified VMA flags permit the VMA to be + * merged with another? + * @flags: The VMA flags to test. + * Returns: true if the flags permit merging, false otherwise. + */ +static inline bool vma_flags_can_merge(const vma_flags_t *flags) +{ + return !vma_flags_test_any_mask(flags, VMA_SPECIAL_FLAGS); +} + +/** + * vma_can_merge() - Do @vma's flags permit it to be merged with another V= MA? + * @vma: The VMA to test. + * Returns: true if the flags permit merging, otherwise false. + */ +static inline bool vma_can_merge(const struct vm_area_struct *vma) +{ + return vma_flags_can_merge(&vma->flags); +} + /** * vma_kernel_pagesize - Default page size granularity for this VMA. * @vma: The user mapping. diff --git a/mm/vma.c b/mm/vma.c index cd9e2113f66e..dc74b3d721cc 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -924,13 +924,14 @@ static __must_check struct vm_area_struct *vma_merge_= existing_range( =20 vmg->state =3D VMA_MERGE_NOMERGE; =20 + if (!vma_flags_can_merge(&vmg->vma_flags)) + return NULL; /* - * If a special mapping or if the range being modified is neither at the - * furthermost left or right side of the VMA, then we have no chance of - * merging and should abort. + * If the range being modified is neither at the furthermost left or + * right side of the VMA, then we have no chance of merging and should + * abort. */ - if (vma_flags_test_any_mask(&vmg->vma_flags, VMA_SPECIAL_FLAGS) || - (!left_side && !right_side)) + if (!left_side && !right_side) return NULL; =20 if (left_side) @@ -1152,9 +1153,11 @@ struct vm_area_struct *vma_merge_new_range(struct vm= a_merge_struct *vmg) =20 vmg->state =3D VMA_MERGE_NOMERGE; =20 - /* Special VMAs are unmergeable, also if no prev/next. */ - if (vma_flags_test_any_mask(&vmg->vma_flags, VMA_SPECIAL_FLAGS) || - (!prev && !next)) + if (!vma_flags_can_merge(&vmg->vma_flags)) + return NULL; + + /* VMAs with no prev/next are unmergeable. */ + if (!prev && !next) return NULL; =20 can_merge_left =3D can_vma_merge_left(vmg); diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/du= p.h index 16c09dac59d9..2fd422789717 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -1647,3 +1647,8 @@ static inline bool file_is_dev_zero(const struct file= *file) { return file && file->f_op =3D=3D &zero_fops; } + +static inline bool vma_flags_can_merge(const vma_flags_t *flags) +{ + return !vma_flags_test_any_mask(flags, VMA_SPECIAL_FLAGS); +} --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 EE448481FD0; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kDawSCi4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 773501F00893; Mon, 14 Sep 2026 15:00:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398079; bh=8ilZPof+0LbvqXcFOGPThHadpzY2562CA+jmNtEIktM=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=kDawSCi4DhKj/pYuYizEVxBuLMYZVZkf/PMHi3bfT7mAk54RFcQjk5ooCqgLP89B/ pv8WibAs2fQYov93eA+ovjx/XmpJM7HsArl+H7sDGG+vSYHIA3ckyWbRjqJqtZEupq WikqKE3LrUm61hLTs3KYTt4fMxR9IPuOIqRvnCEJq4VfGSC0oS9DvCOH/Ib6uR9hIi +lajvJpzKP1DEgxpprmhs0Wt0QxMFWD+MRBKUzRKMqfwhWMolP9/cQmYuUxm/BR518 sRcssmWxlQHmV5Wi2yaQrQTLjWcQfNJQEmJatvgQPfJ+afyfk+DbaPIzuvs973CHjW SphVJxFe2DN1w== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:24 +0100 Subject: [PATCH v2 04/40] mm: consistently validate VMA state after mmap[_prepare] hooks Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-4-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=12664; i=ljs@kernel.org; h=from:subject:message-id; bh=mxXTL8qsj7rlH8qSs/uTdWkUxg3gik0quNO5GcgMUeU=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK+zFAt0VpG5Fn3c3E7j2fE9wTk2UuvCpcT+1p5iL JiZsPVZRykLgxgXg6yYIsvzL+L7g0TC5nVe8HeDmcPKBDKEgYtTACYiqsbIsOO6n/2WO16Wa560 bQs+vOlYlHrsQ/7OxlWXDiVyb3cv2M7wV/bWz2PHi3b3/7pffPTZfr8WWyn/M2d3dPHG90h3sU6 R5wAA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 When the f_op->mmap_prepare or deprecated f_op->mmap hooks are invoked, the driver might have done something crazy that is not permitted by the kernel. Currently we check for three such cases in __mmap_new_file_vma(), but only if the legacy f_op->mmap hook is used: * Did sparc ADI result in invalid flags? * Did the driver alter vma->vm_start? * Did the driver make a file-backed mapping on a read-only file writable? Generalise these checks for both mmap_prepare and mmap and apply to all invocations of mmap_file(), the f_op->mmap and f_op->mmap_prepare handling in the core VMA code and the mmap_prepare compatibility layer. We also WARN_ON_ONCE() on these conditions as they are things that should simply not occur in the kernel and it's important to call it out when it does. We invoke mmap_prepare_validate() after mmap_action_prepare(), as mmap actions often manipulate state in the descriptor thus providing the final state the VMA will be derived from. Also call mmap_validate_vma_flags() in insert_vm_struct() to ensure that special regions which are inserted (such as a VDSO or VVAR) also satisfy the sanity checks. This way every VMA established through an mmap hook, whether via mmap() or the compatibility layer, or inserted via insert_vm_struct(), has been validated. brk() VMAs never pass through a driver hook and so need no such check. While we're here, also fixup a couple disjoint blocks of #ifdef CONFIG_MMU. Finally, update the VMA userland tests to reflect the change. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/internal.h | 49 +++++++++++++-------- mm/util.c | 19 +++++--- mm/vma.c | 96 ++++++++++++++++++++++++++++++++++---= ---- mm/vma.h | 24 +++++++++-- tools/testing/vma/include/dup.h | 10 +++++ 5 files changed, 156 insertions(+), 42 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index fe576d468af4..1ed11eaf276a 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -213,6 +213,24 @@ static inline void *folio_raw_mapping(const struct fol= io *folio) return (void *)(mapping & ~FOLIO_MAPPING_FLAGS); } =20 +/* + * If the VMA has a close hook then close it, and since closing it might l= eave + * it in an inconsistent state which makes the use of any hooks suspect, c= lear + * them down by installing dummy empty hooks. + */ +static inline void vma_close(struct vm_area_struct *vma) +{ + if (vma->vm_ops && vma->vm_ops->close) { + vma->vm_ops->close(vma); + + /* + * The mapping is in an inconsistent state, and no further hooks + * may be invoked upon it. + */ + vma->vm_ops =3D &vma_dummy_vm_ops; + } +} + /* * This is a file-backed mapping, and is about to be memory mapped - invok= e its * mmap hook and safely handle error conditions. On error, VMA hooks will = be @@ -225,8 +243,11 @@ static inline void *folio_raw_mapping(const struct fol= io *folio) */ static inline int mmap_file(struct file *file, struct vm_area_struct *vma) { - int err =3D vfs_mmap(file, vma); + const unsigned long prev_start =3D vma->vm_start; + const vma_flags_t prev_flags =3D vma->flags; + int err; =20 + err =3D vfs_mmap(file, vma); /* * Either we tried to call the file hook for mmap() and an error arose * or a driver set vma->vm_ops =3D NULL intending there to be no VMA @@ -239,26 +260,16 @@ static inline int mmap_file(struct file *file, struct= vm_area_struct *vma) */ if (unlikely(err || !vma->vm_ops)) vma->vm_ops =3D &vma_dummy_vm_ops; + if (unlikely(err)) + return err; =20 - return err; -} - -/* - * If the VMA has a close hook then close it, and since closing it might l= eave - * it in an inconsistent state which makes the use of any hooks suspect, c= lear - * them down by installing dummy empty hooks. - */ -static inline void vma_close(struct vm_area_struct *vma) -{ - if (vma->vm_ops && vma->vm_ops->close) { - vma->vm_ops->close(vma); - - /* - * The mapping is in an inconsistent state, and no further hooks - * may be invoked upon it. - */ - vma->vm_ops =3D &vma_dummy_vm_ops; + err =3D mmap_hook_validate(prev_start, &prev_flags, vma); + if (unlikely(err)) { + vma->vm_start =3D prev_start; + vma_close(vma); } + + return err; } =20 /* unmap_vmas is in mm/memory.c */ diff --git a/mm/util.c b/mm/util.c index 016932780925..bdd5923eebc7 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1224,19 +1224,28 @@ EXPORT_SYMBOL(compat_set_desc_from_vma); int __compat_vma_mmap(struct vm_area_desc *desc, struct vm_area_struct *vma) { + struct vm_area_desc prev_desc; int err; =20 + /* Derive state prior to mmap_prepare hook. */ + compat_set_desc_from_vma(&prev_desc, desc->file, vma); /* Perform any preparatory tasks for mmap action. */ err =3D mmap_action_prepare(desc); - if (err) { - if (desc->vm_file !=3D vma->vm_file) - fput(desc->vm_file); - return err; - } + if (err) + goto err_put; + /* Check the caller did nothing crazy. */ + err =3D mmap_prepare_validate(&prev_desc, desc); + if (err) + goto err_put; /* Update the VMA from the descriptor. */ compat_set_vma_from_desc(vma, desc); /* Complete any specified mmap actions. */ return mmap_action_complete(vma, &desc->action, /*is_compat=3D*/true); + +err_put: + if (desc->vm_file !=3D vma->vm_file) + fput(desc->vm_file); + return err; } EXPORT_SYMBOL(__compat_vma_mmap); =20 diff --git a/mm/vma.c b/mm/vma.c index dc74b3d721cc..626a18c08a26 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2623,16 +2623,6 @@ static int __mmap_new_file_vma(struct mmap_state *ma= p, return error; } =20 - /* Drivers cannot alter the address of the VMA. */ - WARN_ON_ONCE(map->addr !=3D vma->vm_start); - /* - * Drivers should not permit writability when previously it was - * disallowed. - */ - VM_WARN_ON_ONCE(!vma_flags_same_pair(&map->vma_flags, &vma->flags) && - !vma_flags_test(&map->vma_flags, VMA_MAYWRITE_BIT) && - vma_test(vma, VMA_MAYWRITE_BIT)); - map->vma_flags =3D vma->flags; =20 return 0; @@ -2710,11 +2700,6 @@ static int __mmap_new_vma(struct mmap_state *map, st= ruct vm_area_struct **vmap, vma->flags =3D map->vma_flags; } =20 -#ifdef CONFIG_SPARC64 - /* TODO: Fix SPARC ADI! */ - WARN_ON_ONCE(!arch_validate_flags(map->vm_flags)); -#endif - /* Lock the VMA since it is modified after insertion into VMA tree */ vma_start_write(vma); vma_iter_store_new(vmi, vma); @@ -2777,6 +2762,76 @@ static void __mmap_complete(struct mmap_state *map, = struct vm_area_struct *vma) vma_set_page_prot(vma); } =20 +/* Check to ensure that the VMA flags of a newly mapped VMA are sane. */ +static int mmap_validate_vma_flags(const vma_flags_t *flags) +{ +#ifdef CONFIG_SPARC64 + const vm_flags_t legacy_flags =3D vma_flags_to_legacy(*flags); + + /* TODO: Fix SPARC ADI! */ + if (WARN_ON_ONCE(!arch_validate_flags(legacy_flags))) + return -EINVAL; +#endif + + return 0; +} + +/* Check to ensure a driver hasn't done something crazy. */ +static int mmap_validate(unsigned long prev_start, + unsigned long curr_start, + const vma_flags_t *prev_flags, + const vma_flags_t *curr_flags) +{ + bool was_maywrite, is_maywrite; + + /* Drivers cannot alter the address of the VMA. */ + if (WARN_ON_ONCE(prev_start !=3D curr_start)) + return -EINVAL; + + was_maywrite =3D vma_flags_test(prev_flags, VMA_MAYWRITE_BIT); + is_maywrite =3D vma_flags_test(curr_flags, VMA_MAYWRITE_BIT); + + /* A driver may not make a previously unwritable mapping writable. */ + if (WARN_ON_ONCE(!was_maywrite && is_maywrite)) + return -EINVAL; + + return mmap_validate_vma_flags(curr_flags); +} + +/** + * mmap_prepare_validate() - Ensure the driver hasn't violated invariants = in its + * f_op->mmap_prepare hook. + * @prev_desc: The VMA descriptor prior to the mmap_prepare hook being cal= led. + * @desc: The VMA descriptor after the mmap_prepare hook has been called. + * + * Returns: 0 on success, otherwise an error. + */ +int mmap_prepare_validate(const struct vm_area_desc *prev_desc, + const struct vm_area_desc *desc) +{ + return mmap_validate(prev_desc->start, desc->start, + &prev_desc->vma_flags, &desc->vma_flags); +} + +/** + * mmap_hook_validate() - Ensure the driver hasn't violated invariants in + * its f_op->mmap hook. + * @prev_start: The start of the mapping prior to the mmap hook. + * @prev_flags: The VMA flags set for the VMA prior to the mmap hook. + * @vma: The VMA after the hook has been applied. + * + * Returns: 0 on success, otherwise an error. + */ +int mmap_hook_validate(unsigned long prev_start, + const vma_flags_t *prev_flags, + const struct vm_area_struct *vma) +{ + const unsigned long start =3D vma->vm_start; + const vma_flags_t *flags =3D &vma->flags; + + return mmap_validate(prev_start, start, prev_flags, flags); +} + static int call_action_prepare(struct mmap_state *map, struct vm_area_desc *desc) { @@ -2803,6 +2858,7 @@ static int call_action_prepare(struct mmap_state *map, static int call_mmap_prepare(struct mmap_state *map, struct vm_area_desc *desc) { + const struct vm_area_desc prev_desc =3D *desc; int err; =20 /* Invoke the hook. */ @@ -2828,6 +2884,11 @@ static int call_mmap_prepare(struct mmap_state *map, if (err) return err; =20 + /* Check the caller did nothing crazy. */ + err =3D mmap_prepare_validate(&prev_desc, desc); + if (err) + return err; + /* * MAP_PRIVATE-/dev/zero mappings are an ancient way of getting * anonymous mappings. Rather than allowing these mappings to be odd @@ -3455,10 +3516,15 @@ int __vm_munmap(unsigned long start, size_t len, bo= ol unlock) int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) { unsigned long charged =3D vma_pages(vma); + int err; =20 if (find_vma_intersection(mm, vma->vm_start, vma->vm_end)) return -ENOMEM; =20 + err =3D mmap_validate_vma_flags(&vma->flags); + if (err) + return err; + if (vma_test(vma, VMA_ACCOUNT_BIT) && security_vm_enough_memory_mm(mm, charged)) return -ENOMEM; diff --git a/mm/vma.h b/mm/vma.h index f15faa83f3d6..77d395b8b103 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -782,14 +782,19 @@ struct vm_area_struct *vm_area_alloc(struct mm_struct= *mm); struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig); void vm_area_free(struct vm_area_struct *vma); =20 -/* vma_exec.c */ #ifdef CONFIG_MMU +int mmap_prepare_validate(const struct vm_area_desc *prev_desc, + const struct vm_area_desc *desc); + +int mmap_hook_validate(unsigned long prev_start, + const vma_flags_t *prev_flags, + const struct vm_area_struct *vma); + +/* vma_exec.c */ int create_init_stack_vma(struct mm_struct *mm, struct vm_area_struct **vm= ap, unsigned long *top_mem_p); int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift); -#endif =20 -#ifdef CONFIG_MMU /* * Denies creating a writable executable mapping or gaining executable per= missions. * @@ -838,6 +843,19 @@ static inline bool map_deny_write_exec(const vma_flags= _t *old, =20 return false; } +#else +static inline int mmap_prepare_validate(const struct vm_area_desc *prev_de= sc, + const struct vm_area_desc *desc) +{ + return 0; +} + +static inline int mmap_hook_validate(unsigned long prev_start, + const vma_flags_t *prev_flags, + const struct vm_area_struct *vma) +{ + return 0; +} #endif =20 struct vm_area_struct *__install_special_mapping(struct mm_struct *mm, diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/du= p.h index 2fd422789717..2986ae6ca1e5 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -1359,13 +1359,23 @@ static inline int vfs_mmap_prepare(struct file *fil= e, struct vm_area_desc *desc) return file->f_op->mmap_prepare(desc); } =20 +int mmap_prepare_validate(const struct vm_area_desc *prev_desc, + const struct vm_area_desc *desc); + static inline int __compat_vma_mmap(struct vm_area_desc *desc, struct vm_area_struct *vma) { + struct vm_area_desc prev_desc; int err; =20 + /* Derive state prior to mmap_prepare hook. */ + compat_set_desc_from_vma(&prev_desc, desc->file, vma); /* Perform any preparatory tasks for mmap action. */ err =3D mmap_action_prepare(desc); + if (err) + return err; + /* Check the caller did nothing crazy. */ + err =3D mmap_prepare_validate(&prev_desc, desc); if (err) return err; /* Update the VMA from the descriptor. */ --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 774E3481FD0; Mon, 14 Sep 2026 15:01:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Mon, 14 Sep 2026 15:01:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398107; bh=u1RlWGqGnqWzw8PbO9zbWrmr/LvMwLtC2FngYjobCv0=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=RMvtKc2Efv1pbG8Mv02sdIQx9hVQ8bJXtPwMHTd3MYYD4WYoHNaa5fd2EKNkl4LXb dAIBQ6wtgd+YqE6LzncYMxkdsEIAOOv5BBJOPrgsl6UEA2CyOPUlz/zhtzL3+K9n+/ kagkxOWzJtVy1alQpmCXVXCDICc1XxeSbucOdqnmZwdbwEmjNaMYuWiK+M3PHTU3tD AESRcc/JnMvD/20iN5iXM7DjY8mImZJGF+9Wx82wOnx+grvK1o+Ua3kR46QNBj6QXG CFH8rin/gxmRPwAwD/P8iy2uVPHdoMrR7FDPBjEwPjzBw5ZhKY639RgmIWFGg3yU6H Xex7+5jTAEb3g== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:25 +0100 Subject: [PATCH v2 05/40] mm/vma: ensure mmap_prepare doesn't set actions on a mergeable vma Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-5-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=1311; i=ljs@kernel.org; h=from:subject:message-id; bh=1okRmprRB6sg9Mfs+wXkHjRqWyxan5/JZ1tZ/n8xX5k=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK979XCjVm5Vt0rWwokPzqrcefr21bmtTD3mmy1XO ymdtnN16ShlYRDjYpAVU2R5/kV8f5BI2LzOC/5uMHNYmUCGMHBxCsBEWjMZGa48qTrE29h+0iez pVMnw/Wbv9kGjcK+Mw49R1UDlC+pxDL897ryeHbcenOG1btqTlsc2qnDq6J5ZpO7jvmDCmO/5fs XcgMA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 When a user requests an mmap_action be performed in mmap_prepare, this involves populating the VMA range with data. However, if the VMA is mergeable, it might then mistakenly be merged with another VMA without having populated the range. Every mmap action currently available sets VMA flags such that the VMA cannot be merged. However, to ensure that no future mmap action falls foul of this, assert that this is the case upon mmap_prepare validation. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/vma.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/vma.c b/mm/vma.c index 626a18c08a26..2648fb0e1995 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2809,6 +2809,15 @@ static int mmap_validate(unsigned long prev_start, int mmap_prepare_validate(const struct vm_area_desc *prev_desc, const struct vm_area_desc *desc) { + /* + * It is not valid to execute mmap actions for VMAs which can be merged, + * as any such merge would leave portions of the mapping incorrectly + * unmapped. + */ + if (vma_flags_can_merge(&desc->vma_flags) && + WARN_ON_ONCE(desc->action.type !=3D MMAP_NOTHING)) + return -EINVAL; + return mmap_validate(prev_desc->start, desc->start, &prev_desc->vma_flags, &desc->vma_flags); } --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 D445F486403; Mon, 14 Sep 2026 15:02:15 +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=1789398138; cv=none; b=fRJJ16+b9Ka28YfAgvQ2800EZzFgrGIA/Q8QBUZe94YpSjHo4seq/SSLAdNgAANZn0J2O9F51MFFobQWjJk+vDWoJtAxAqERAp9wcfmRG+E774INmQ3xCePJ4PTypTTDcRfTiEgJVW2DjuyE1yyJhvp6WE7KAPIR7vnCaiuhESo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398138; c=relaxed/simple; bh=qfAyj0ybwJ4DJXdH6Vmm7/5PNAiQvM8UyRor9dsN0CI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=c2GrK6LqdWfJ9c+bNbXl1s09BDunIcmEOzgwLkYfy37o7B8JKC85s/MJHB1V++6v2bwfJ6NpUOOiWQWcS5P5rnC046/sesweDvnVa31ruUU67LCvRPcFJ0Fkl+SACDC4UhN5wzwLASR+TwNC2Kg/J519WgfFYqOA33M4aIDKgN8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FbtUOEcR; 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="FbtUOEcR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E3AE1F00893; Mon, 14 Sep 2026 15:01:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398134; bh=6fTmcmc+a4IUNwae9Nxcfez5sumoqebDO82GfLQBZkY=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=FbtUOEcRtZhns+Zw5yDfZqYhCI9CoETgI/1XfZ9DKiPZsjMzAh+cNfYgAHHBh5Ze2 UJCWSzDSUrpDDioCW/uL/8TzzzHYOmlUyDKnjG7KAw9Hmdf+8JXoV637sifD5wOGXA XslPofXx4VNhS1MijPFO6ayUd9qNWgPpYBakikTOKGGOLNMo09ft26O9TA/7cY3WLP zfR0ZJHRxRYb05Ub2a4s0/yoqCtwb/jfek5lrNzBxvsCj7aQ/qpc1WvNqTz0Ugn2ww Bx7L/tBNLBhxSd9KD1w1dJcxqZ+ZD4kcHBAWWQ5gzQPj36qivS4A+qkoEGLBOX8UIf LiCbaNkrc9lFQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:26 +0100 Subject: [PATCH v2 06/40] mm: make map_kernel_pages_[prepare,complete] internal and unexported Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-6-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2508; i=ljs@kernel.org; h=from:subject:message-id; bh=qfAyj0ybwJ4DJXdH6Vmm7/5PNAiQvM8UyRor9dsN0CI=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK+r5PCoDJPNUgphWKkfuuoH/9JZFr1nKwtUDSP3z Cn7oqndUcrCIMbFICumyPL8i/j+IJGweZ0X/N1g5rAygQxh4OIUgInwyzIyNF9mWVXYPW1vb7ZM 66s/zkcn7tkx+5WDrPIbuwuVNj2Rmxj+RxzIutOxsltC5Kf/lBLGusmzUz9u109jY071Df1+RmI 3BwA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 There's no reason to export the symbols for these functions which are only called from internal mm logic, additionally there's no reason for them to be declared in mm.h. This patch therefore removes the exports and moves the declarations to mm/internal.h. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 3 --- mm/internal.h | 3 +++ mm/memory.c | 2 -- 3 files changed, 3 insertions(+), 5 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 68250ece4219..0c17f0932b76 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4768,9 +4768,6 @@ int remap_pfn_range(struct vm_area_struct *vma, unsig= ned long addr, int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct pag= e *); int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, struct page **pages, unsigned long *num); -int map_kernel_pages_prepare(struct vm_area_desc *desc); -int map_kernel_pages_complete(struct vm_area_struct *vma, - struct mmap_action *action); int vm_map_pages(struct vm_area_struct *vma, struct page **pages, unsigned long num); int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages, diff --git a/mm/internal.h b/mm/internal.h index 1ed11eaf276a..0cd26277a4c8 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1511,6 +1511,9 @@ int remap_pfn_range_prepare(struct vm_area_desc *desc= ); int remap_pfn_range_complete(struct vm_area_struct *vma, struct mmap_action *action); int simple_ioremap_prepare(struct vm_area_desc *desc); +int map_kernel_pages_prepare(struct vm_area_desc *desc); +int map_kernel_pages_complete(struct vm_area_struct *vma, + struct mmap_action *action); =20 static inline int io_remap_pfn_range_prepare(struct vm_area_desc *desc) { diff --git a/mm/memory.c b/mm/memory.c index 926276d41920..448342883e9d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2628,7 +2628,6 @@ int map_kernel_pages_prepare(struct vm_area_desc *des= c) =20 return 0; } -EXPORT_SYMBOL(map_kernel_pages_prepare); =20 int map_kernel_pages_complete(struct vm_area_struct *vma, struct mmap_action *action) @@ -2640,7 +2639,6 @@ int map_kernel_pages_complete(struct vm_area_struct *= vma, action->map_kernel.pages, &nr_pages, vma->vm_page_prot); } -EXPORT_SYMBOL(map_kernel_pages_complete); =20 /** * vm_insert_page - insert single page into user vma --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 7BB39483BE9; Mon, 14 Sep 2026 15:02:42 +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=1789398164; cv=none; b=Tg+BkNEUqFv9vjhS98IdczD7L4E7/+anGGdapX6kjIA741HSDtzWcF5w8LCEz2gCtTOs69FukoQTxWlp1A/B44BMaIZGYQM38WyCCLR61ClwbzTOM2aPrH+rTEcbhnsbtZ/wE8o7hev94YRol8UXxWTnzcKPwScjDYOIoftzvhU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398164; c=relaxed/simple; bh=HY4Q3Cfycqa6fp8N5aZLFaoVFjw/3MQxTeg608Oh/QQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=FFIKBpO9Mnk/PBMJR/N9N+vkRRexcS2elT77kIgxmIF99LNxexekZaU9UtlMRsVud2fFjoottZX+AZNh9Vn+X4JoLN+ZD/OuHvSaxSJDlObZSKA1SbgjDCHkRW7JR5+hIzn369N5WIEesNAfZjglsfyNbjTOT9LWLutpC1QIIQo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LosMDrZZ; 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="LosMDrZZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1884D1F000FF; Mon, 14 Sep 2026 15:02:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398162; bh=6WNH4ajOGiRyME4gV0hKpqyimaBUBR6xvgBKJbfZQV4=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=LosMDrZZjI+QrX79kGmc0Y7vfXqOojWfZcIQPNqK8y+pCBEfaW3BGQkgB/waeaSKW ptv1ekb6f/qS/4lf2b9Y4mYrZIJPJM38mAercgr5eON2xxEdqHtnVUYwc+bhdFBFd7 JUOyLUmBSsfp8s0yeqX1ILz0qq87+M7D+2HXRNrM+mrD8ZO1GBkYLMJNIpTmlLWWme kCRpYF9FITLLy296+jZePjhEvUpWxgoaj5DGHM4gOF9UEPA7RWsolGONiG650q8STY SKYYrv733ibMIKX/+HECmhlmlC4mFyhxLdCVJJWuR8AlgmxxnAFK+BgW2QwjNINvLt NPk1WayinSQHw== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:27 +0100 Subject: [PATCH v2 07/40] mm/vma: tidy up map kernel pages enum values Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-7-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=3944; i=ljs@kernel.org; h=from:subject:message-id; bh=HY4Q3Cfycqa6fp8N5aZLFaoVFjw/3MQxTeg608Oh/QQ=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK+TT2527Ama6l20Xs9lW3WLn8fqOf/KexnPtX76/ U1oC+PxjlIWBjEuBlkxRZbnX8T3B4mEzeu84O8GM4eVCWQIAxenAEyEs5/hv0fsPuNnr35sPNf0 6Lt6osJhFwedhEObvN7d2LXE7Of3Z+0M/8OqLR992WhxcV3K9XdavKmzV20+xHFSwvLEEa8Nyx/ uDGYDAA== X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 MMAP_MAP_KERNEL_PAGES is a mouthful, discard the MAP_ as that's implied by MMAP. Also while we're here delete useless comments for mmap actions whose names clearly indicate what they are for. Also update the userland VMA tests to reflect this change. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 2 +- include/linux/mm_types.h | 8 ++++---- mm/util.c | 8 ++++---- tools/testing/vma/include/dup.h | 8 ++++---- 4 files changed, 13 insertions(+), 13 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0c17f0932b76..a1f2d375cf7d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4623,7 +4623,7 @@ static inline void mmap_action_map_kernel_pages(struc= t vm_area_desc *desc, { struct mmap_action *action =3D &desc->action; =20 - action->type =3D MMAP_MAP_KERNEL_PAGES; + action->type =3D MMAP_KERNEL_PAGES; action->map_kernel.start =3D start; action->map_kernel.pages =3D pages; action->map_kernel.nr_pages =3D nr_pages; diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5413bd10fff2..9ca2ea3664bc 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -815,11 +815,11 @@ struct pfnmap_track_ctx { =20 /* What action should be taken after an .mmap_prepare call is complete? */ enum mmap_action_type { - MMAP_NOTHING, /* Mapping is complete, no further action. */ - MMAP_REMAP_PFN, /* Remap PFN range. */ - MMAP_IO_REMAP_PFN, /* I/O remap PFN range. */ + MMAP_NOTHING, + MMAP_REMAP_PFN, + MMAP_IO_REMAP_PFN, MMAP_SIMPLE_IO_REMAP, /* I/O remap with guardrails. */ - MMAP_MAP_KERNEL_PAGES, /* Map kernel page range from array. */ + MMAP_KERNEL_PAGES, /* Map kernel page range from array. */ }; =20 /* diff --git a/mm/util.c b/mm/util.c index bdd5923eebc7..438170490e7f 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1467,7 +1467,7 @@ int mmap_action_prepare(struct vm_area_desc *desc) return io_remap_pfn_range_prepare(desc); case MMAP_SIMPLE_IO_REMAP: return simple_ioremap_prepare(desc); - case MMAP_MAP_KERNEL_PAGES: + case MMAP_KERNEL_PAGES: return map_kernel_pages_prepare(desc); } =20 @@ -1498,7 +1498,7 @@ int mmap_action_complete(struct vm_area_struct *vma, case MMAP_REMAP_PFN: err =3D remap_pfn_range_complete(vma, action); break; - case MMAP_MAP_KERNEL_PAGES: + case MMAP_KERNEL_PAGES: err =3D map_kernel_pages_complete(vma, action); break; case MMAP_IO_REMAP_PFN: @@ -1521,7 +1521,7 @@ int mmap_action_prepare(struct vm_area_desc *desc) case MMAP_REMAP_PFN: case MMAP_IO_REMAP_PFN: case MMAP_SIMPLE_IO_REMAP: - case MMAP_MAP_KERNEL_PAGES: + case MMAP_KERNEL_PAGES: WARN_ON_ONCE(1); /* nommu cannot handle these. */ break; } @@ -1542,7 +1542,7 @@ int mmap_action_complete(struct vm_area_struct *vma, case MMAP_REMAP_PFN: case MMAP_IO_REMAP_PFN: case MMAP_SIMPLE_IO_REMAP: - case MMAP_MAP_KERNEL_PAGES: + case MMAP_KERNEL_PAGES: WARN_ON_ONCE(1); /* nommu cannot handle this. */ =20 err =3D -EINVAL; diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/du= p.h index 2986ae6ca1e5..1098655a5f4a 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -454,11 +454,11 @@ static __always_inline bool vma_flags_empty(const vma= _flags_t *flags) =20 /* What action should be taken after an .mmap_prepare call is complete? */ enum mmap_action_type { - MMAP_NOTHING, /* Mapping is complete, no further action. */ - MMAP_REMAP_PFN, /* Remap PFN range. */ - MMAP_IO_REMAP_PFN, /* I/O remap PFN range. */ + MMAP_NOTHING, + MMAP_REMAP_PFN, + MMAP_IO_REMAP_PFN, MMAP_SIMPLE_IO_REMAP, /* I/O remap with guardrails. */ - MMAP_MAP_KERNEL_PAGES, /* Map kernel page range from an array. */ + MMAP_KERNEL_PAGES, /* Map kernel page range from array. */ }; =20 /* --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 0977D47DFB9; Mon, 14 Sep 2026 15:03:09 +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=1789398191; cv=none; b=pOsWxV8nW3ubCYrNncmrEGM/T37xUYQBIMe5hshXBu0BfoTcfhe1/23BeYe2r5s2kqUjhikqzXmrtn9JTtDhOtA2YMsK+Moshp0qMPbamIjPTauTOZwLJAPBfvVGY9ynj6E0Qz1zhbeQcsbvhvVUL6S5h34n8QF1bvCfuHkmbn4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398191; c=relaxed/simple; bh=KTopW2/sxfulwf59WpGpEZd8vJ7w9dPdvS81FaJO3IY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=p2YUL64TcEOflQalDBAJ+y17EFYl3mZJJq7/3RL/2+mJELtQuNJMycQArRaThnlSzOOxOzHGry8M68tL96c93chWrEb06mZ38U/Knqlv+qgb2kHPuJ6gCynuxBd0B66ICKYEHReQrgaSpCV/Dui8PVcg4K/bJ2VQBHbFRw1WKo8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lPD9gr6x; 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="lPD9gr6x" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 936841F00893; Mon, 14 Sep 2026 15:02:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398189; bh=dIglkKIN3/W3qByFkLNG0bBOvws5ewzjysWBscsc5Hk=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=lPD9gr6x3UMX0UN1vV291JL3OZaZshRC1NwUhZmw/mMNefV6y+atGM5mjggFSf5mO sPHAAfn8fXkFUrLMBdHi3LxbDJX8VQrg8zLAeehpP3Noi3scH1mCNMq391jWrGhPNZ 4lFUyIMXKK1i2Ng7o4HG2+P9TSMlXGYFNUpgACzx1SshXx+0dl3dtlvtnAjAOu6Ony 1PNw/EpTBu9/DWr7T8qNne5LEJzkMvftVxRJ7W65WXDXlwaIvVwCHrwF78ZZicGH6d xZArejpZ5SOtZBL+IYbTqkDEjNrmCsh5UhFhqpF+uQfhsFhnDy6KTh0MG6e7+Wsfqi XflhGt9q+Rsfg== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:28 +0100 Subject: [PATCH v2 08/40] mm: add mmap action for discontiguous kernel page mapping Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-8-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=12992; i=ljs@kernel.org; h=from:subject:message-id; bh=KTopW2/sxfulwf59WpGpEZd8vJ7w9dPdvS81FaJO3IY=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK872izbIBZ4ZdJMQT5Vsb8PGZZLLMnh8zDsnmf4r Wqhg7RfRykLgxgXg6yYIsvzL+L7g0TC5nVe8HeDmcPKBDKEgYtTACaSVcfwzypb7MreTUf6Yypu h6meXNKxeKrlnLmZEZrzwoSFsyxi3zMy7JH6lHItklfqycGCZbIMDGvtGj+3Gdyrc7ktXK/eEb2 HFQA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 The existing kernel page mapping mmap actions allow for partial and full mapping of an array of struct page pointers. However some drivers require the mapping of discontiguous ranges. Permit this by providing discontig_kernel_page_ops which allows a driver to specify how the operation should begin and how batches of pages should be retrieved. It uses the minimum exposed interface to do so, providing address, page offset and both vm_private_data state and a local private state object. ops->init can establish state for the operation, and ops->get outputs the pages to map and their count. Should an error arise the core unmaps the VMA, invoking vm_ops->close, which is therefore where any state established by ops->init is released. Batches may not exceed the VMA, but may map less than its full range in case the driver wishes to allow the user to map an area larger than the available data. To use it, users invoke mmap_action_map_discontig_kernel_pages() with initial local private state and a set of operations. Users can then use one of the provided helper functions to perform an action: * discontig_kernel_map_abort() - Abort and leave the mapping as it has been accumulated so far. * discontig_kernel_map_page() - Map a single page, or a compound page given its head page. * discontig_kernel_map_page_range() - Maps a struct page ** array of a specified count. The userland VMA tests are updated accordingly. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 45 +++++++++++++++++ include/linux/mm_types.h | 44 +++++++++++++++- mm/internal.h | 3 ++ mm/memory.c | 108 ++++++++++++++++++++++++++++++++++++= ++-- mm/util.c | 7 +++ tools/testing/vma/include/dup.h | 11 +++- 6 files changed, 209 insertions(+), 9 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index a1f2d375cf7d..2a92193ac6a5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4647,10 +4647,55 @@ static inline void mmap_action_map_kernel_pages_ful= l(struct vm_area_desc *desc, vma_desc_pages(desc)); } =20 +static inline +void mmap_action_map_discontig_kernel_pages(struct vm_area_desc *desc, + void *init_private, const struct discontig_kernel_page_ops *ops) +{ + struct mmap_action *action =3D &desc->action; + + action->type =3D MMAP_DISCONTIG_KERNEL_PAGES; + action->map_kernel_discontig.init_private =3D init_private; + action->map_kernel_discontig.ops =3D ops; +} + int mmap_action_prepare(struct vm_area_desc *desc); int mmap_action_complete(struct vm_area_struct *vma, struct mmap_action *action, bool is_compat); =20 +static inline void +discontig_kernel_map_abort(struct discontig_kernel_page_state *state) +{ + state->action =3D DISCONTIG_KERNEL_PAGE_ABORT; +} + +static inline void +discontig_kernel_map_page(struct discontig_kernel_page_state *state, + struct page *page) +{ + struct folio *folio =3D page_folio(page); + + if (folio_test_large(folio)) { + VM_WARN_ON_ONCE(page !=3D folio_page(folio, 0)); + state->action =3D DISCONTIG_KERNEL_PAGE_MAP_COMPOUND_PAGE; + state->__folio =3D folio; + state->__nr_pages =3D min(state->nr_pages_remain, + folio_nr_pages(folio)); + } else { + state->action =3D DISCONTIG_KERNEL_PAGE_MAP_PAGE; + state->__page =3D page; + state->__nr_pages =3D 1; + } +} + +static inline void +discontig_kernel_map_page_range(struct discontig_kernel_page_state *state, + struct page **page_arr, unsigned long nr_pages) +{ + state->action =3D DISCONTIG_KERNEL_PAGE_MAP_PAGE_RANGE; + state->__page_arr =3D page_arr; + state->__nr_pages =3D nr_pages; +} + /* Look up the first VMA which exactly match the interval vm_start ... vm_= end */ static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm, unsigned long vm_start, unsigned long vm_end) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 9ca2ea3664bc..0cb4f9603956 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -818,8 +818,44 @@ enum mmap_action_type { MMAP_NOTHING, MMAP_REMAP_PFN, MMAP_IO_REMAP_PFN, - MMAP_SIMPLE_IO_REMAP, /* I/O remap with guardrails. */ - MMAP_KERNEL_PAGES, /* Map kernel page range from array. */ + MMAP_SIMPLE_IO_REMAP, /* I/O remap with guardrails. */ + MMAP_KERNEL_PAGES, /* Map kernel page range from array. */ + MMAP_DISCONTIG_KERNEL_PAGES, /* Map kernel discontig page range. */ +}; + +enum discontig_kernel_page_action { + DISCONTIG_KERNEL_PAGE_ABORT, + DISCONTIG_KERNEL_PAGE_MAP_PAGE, + DISCONTIG_KERNEL_PAGE_MAP_COMPOUND_PAGE, + DISCONTIG_KERNEL_PAGE_MAP_PAGE_RANGE, +}; + +struct discontig_kernel_page_state { + /* Map state. */ + const unsigned long start; /* Start address of VMA. */ + const unsigned long end; /* End address of VMA. */ + unsigned long addr; /* The current address to be mapped. */ + pgoff_t pgoff; /* The current pgoff to be mapped. */ + unsigned long nr_pages_mapped; /* The number of pages mapped. */ + unsigned long nr_pages_remain; /* The number of pages remaining. */ + + /* User-defined state. */ + void *vm_private_data; /* VMA private data. */ + void *private; /* Mapping private data. */ + + /* Users should not touch these, use discontig_kernel_map_*() helpers. */ + enum discontig_kernel_page_action action; + union { + struct page *__page; + struct folio *__folio; + struct page **__page_arr; + }; + unsigned long __nr_pages; +}; + +struct discontig_kernel_page_ops { + int (*init)(void *vm_private_data, void **private); + int (*get)(struct discontig_kernel_page_state *state); }; =20 /* @@ -844,6 +880,10 @@ struct mmap_action { unsigned long nr_pages; pgoff_t pgoff; } map_kernel; + struct { + void *init_private; + const struct discontig_kernel_page_ops *ops; + } map_kernel_discontig; }; enum mmap_action_type type; =20 diff --git a/mm/internal.h b/mm/internal.h index 0cd26277a4c8..3a395e8c224c 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1514,6 +1514,9 @@ int simple_ioremap_prepare(struct vm_area_desc *desc); int map_kernel_pages_prepare(struct vm_area_desc *desc); int map_kernel_pages_complete(struct vm_area_struct *vma, struct mmap_action *action); +int map_discontig_kernel_pages_prepare(struct vm_area_desc *desc); +int map_discontig_kernel_pages_complete(struct vm_area_struct *vma, + struct mmap_action *action); =20 static inline int io_remap_pfn_range_prepare(struct vm_area_desc *desc) { diff --git a/mm/memory.c b/mm/memory.c index 448342883e9d..42f084517247 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2609,17 +2609,23 @@ int vm_insert_pages(struct vm_area_struct *vma, uns= igned long addr, } EXPORT_SYMBOL(vm_insert_pages); =20 +static void __map_kernel_pages_prepare(struct vm_area_desc *desc) +{ + if (vma_desc_test(desc, VMA_MIXEDMAP_BIT)) + return; + + VM_WARN_ON_ONCE(mmap_read_trylock(desc->mm)); + VM_WARN_ON_ONCE(vma_desc_test(desc, VMA_PFNMAP_BIT)); + vma_desc_set_flags(desc, VMA_MIXEDMAP_BIT); +} + int map_kernel_pages_prepare(struct vm_area_desc *desc) { const struct mmap_action *action =3D &desc->action; const unsigned long addr =3D action->map_kernel.start; unsigned long nr_pages, end; =20 - if (!vma_desc_test(desc, VMA_MIXEDMAP_BIT)) { - VM_WARN_ON_ONCE(mmap_read_trylock(desc->mm)); - VM_WARN_ON_ONCE(vma_desc_test(desc, VMA_PFNMAP_BIT)); - vma_desc_set_flags(desc, VMA_MIXEDMAP_BIT); - } + __map_kernel_pages_prepare(desc); =20 nr_pages =3D action->map_kernel.nr_pages; end =3D addr + PAGE_SIZE * nr_pages; @@ -2640,6 +2646,98 @@ int map_kernel_pages_complete(struct vm_area_struct = *vma, &nr_pages, vma->vm_page_prot); } =20 +int map_discontig_kernel_pages_prepare(struct vm_area_desc *desc) +{ + const struct mmap_action *action =3D &desc->action; + const struct discontig_kernel_page_ops *ops =3D + action->map_kernel_discontig.ops; + + /* At minimum need to be able to get pages. */ + if (WARN_ON_ONCE(!ops->get)) + return -EINVAL; + + __map_kernel_pages_prepare(desc); + return 0; +} + +static int apply_discontig_action(struct vm_area_struct *vma, + struct discontig_kernel_page_state *state) +{ + unsigned long nr_pages =3D state->__nr_pages; + unsigned long addr =3D state->addr; + unsigned long i; + + if (state->action =3D=3D DISCONTIG_KERNEL_PAGE_MAP_PAGE) + return insert_page(vma, addr, state->__page, + vma->vm_page_prot, /*mkwrite=3D*/false); + if (state->action =3D=3D DISCONTIG_KERNEL_PAGE_MAP_PAGE_RANGE) + return insert_pages(vma, addr, state->__page_arr, + &nr_pages, vma->vm_page_prot); + + /* Compound folio - have to iterate through each page. */ + for (i =3D 0; i < nr_pages; i++, addr +=3D PAGE_SIZE) { + struct page *page =3D folio_page(state->__folio, i); + int err; + + err =3D insert_page(vma, addr, page, vma->vm_page_prot, + /*mkwrite=3D*/false); + if (err) + return err; + } + return 0; +} + +int map_discontig_kernel_pages_complete(struct vm_area_struct *vma, + struct mmap_action *action) +{ + const struct discontig_kernel_page_ops *ops =3D + action->map_kernel_discontig.ops; + struct discontig_kernel_page_state state =3D { + .start =3D vma->vm_start, + .end =3D vma->vm_end, + .addr =3D vma->vm_start, + .pgoff =3D vma->vm_pgoff, + .nr_pages_mapped =3D 0, + .nr_pages_remain =3D vma_pages(vma), + .vm_private_data =3D vma->vm_private_data, + .private =3D action->map_kernel_discontig.init_private, + }; + int err =3D 0; + + if (ops->init) + err =3D ops->init(vma->vm_private_data, &state.private); + if (err) + return err; + + do { + unsigned long end, pgoff_end; + unsigned long nr_pages; + + /* Default to abort. */ + state.action =3D DISCONTIG_KERNEL_PAGE_ABORT; + err =3D ops->get(&state); + if (err || state.action =3D=3D DISCONTIG_KERNEL_PAGE_ABORT) + return err; + nr_pages =3D state.__nr_pages; + + if (!nr_pages || nr_pages > state.nr_pages_remain) + return -EINVAL; + end =3D state.addr + PAGE_SIZE * nr_pages; + pgoff_end =3D state.pgoff + nr_pages; + + err =3D apply_discontig_action(vma, &state); + if (err) + return err; + + state.addr =3D end; + state.pgoff =3D pgoff_end; + state.nr_pages_mapped +=3D nr_pages; + state.nr_pages_remain -=3D nr_pages; + } while (state.addr < vma->vm_end); + + return 0; +} + /** * vm_insert_page - insert single page into user vma * @vma: user vma to map to diff --git a/mm/util.c b/mm/util.c index 438170490e7f..c5ee52aede1e 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1469,6 +1469,8 @@ int mmap_action_prepare(struct vm_area_desc *desc) return simple_ioremap_prepare(desc); case MMAP_KERNEL_PAGES: return map_kernel_pages_prepare(desc); + case MMAP_DISCONTIG_KERNEL_PAGES: + return map_discontig_kernel_pages_prepare(desc); } =20 WARN_ON_ONCE(1); @@ -1501,6 +1503,9 @@ int mmap_action_complete(struct vm_area_struct *vma, case MMAP_KERNEL_PAGES: err =3D map_kernel_pages_complete(vma, action); break; + case MMAP_DISCONTIG_KERNEL_PAGES: + err =3D map_discontig_kernel_pages_complete(vma, action); + break; case MMAP_IO_REMAP_PFN: case MMAP_SIMPLE_IO_REMAP: /* Should have been delegated. */ @@ -1522,6 +1527,7 @@ int mmap_action_prepare(struct vm_area_desc *desc) case MMAP_IO_REMAP_PFN: case MMAP_SIMPLE_IO_REMAP: case MMAP_KERNEL_PAGES: + case MMAP_DISCONTIG_KERNEL_PAGES: WARN_ON_ONCE(1); /* nommu cannot handle these. */ break; } @@ -1543,6 +1549,7 @@ int mmap_action_complete(struct vm_area_struct *vma, case MMAP_IO_REMAP_PFN: case MMAP_SIMPLE_IO_REMAP: case MMAP_KERNEL_PAGES: + case MMAP_DISCONTIG_KERNEL_PAGES: WARN_ON_ONCE(1); /* nommu cannot handle this. */ =20 err =3D -EINVAL; diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/du= p.h index 1098655a5f4a..1d5f6b3cbd21 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -457,14 +457,17 @@ enum mmap_action_type { MMAP_NOTHING, MMAP_REMAP_PFN, MMAP_IO_REMAP_PFN, - MMAP_SIMPLE_IO_REMAP, /* I/O remap with guardrails. */ - MMAP_KERNEL_PAGES, /* Map kernel page range from array. */ + MMAP_SIMPLE_IO_REMAP, /* I/O remap with guardrails. */ + MMAP_KERNEL_PAGES, /* Map kernel page range from array. */ + MMAP_DISCONTIG_KERNEL_PAGES, /* Map kernel discontig page range. */ }; =20 /* * Describes an action an mmap_prepare hook can instruct to be taken to co= mplete * the mapping of a VMA. Specified in vm_area_desc. */ +struct discontig_kernel_page_ops; + struct mmap_action { union { struct { @@ -483,6 +486,10 @@ struct mmap_action { unsigned long nr_pages; pgoff_t pgoff; } map_kernel; + struct { + void *init_private; + const struct discontig_kernel_page_ops *ops; + } map_kernel_discontig; }; enum mmap_action_type type; =20 --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 8A78C468C12; Mon, 14 Sep 2026 15:03:37 +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=1789398219; cv=none; b=c9tJ031zYznF8ZPk/lBkri6tyXffHDqYTAzRG5yzMm9VFcea5SM6dYXIs+HYvySTL7V5AoAN1Xm7qa3jdEVtaz1f+ZqAeRM6DewLZ5Y4rQ9wlPU8gQKDm/R0qZ5fEID9qKriSgeHUK/Wpeb/YAlvQjXdiP6c1IvudEgDutQFc8c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398219; c=relaxed/simple; bh=ku45FxaXB5jDrWF7xzKWcksoG8pHB6sirZFvJa9Q21A=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=tUylWjrcGZni5Mh83XXOz1SQEtOfI8PTCPgtXcQx+wXqy4ypivi84jT2lHuWlbBJx24167JPn6xJ00FUU862DYrB5ZpQzfvQiSTGWa8PhyAlL2HZFdO1XbBhJo8Dhx7njH/3I14w25XFUIPSd4SgPhuG9gBG7RBHxwhPtV1T1YI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fSetHrBg; 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="fSetHrBg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E7151F000FF; Mon, 14 Sep 2026 15:03:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398217; bh=CxJPdlL4ukdxMfUTmFq0FMtswRM14QRAmb+14GeHlio=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=fSetHrBgzPj2+SmYbcSwP+UBBu7oqgySlvgwtfGMifcj7mtjDTFfovm9LWqpVGZ4E d7LbTBCClp6uaGQ5kpmXzygZI5dGPwY1CEx4yIyt90eoup2gdN3krNS6lZoRG+OzgG T/Y9KDrh7F7i8HLE8S1YLHJ7wur8fIhpd0Oig2d5jDtbELt5zPgD4WGUXZ55AClFJ6 ASecwckytcje5tQBKYzFUV5Mw5My6byzSUXajoDaKg5mI+g+V7W6+ZjMzxuRWpRDMm 1GaiGTCu4y6Xp9Vd+enrCQ22MdEsms5v3l1aX4gNaStO6nRlnTtDOQ0M01FETTbnEN AVukgG7gVlrgw== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:29 +0100 Subject: [PATCH v2 09/40] docs: filesystems: update mmap_prepare docs for discontig kernel pgs Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-9-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> To: Andrew Morton , "Liam R. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=4561; i=ljs@kernel.org; h=from:subject:message-id; bh=ku45FxaXB5jDrWF7xzKWcksoG8pHB6sirZFvJa9Q21A=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK+3CPBUi47Y4JZ9bPo5/xi/KbmTs6/O4NKvF01sq XRJmvOio5SFQYyLQVZMkeX5F/H9QSJh8zov+LvBzGFlAhnCwMUpABNhMmP4ZzX5sUNP1OVVti8E rzxqY01cr34luXPC401KRvvqUp8ermdkuHgi8u/r3VPWcjI+S5gfkrcl4COD0rrwyze47s3oC9X 8wAEA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Describe the newly introduced discontiguous kernel page mapping mechanism, detailing how to use it sensibly and how the API looks. Explicitly detail the various discontiguous actions available and how to use them. Signed-off-by: Lorenzo Stoakes (ARM) --- Documentation/filesystems/mmap_prepare.rst | 81 ++++++++++++++++++++++++++= ++++ 1 file changed, 81 insertions(+) diff --git a/Documentation/filesystems/mmap_prepare.rst b/Documentation/fil= esystems/mmap_prepare.rst index 82c99c95ad85..a476e1006bf1 100644 --- a/Documentation/filesystems/mmap_prepare.rst +++ b/Documentation/filesystems/mmap_prepare.rst @@ -164,5 +164,86 @@ pointer. These are: sufficient entries in the page array to cover the entire range of the described VMA. =20 +* mmap_action_map_discontig_kernel_pages() - Maps a discontiguous range of + `struct page` pointers over the VMA. They must span from the start of th= e VMA, + but may terminate prior to the end (leaving the remainder unmapped). + **NOTE:** The ``action`` field should never normally be manipulated direct= ly, rather you ought to use one of these helpers. + +Discontiguous Actions +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +Some actions can be performed across discontiguous ranges. + +Map kernel pages +---------------- + +To map kernel pages discontiguously, you must provide hooks using ``struct +discontig_kernel_page_ops``: + +.. code-block:: C + + struct discontig_kernel_page_ops { + int (*init)(void *vm_private_data, void **private); + int (*get)(struct discontig_kernel_page_state *state); + }; + +The ``init`` hook is optional and allows state to be established before the +operation starts, for instance taking a reference count. Nothing is invoked +after the operation, so ``init`` must not leave locks held, and state that= must +be released once the mapping goes away should be released in +``vm_ops->close``. + +The ``init`` hook, if provided, is invoked prior to the operation starting= . It +may update what is pointed to by ``vm_private_data`` and/or ``private``. I= f an +error is returned, then the operation is aborted. The ``private`` field ca= n be +reassigned. + +**NOTE:** The operation may sleep between invocations of ``get``, so locks +needed to stabilise state must be taken and released within each hook. + +The ``get`` handler is the key means through which the operation is +executed. The current state of the operation is provided through ``struct +discontig_kernel_page_state``: + +.. code-block:: C + + struct discontig_kernel_page_state { + /* Map state. */ + unsigned long start; /* Start address of VMA. */ + unsigned long end; /* End address of VMA. */ + unsigned long addr; /* The current address to be mappe= d. */ + pgoff_t pgoff; /* The current pgoff to be mapped.= */ + unsigned long nr_pages_mapped; /* The number of pages mapped. */ + unsigned long nr_pages_remain; /* The number of pages remaining. = */ + + /* User-defined state. */ + void *vm_private_data; /* VMA private data. */ + void *private; /* Mapping private data. */ + + /* Users should not touch these, use discontig_kernel_map_*() help= ers. */ + ... internal fields ... + }; + +With ``private`` being an additional user-controllable state variable, +initialised via ``mmap_action_map_discontig_kernel_pages()``, and +``vm_private_data`` being equal to the ``desc->private_data`` field set in +the ``mmap_prepare()`` hook. + +In the ``get`` hook, the user must choose how to map kernel pages: + +* ``discontig_kernel_map_abort()`` - Call this to abort the operation, wha= tever + has been mapped so far will be retained, the rest of the mapping will SI= GBUS + if accessed. +* ``discontig_kernel_map_page()`` - Maps a single page, correctly handling + compound pages (if the compound page is bigger than the remaining pages = in the + VMA, then only those pages that fit will be mapped). For a compound page= , the + head page must be passed. +* ``discontig_kernel_map_page_range()`` - Map an array of pages of a speci= fied + size. Note that if the number of pages specified exceeds the VMA size th= en an + error will arise. + +If an error arises after ``init`` succeeded, the core unmaps the VMA, invo= king +``vm_ops->close`` if set, which is therefore the place to release any state +that ``init`` established. --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 32E584854EB; Mon, 14 Sep 2026 15:04:04 +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=1789398247; cv=none; b=W3yutzMaaizEoCdtgUrQRLcsUch02Eev/be4qu3HQtnZjZzD8lDMF3TbDUeL6Udlmlg8nw03Y/IGMtybMXLxbPUp/GgY7O2KckZs5NWHl0NZReope+e3mByzKvcHh1K5RKf9avtKsccUTd95vsp4UYSr4S+fUkTBCMnVphGHWBs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398247; c=relaxed/simple; bh=GUpTHNxmxWarSVjd88RVgsA6FQygd+NcCuy3YFJiswg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ZOB25KbZmFzCTLi+Bglu2HaocHR1K4TOYfGy7WHWXrCb4jneVxpNLr6dKv3uoSgFLxCzBCzAVWGiML6ygT1I8TwxIyYqab9/acMK1hYADqFaGsKP3wDs2Fwi68ItvXm+HMHnan58eevQiTIR5gzLKXfqyT6N9ufZE+PZEF2BQng= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O+2yR+Gz; 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="O+2yR+Gz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D1A41F00893; Mon, 14 Sep 2026 15:03:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398244; bh=3NscFRoiSw0VLcsrcN7WIQlCyh4L7cg6MA64F9Bvckc=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=O+2yR+GzyvNY1voG7/f8ZVHT93rVxgpL8XsI+IF8jWob+9y4QJLs9WNbvI5u2uZI4 8jwm80J4TEPRKHMI/fF9JwIyD4KMVWTZYa9Xa1Q6jP2pjrfmh+3R5rOcDV6+tFh0qk BPMaPLVOOx/1bR23u2+g31dBlFWlYoNrA/qO3GUmKZlEes/wEhZX6g937fjftPF1rd Gh0nLKzieDlOC4lnc+IlLrFQ3ajJZq7ozkNKzEmlgjCgElroomjCystDaYutw8WEcC pTndPiVROmqPhUP2X5CCNeqKIlShLBEE41NDxrUMltsx/QwjYt91IwWq0ysLkZiMCG kTmtQdKuZAiqg== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:30 +0100 Subject: [PATCH v2 10/40] drivers/usb/mon: update to use mmap_prepare + map kernel pages Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-10-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=6221; i=ljs@kernel.org; h=from:subject:message-id; bh=GUpTHNxmxWarSVjd88RVgsA6FQygd+NcCuy3YFJiswg=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK/vn/Vj/uFpybwPt1Wx+5eeLFooMnOba09gtZWKx 4RPk3gEOkpZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjCR3GqGfzYp/OHeXgvyb/yY 9mx31+f7vswLnO8ZVmhY2ilxTiiSP8XI8I219qVawpriGQGOdl9/i/rqzBXwj7zDseal3NpVz85 KswAA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Replace the deprecated .mmap hook with its replacement .mmap_prepare. As part of this change, additionally take the approach of mapping pages upon mmap rather than providing a fault handler. The page span cannot be mutated when an mmap mapping is in place, so this is safe to do in advance (the MON_IOCT_RING_SIZE ioctl operation exits -EBUSY if it's attempted, gated by the rp->mmap_active reference count). Utilise the newly introduced mmap_action_map_discontig_kernel_pages() to do this, which allows for iteration over pages in mon_bin_discontig_get(). mon_bin_discontig_init() increments the rp->mmap_active reference count to stabilise page spans. Should an error arise the core unmaps the VMA and mon_bin_vma_close() drops the reference again. The vm_ops->close hook implemented in mon_bin_vma_close() will ensure correct reference count arithmetic upon unmap (with mon_bin_vma_open() accounting for splitting). The existing semantics are all retained, including not mapping past the range of available pages, with a SIGBUS being raised in a userland process that attempts to access past this point. Ultimately insert_page() is invoked to insert each page, which increments the reference count on each mapped page. This mimics what was being done previously, only we pre-map the entire range rather than doing so on demand. The existing fault handler did nothing that required demand paging, and was presumably implemented this way for historical reasons. One behavioural difference: pages are no longer faulted in on demand, so a page discarded with MADV_DONTNEED is not repopulated and a subsequent access raises SIGBUS, as with other pre-populated kernel mappings. Acked-by: Greg Kroah-Hartman Signed-off-by: Lorenzo Stoakes (ARM) --- drivers/usb/mon/mon_bin.c | 82 ++++++++++++++++++++++++++++++-------------= ---- 1 file changed, 53 insertions(+), 29 deletions(-) diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c index 687f6a8981f3..9d00b21a8153 100644 --- a/drivers/usb/mon/mon_bin.c +++ b/drivers/usb/mon/mon_bin.c @@ -1219,6 +1219,15 @@ mon_bin_poll(struct file *file, struct poll_table_st= ruct *wait) return mask; } =20 +static void __mon_bin_vma_open(struct mon_reader_bin *rp) +{ + unsigned long flags; + + spin_lock_irqsave(&rp->b_lock, flags); + rp->mmap_active++; + spin_unlock_irqrestore(&rp->b_lock, flags); +} + /* * open and close: just keep track of how many times the device is * mapped, to use the proper memory allocation function. @@ -1226,64 +1235,79 @@ mon_bin_poll(struct file *file, struct poll_table_s= truct *wait) static void mon_bin_vma_open(struct vm_area_struct *vma) { struct mon_reader_bin *rp =3D vma->vm_private_data; - unsigned long flags; =20 - spin_lock_irqsave(&rp->b_lock, flags); - rp->mmap_active++; - spin_unlock_irqrestore(&rp->b_lock, flags); + __mon_bin_vma_open(rp); } =20 -static void mon_bin_vma_close(struct vm_area_struct *vma) +static void __mon_bin_vma_close(struct mon_reader_bin *rp) { unsigned long flags; =20 - struct mon_reader_bin *rp =3D vma->vm_private_data; spin_lock_irqsave(&rp->b_lock, flags); rp->mmap_active--; spin_unlock_irqrestore(&rp->b_lock, flags); } =20 -/* - * Map ring pages to user space. - */ -static vm_fault_t mon_bin_vma_fault(struct vm_fault *vmf) +static void mon_bin_vma_close(struct vm_area_struct *vma) { - struct mon_reader_bin *rp =3D vmf->vma->vm_private_data; + struct mon_reader_bin *rp =3D vma->vm_private_data; + + __mon_bin_vma_close(rp); +} + +static const struct vm_operations_struct mon_bin_vm_ops =3D { + .open =3D mon_bin_vma_open, + .close =3D mon_bin_vma_close, +}; + +static int mon_bin_discontig_init(void *vm_private_data, void **private) +{ + struct mon_reader_bin *rp =3D vm_private_data; + + /* Dropped by mon_bin_vma_close() on unmap, including on error. */ + __mon_bin_vma_open(rp); + return 0; +} + +static int mon_bin_discontig_get(struct discontig_kernel_page_state *state) +{ + struct mon_reader_bin *rp =3D state->vm_private_data; unsigned long offset, chunk_idx; - struct page *pageptr; unsigned long flags; =20 spin_lock_irqsave(&rp->b_lock, flags); - offset =3D vmf->pgoff << PAGE_SHIFT; + + offset =3D state->pgoff << PAGE_SHIFT; if (offset >=3D rp->b_size) { spin_unlock_irqrestore(&rp->b_lock, flags); - return VM_FAULT_SIGBUS; + discontig_kernel_map_abort(state); + return 0; } chunk_idx =3D offset / CHUNK_SIZE; - pageptr =3D rp->b_vec[chunk_idx].pg; - get_page(pageptr); - vmf->page =3D pageptr; + discontig_kernel_map_page(state, rp->b_vec[chunk_idx].pg); + spin_unlock_irqrestore(&rp->b_lock, flags); return 0; } =20 -static const struct vm_operations_struct mon_bin_vm_ops =3D { - .open =3D mon_bin_vma_open, - .close =3D mon_bin_vma_close, - .fault =3D mon_bin_vma_fault, +static const struct discontig_kernel_page_ops mon_discontig_ops =3D { + .init =3D mon_bin_discontig_init, + .get =3D mon_bin_discontig_get, }; =20 -static int mon_bin_mmap(struct file *filp, struct vm_area_struct *vma) +static int mon_bin_mmap_prepare(struct vm_area_desc *desc) { - /* don't do anything here: "fault" will set up page table entries */ - vma->vm_ops =3D &mon_bin_vm_ops; + const struct file *filp =3D desc->file; =20 - if (vma->vm_flags & VM_WRITE) + if (vma_desc_test(desc, VMA_WRITE_BIT)) return -EPERM; =20 - vm_flags_mod(vma, VM_DONTEXPAND | VM_DONTDUMP, VM_MAYWRITE); - vma->vm_private_data =3D filp->private_data; - mon_bin_vma_open(vma); + desc->vm_ops =3D &mon_bin_vm_ops; + vma_desc_clear_flags(desc, VMA_MAYWRITE_BIT); + vma_desc_set_flags(desc, VMA_DONTEXPAND_BIT, VMA_DONTDUMP_BIT); + desc->private_data =3D filp->private_data; + + mmap_action_map_discontig_kernel_pages(desc, NULL, &mon_discontig_ops); return 0; } =20 @@ -1298,7 +1322,7 @@ static const struct file_operations mon_fops_binary = =3D { .compat_ioctl =3D mon_bin_compat_ioctl, #endif .release =3D mon_bin_release, - .mmap =3D mon_bin_mmap, + .mmap_prepare =3D mon_bin_mmap_prepare, }; =20 static int mon_bin_wait_event(struct file *file, struct mon_reader_bin *rp) --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 93F3C3A1A38; Mon, 14 Sep 2026 15:04:32 +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=1789398274; cv=none; b=KF8GTCyqD7DRPglYuCijIxkbJjHlbc+DTq99Fsm/vWEcLQkY7APKd/aS//9HM+AnZ6pGwgbfyQTyhT9KbjAuErV2/Wb67NV0X58aAyFEPOygX2MKhfSrYh9VUvV+1fLztbibq5av/X6dmQDIwRP/NJo13u5bQUns7ZzjDgOgJ8c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398274; c=relaxed/simple; bh=t2zMqz7GwrO9LwCoKVbfTLpQhoUUcOpzKx1NKvIhX3o=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-11-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=10306; i=ljs@kernel.org; h=from:subject:message-id; bh=t2zMqz7GwrO9LwCoKVbfTLpQhoUUcOpzKx1NKvIhX3o=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK/fe8KnXOfZ5zxzlphrF3bNicr173zyyGubnX5P4 T/eoqbpHaUsDGJcDLJiiizPv4jvDxIJm9d5wd8NZg4rE8gQBi5OAZjIlSBGhvvVZwMXmSeUcNem P4lR6n2RszChb++GcjXufWaufmH3ORl+MTf3Z8Z3n1hzjqk87pPjG8F1b7a0OS588sU0auZ/iYN 1HAA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 In cases which map chip memory from vmalloc()'d ranges, the hfi1 infiniband drivers currently installs a fault handler, and then smuggles the kernel virtual address of this range in vma->vm_pgoff. This is exposing KASLR-sensitive internal kernel state in the VMA, and is entirely unnecessary. Instead, use remap_vmalloc_range() to remap the VMA to the span, and eliminate the fault handler altogether. remap_vmalloc_range() checks that the VMA does not extend beyond the vmalloc area, and the driver already requires the VMA to exactly match the span of the memory being mapped, so this has no impact. The memory is all preallocated so not having a fault handler has no impact either, other than pre-mapping the ranges which is beneficial. We also remove the VM_IO flag as it's not appropriate here, and the VM_DONTEXPAND flag as remap_vmalloc_range() will set it (and also mark the range correctly as a mixed map). We also update the vmalloc paths to place the virtual kernel address in memvirt, rather than overloading the physical address memaddr. We predicate the vmalloc handling on the vmalloc flag before we check memvirt for the virtual address-derived PFN remap path, so this works fine. remap_vmalloc_range() requires that the vmalloc()'d areas were all allocated using vmalloc_user() - each of cq->comps, uctxt->subctxt_rcvegrbuf, uctxt->subctxt_rcvhdr_base, uctxt->subctxt_uregbase and dd->events were allocated this way, so that requirement is satisfied. We also remove VM_IO and VM_DONTEXPAND from the STATUS command, as these are both set on remap. Finally, we remove VM_DONTEXPAND from the PIO_BUFS, PIO_BUFS_SOP and UREGS commands, as these are also all set on remap. PIO_CRED retains it, as dma_mmap_coherent() may map via vm_insert_page() on the IOMMU-DMA path, which sets only VM_MIXEDMAP. The RCV_HDRQ, RCV_EGRBUF and RTAIL commands also map via dma_mmap_coherent() and never set VM_DONTEXPAND, so set it for them for the same reason. Note that we retain expected behaviour throughout - the vmalloc remapped ranges set VM_MIXEDMAP | VM_DONTDUMP | VM_DONTEXPAND for each range. VM_IO was never appropriate as the ranges are explicitly not MMIO, and the reference to the v3.7 VM_RESERVED semantics map on to VM_MIXEDMAP | VM_DONTDUMP | VM_DONTEXPAND correctly - no core dump, unmergeable, no normal vm page for purposes of reclaim/migration/etc. There is a change in behaviour in that pages mapped using remap_vmalloc_range() will now have normal GUP-able pages, however this should have no impact as there is no reason not to allow this. Signed-off-by: Lorenzo Stoakes (ARM) --- drivers/infiniband/hw/hfi1/file_ops.c | 83 +++++++++++--------------------= ---- 1 file changed, 25 insertions(+), 58 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/= hfi1/file_ops.c index dc548e6802e2..b02d1f1dbb27 100644 --- a/drivers/infiniband/hw/hfi1/file_ops.c +++ b/drivers/infiniband/hw/hfi1/file_ops.c @@ -70,7 +70,6 @@ static int set_ctxt_pkey(struct hfi1_ctxtdata *uctxt, uns= igned long arg); static int ctxt_reset(struct hfi1_ctxtdata *uctxt); static int manage_rcvq(struct hfi1_ctxtdata *uctxt, u16 subctxt, unsigned long arg); -static vm_fault_t vma_fault(struct vm_fault *vmf); static long hfi1_file_ioctl(struct file *fp, unsigned int cmd, unsigned long arg); =20 @@ -85,10 +84,6 @@ static const struct file_operations hfi1_file_ops =3D { .llseek =3D noop_llseek, }; =20 -static const struct vm_operations_struct vm_ops =3D { - .fault =3D vma_fault, -}; - /* * Types of memories mapped into user processes' space */ @@ -304,13 +299,13 @@ static ssize_t hfi1_write_iter(struct kiocb *kiocb, s= truct iov_iter *from) return reqs; } =20 -static inline void mmap_cdbg(u16 ctxt, u8 subctxt, u8 type, u8 mapio, u8 v= mf, +static inline void mmap_cdbg(u16 ctxt, u8 subctxt, u8 type, u8 mapio, u8 i= s_vmalloc, u64 memaddr, void *memvirt, dma_addr_t memdma, ssize_t memlen, struct vm_area_struct *vma) { hfi1_cdbg(PROC, - "%u:%u type:%u io/vf/dma:%d/%d/%d, addr:0x%llx, len:%lu(%lu), flags:0x= %lx", - ctxt, subctxt, type, mapio, vmf, !!memdma, + "%u:%u type:%u io/vmalloc/dma:%d/%d/%d, addr:0x%llx, len:%lu(%lu), fla= gs:0x%lx", + ctxt, subctxt, type, mapio, is_vmalloc, !!memdma, memaddr ?: (u64)memvirt, memlen, vma->vm_end - vma->vm_start, vma->vm_flags); } @@ -325,7 +320,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_ar= ea_struct *vma) memaddr =3D 0; void *memvirt =3D NULL; dma_addr_t memdma =3D 0; - u8 subctxt, mapio =3D 0, vmf =3D 0, type; + u8 subctxt, mapio =3D 0, is_vmalloc =3D 0, type; ssize_t memlen =3D 0; int ret =3D 0; u16 ctxt; @@ -347,7 +342,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_ar= ea_struct *vma) /* * vm_pgoff is used as a buffer selector cookie. Always mmap from * the beginning. - */=20 + */ vma->vm_pgoff =3D 0; flags =3D vma->vm_flags; =20 @@ -366,7 +361,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_ar= ea_struct *vma) */ memlen =3D PAGE_ALIGN(uctxt->sc->credits * PIO_BLOCK_SIZE); flags &=3D ~VM_MAYREAD; - flags |=3D VM_DONTCOPY | VM_DONTEXPAND; + flags |=3D VM_DONTCOPY; vma->vm_page_prot =3D pgprot_writecombine(vma->vm_page_prot); mapio =3D 1; break; @@ -401,6 +396,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_ar= ea_struct *vma) memlen =3D rcvhdrq_size(uctxt); memvirt =3D uctxt->rcvhdrq; memdma =3D uctxt->rcvhdrq_dma; + flags |=3D VM_DONTEXPAND; break; case RCV_EGRBUF: { unsigned long vm_start_save; @@ -422,7 +418,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_ar= ea_struct *vma) ret =3D -EPERM; goto done; } - vm_flags_clear(vma, VM_MAYWRITE); + vm_flags_mod(vma, VM_DONTEXPAND, VM_MAYWRITE); /* * Mmap multiple separate allocations into a single vma. From * here, dma_mmap_coherent() calls dma_direct_mmap(), which @@ -438,7 +434,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_ar= ea_struct *vma) memvirt =3D uctxt->egrbufs.buffers[i].addr; memdma =3D uctxt->egrbufs.buffers[i].dma; vma->vm_end +=3D memlen; - mmap_cdbg(ctxt, subctxt, type, mapio, vmf, memaddr, + mmap_cdbg(ctxt, subctxt, type, mapio, is_vmalloc, memaddr, memvirt, memdma, memlen, vma); ret =3D dma_mmap_coherent(&dd->pcidev->dev, vma, memvirt, memdma, memlen); @@ -467,7 +463,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_ar= ea_struct *vma) * user registers. */ memlen =3D PAGE_SIZE; - flags |=3D VM_DONTCOPY | VM_DONTEXPAND; + flags |=3D VM_DONTCOPY; vma->vm_page_prot =3D pgprot_noncached(vma->vm_page_prot); mapio =3D 1; break; @@ -476,15 +472,10 @@ static int hfi1_file_mmap(struct file *fp, struct vm_= area_struct *vma) * Use the page where this context's flags are. User level * knows where it's own bitmap is within the page. */ - memaddr =3D (unsigned long) - (dd->events + uctxt_offset(uctxt)) & PAGE_MASK; + memvirt =3D dd->events + uctxt_offset(uctxt); + memvirt =3D (void *)(((uintptr_t)memvirt) & PAGE_MASK); memlen =3D PAGE_SIZE; - /* - * v3.7 removes VM_RESERVED but the effect is kept by - * using VM_IO. - */ - flags |=3D VM_IO | VM_DONTEXPAND; - vmf =3D 1; + is_vmalloc =3D 1; break; case STATUS: if (flags & VM_WRITE) { @@ -493,7 +484,6 @@ static int hfi1_file_mmap(struct file *fp, struct vm_ar= ea_struct *vma) } memaddr =3D kvirt_to_phys((void *)dd->status); memlen =3D PAGE_SIZE; - flags |=3D VM_IO | VM_DONTEXPAND; break; case RTAIL: if (!HFI1_CAP_IS_USET(DMA_RTAIL)) { @@ -512,25 +502,23 @@ static int hfi1_file_mmap(struct file *fp, struct vm_= area_struct *vma) memvirt =3D (void *)hfi1_rcvhdrtail_kvaddr(uctxt); memdma =3D uctxt->rcvhdrqtailaddr_dma; flags &=3D ~VM_MAYWRITE; + flags |=3D VM_DONTEXPAND; break; case SUBCTXT_UREGS: - memaddr =3D (u64)uctxt->subctxt_uregbase; + memvirt =3D uctxt->subctxt_uregbase; memlen =3D PAGE_SIZE; - flags |=3D VM_IO | VM_DONTEXPAND; - vmf =3D 1; + is_vmalloc =3D 1; break; case SUBCTXT_RCV_HDRQ: - memaddr =3D (u64)uctxt->subctxt_rcvhdr_base; + memvirt =3D uctxt->subctxt_rcvhdr_base; memlen =3D rcvhdrq_size(uctxt) * uctxt->subctxt_cnt; - flags |=3D VM_IO | VM_DONTEXPAND; - vmf =3D 1; + is_vmalloc =3D 1; break; case SUBCTXT_EGRBUF: - memaddr =3D (u64)uctxt->subctxt_rcvegrbuf; + memvirt =3D uctxt->subctxt_rcvegrbuf; memlen =3D uctxt->egrbufs.size * uctxt->subctxt_cnt; - flags |=3D VM_IO | VM_DONTEXPAND; flags &=3D ~VM_MAYWRITE; - vmf =3D 1; + is_vmalloc =3D 1; break; case SDMA_COMP: { struct hfi1_user_sdma_comp_q *cq =3D fd->cq; @@ -539,10 +527,9 @@ static int hfi1_file_mmap(struct file *fp, struct vm_a= rea_struct *vma) ret =3D -EFAULT; goto done; } - memaddr =3D (u64)cq->comps; + memvirt =3D cq->comps; memlen =3D PAGE_ALIGN(sizeof(*cq->comps) * cq->nentries); - flags |=3D VM_IO | VM_DONTEXPAND; - vmf =3D 1; + is_vmalloc =3D 1; break; } default: @@ -559,12 +546,10 @@ static int hfi1_file_mmap(struct file *fp, struct vm_= area_struct *vma) } =20 vm_flags_reset(vma, flags); - mmap_cdbg(ctxt, subctxt, type, mapio, vmf, memaddr, memvirt, memdma,=20 + mmap_cdbg(ctxt, subctxt, type, mapio, is_vmalloc, memaddr, memvirt, memdm= a, memlen, vma); - if (vmf) { - vma->vm_pgoff =3D PFN_DOWN(memaddr); - vma->vm_ops =3D &vm_ops; - ret =3D 0; + if (is_vmalloc) { + ret =3D remap_vmalloc_range(vma, memvirt, 0); } else if (memdma) { ret =3D dma_mmap_coherent(&dd->pcidev->dev, vma, memvirt, memdma, memlen); @@ -588,24 +573,6 @@ static int hfi1_file_mmap(struct file *fp, struct vm_a= rea_struct *vma) return ret; } =20 -/* - * Local (non-chip) user memory is not mapped right away but as it is - * accessed by the user-level code. - */ -static vm_fault_t vma_fault(struct vm_fault *vmf) -{ - struct page *page; - - page =3D vmalloc_to_page((void *)(vmf->pgoff << PAGE_SHIFT)); - if (!page) - return VM_FAULT_SIGBUS; - - get_page(page); - vmf->page =3D page; - - return 0; -} - static __poll_t hfi1_poll(struct file *fp, struct poll_table_struct *pt) { struct hfi1_ctxtdata *uctxt; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 3D61448594F; Mon, 14 Sep 2026 15:05:00 +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=1789398302; cv=none; b=X+mQ9xFMOcClVY8QWTiH6BR4flC6VVoiDpDrNNQOHBx/mICwE/mcAoTbPCrF+ndxFHzdRoVcKF8bcE5BJpM8tlkBMtPEZjFe76ps4SxWZY0kLiBlcnl+mVYCvM+crsTCU10y16/I0lBeb2PLI4b2HNyjMRalHRgI/Le5orJ7t1s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398302; c=relaxed/simple; bh=aNFeiTnbUkQbxAr7iS7c1JWEd9CfcPtAZlIAhlnNHxY=; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-12-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=1880; i=ljs@kernel.org; h=from:subject:message-id; bh=aNFeiTnbUkQbxAr7iS7c1JWEd9CfcPtAZlIAhlnNHxY=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK/P/j95F9+ty7p/527K+tW0JfG+DEf4P32mmh+dv 6vUHwd+7ihlYRDjYpAVU2R5/kV8f5BI2LzOC/5uMHNYmUCGMHBxCsBELpoxMkzsPHubz6Sm1YvB RI91mn2IAIPb5HWT9rbvD6zmt58vpsnwm4Wl10N5h3NGzfr/023uJ+zx2VNjEXE2/8at8MbXvpf zWQA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 The policy file has no write method and is exposed read-only (S_IRUGO in selinux_files[]), yet sel_open_policy() performs no open mode check, so a CAP_DAC_OVERRIDE caller can open it O_RDWR. Reject FMODE_WRITE at open, as kernfs does. The file can then never be mapped with FMODE_WRITE, so do_mmap() always clears VM_MAYWRITE and VM_SHARED for MAP_SHARED mappings and the VM_SHARED check in sel_mmap_policy() cannot be reached. Remove it. This also stops sel_mmap_policy() clearing VM_MAYWRITE on a mapping that is neither a PFN map nor a mixed map, ahead of the core enforcing that only such mappings may do so. Acked-by: Stephen Smalley Reviewed-by: Jann Horn Signed-off-by: Lorenzo Stoakes (ARM) Acked-by: Paul Moore --- security/selinux/selinuxfs.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index c7d91476971c..545a6f89f9e7 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -340,6 +340,9 @@ static int sel_open_policy(struct inode *inode, struct = file *filp) struct policy_load_memory *plm =3D NULL; int rc; =20 + if (filp->f_mode & FMODE_WRITE) + return -EACCES; + rc =3D avc_has_perm(current_sid(), SECINITSID_SECURITY, SECCLASS_SECURITY, SECURITY__READ_POLICY, NULL); if (rc) @@ -424,14 +427,6 @@ static const struct vm_operations_struct sel_mmap_poli= cy_ops =3D { =20 static int sel_mmap_policy(struct file *filp, struct vm_area_struct *vma) { - if (vma->vm_flags & VM_SHARED) { - /* do not allow mprotect to make mapping writable */ - vm_flags_clear(vma, VM_MAYWRITE); - - if (vma->vm_flags & VM_WRITE) - return -EACCES; - } - vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP); vma->vm_ops =3D &sel_mmap_policy_ops; =20 --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 ACD7948594F; Mon, 14 Sep 2026 15:05:27 +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=1789398329; cv=none; b=MatgjeCOZyFYMPPjKOOx/GRTHAuPiyJRxwoMK5YXAOjAP+oaAroMnyGHH9BsQEA1lvsy6yITGF+MejHNn99HcwFhYguej+QsEikg1NupqYShxs3DIYw4MSbkK+IUgC7a5oOG5owNBOuDtJ8pbSwbcla8bQXdbmecF259LmbgyKs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398329; c=relaxed/simple; bh=BufAYcKoxP4rPy82Onp5UAmN13VcupWKa3H7JCJQDTQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=D7n88kMTQy/Z6nZi9eQ0fQUYMq+2RYJocBaRx5P+bWLKLwDXFaXzmlBhD3ItZm/LyVSg3+fZCde0ofyAhyjS7zaUWktJWoPE8vmx65z3OMjwH/OmHBT8/8kIcwaUMYBm7/WPlNj41fVgSCPTdrGma/p9JqSHphCPJmxOIN1GH94= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UD5PNoW4; 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="UD5PNoW4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FB141F00898; Mon, 14 Sep 2026 15:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398327; bh=Ht1E3XYrT6zNGxe7BXRz6LPnDrSfYBDlq1F1i7I+270=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=UD5PNoW4R8TJPc+RDDL3nG5Y1YQvYyAiYnzBxh0zYH0b/+Bt5gLTsU+RvcepWwXl9 vGmu1XkGwSr/gCqlhbzjULKWUtKhSJS+hFruG4mLMnloiAA6CrcyK4NubUfb7quSnr +pT32wgyKeo9qghsHa0mPlmJ+DdQ8vYcXEeeirDOZzVJ+ANI96vDPfw5Z5i+P3ACOy G+NeTFtPHqQafdV1FNH9Ta2sVqxe12g43axrM9WI2nsu7Wx37vTmyVTj3S1gwIDfRa iqt6wTjJEaikYYmfVMDWTwtWfyRMP4TamLvXWLtw6mN/f+6l8nhmh8/DFWULAokJYP /2/OVRz0eRFSg== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:33 +0100 Subject: [PATCH v2 13/40] ALSA: pcm: use vm_insert_page() to map PCM status page Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-13-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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)" , Takashi Iwai X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=2769; i=ljs@kernel.org; h=from:subject:message-id; bh=BufAYcKoxP4rPy82Onp5UAmN13VcupWKa3H7JCJQDTQ=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK+vLojmLzf1vhywWW+2TchqpeLCfL9Hf29VfFic7 +R2i7O1o5SFQYyLQVZMkeX5F/H9QSJh8zov+LvBzGFlAhnCwMUpABPhf87wV+ydcNxHCf/98y12 rlP/3Gru9ig8qzvq2nTh51v2lIhrzmP4Z5H1ui/cUeppRvdZIXWXH7ESXP+UXt/fzuhh6JL+ZNE qVgA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 There's no need to keep a fault handler around for this, instead map on mmap. While we're here, rename area to vma to be consistent. This correctly makes the mapping a mixed map mapping. This works towards establishing the invariant that only PFN mapped or mixed map mappings may clear the VM_MAYWRITE flag. The status page mapping clears VM_MAYWRITE, so it must be kernel-owned; the control page mapping remains writable and is left fault-based. The assumption is made that the struct pcm_mmap_status structure is at most a page in size, which is asserted as a build bug. This is safe to assume, as the size of the structure is 56 bytes at most. Acked-by: Takashi Iwai Signed-off-by: Lorenzo Stoakes (ARM) --- sound/core/pcm_native.c | 38 +++++++++++++------------------------- 1 file changed, 13 insertions(+), 25 deletions(-) diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 62324282fcae..c98fb3df14f3 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -3760,39 +3760,27 @@ static __poll_t snd_pcm_poll(struct file *file, pol= l_table *wait) /* * mmap status record */ -static vm_fault_t snd_pcm_mmap_status_fault(struct vm_fault *vmf) +static int snd_pcm_mmap_status(struct snd_pcm_substream *substream, struct= file *file, + struct vm_area_struct *vma) { - struct snd_pcm_substream *substream =3D vmf->vma->vm_private_data; + const unsigned long size =3D vma->vm_end - vma->vm_start; struct snd_pcm_runtime *runtime; -=09 - if (substream =3D=3D NULL) - return VM_FAULT_SIGBUS; - runtime =3D substream->runtime; - vmf->page =3D virt_to_page(runtime->status); - get_page(vmf->page); - return 0; -} + struct page *page; =20 -static const struct vm_operations_struct snd_pcm_vm_ops_status =3D -{ - .fault =3D snd_pcm_mmap_status_fault, -}; + BUILD_BUG_ON(sizeof(struct snd_pcm_mmap_status) > PAGE_SIZE); =20 -static int snd_pcm_mmap_status(struct snd_pcm_substream *substream, struct= file *file, - struct vm_area_struct *area) -{ - long size; - if (!(area->vm_flags & VM_READ)) + if (!(vma->vm_flags & VM_READ)) return -EINVAL; - size =3D area->vm_end - area->vm_start; - if (size !=3D PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status))) + if (size !=3D PAGE_SIZE) return -EINVAL; - area->vm_ops =3D &snd_pcm_vm_ops_status; - area->vm_private_data =3D substream; - vm_flags_mod(area, VM_DONTEXPAND | VM_DONTDUMP, + + vm_flags_mod(vma, VM_DONTEXPAND | VM_DONTDUMP, VM_WRITE | VM_MAYWRITE); + vma->vm_page_prot =3D vm_get_page_prot(vma->vm_flags); =20 - return 0; + runtime =3D substream->runtime; + page =3D virt_to_page(runtime->status); + return vm_insert_page(vma, vma->vm_start, page); } =20 /* --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 2EF96496D2B; Mon, 14 Sep 2026 15:05:56 +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=1789398358; cv=none; b=FNnOjI+9XCArDhYSmlMS0adF93j9iML7WPZFs7mtiQdYSNm6m5sjSLPrBUd55s037DTMUGTG+eIORwNmeZMIB0R0gq1CCC3sGFIHbL9MdqAB66Zoa1HYMBQ9QmIZmtP6MLdFYv2FLGUS78b1Mx9Tm5TKy+fEJRzY4nGZTyUJwtg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398358; c=relaxed/simple; bh=fdJtBNQadhST13A5/QqOS4hxZn92kbQM6NW+rZ1tlXQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=pfOTIGWScAw0oxKO/byozsEfabaCNflT+LiGZpLf5kDs2zvQdKm5fXL3ZeEtG17yQnKjEwGaBj//3a5p9XSnKO5HdLy4T2TVWof4H5b69zS26Inn4uQc1SWxuGGK2bZ/PlXjbefl9cf/Whm4446VCbQsNM5mn/207ZSjYWfNtxU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=o2HJqMb6; 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="o2HJqMb6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB3931F000FF; Mon, 14 Sep 2026 15:05:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398355; bh=8M2KGQ/Rdd7X1qvg4n3rsyBcsIsT/58MPgOQgnVvrcw=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=o2HJqMb6UivQC8UjJz7ubcSKeKsWvNsYPgzZqd/tAzyG8Dn3/gtoL9ZCUQFx6WgF5 C9FGWntSayxAU6eUnP7iATrD3fpH0wmnv07IPIwm7ET7skvb6y7buHIWqYX1zVqbsY 4ESb7Zg7b0mDXlnVpRhJsurFsSXv1NBjg+7iB6ZaPe7XOp9Php+Dg18jhd1evb7gJU CHyw4RFTUdSF0/PGWpr3aXyrmm4xVa0kWF01jb0RWCLOxy9hiME7RTUInidX9L4jOe cNIlWnTtXBkXsobT/LJM6HktktPI1sPsJ2vA4g1QBizqOk85CxnSmKSW6TzXj4iycw DojmzJGshXsvw== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:34 +0100 Subject: [PATCH v2 14/40] bpf: arena: mark arena_map_mmap() mappings VM_MIXEDMAP Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-14-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2077; i=ljs@kernel.org; h=from:subject:message-id; bh=fdJtBNQadhST13A5/QqOS4hxZn92kbQM6NW+rZ1tlXQ=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcK8XkD7BpLs7ZpLngpk9lj4boqXZJ/v8+Wqbu+pyj o14Atv8jlIWBjEuBlkxRZbnX8T3B4mEzeu84O8GM4eVCWQIAxenAExkcyAjw48Ps/tvhbe/NZP2 3JZfdCLk6zaVbjv1hAN7l5c0rpyQL8zwz7Ji1sQNNbuZZzhoZ6aU7f3OXaQdavXyt4CuQNf82QE TmQA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 The bpf_map->ops->map_mmap callback invoked by bpf_map_mmap() can be set to one of ringbuf_map_mmap_kern(), ringbuf_map_mmap_user(), array_map_mmap() or arena_map_mmap(). It is convention in mm to mark mappings whose pages the kernel manages itself with VM_MIXEDMAP, so the core mm knows not to treat them as ordinary page cache or anonymous memory. The map_mmap callbacks ringbuf_map_mmap_kern() and ringbuf_map_mmap_user() use remap_vmalloc_range(), which ultimately invokes vm_insert_page() and so marks the ranges VM_MIXEDMAP, and array_map_mmap() sets VM_MIXEDMAP explicitly. However, the exception to this is arena_map_mmap(), which doesn't set the flag. This patch corrects this and updates the comment to reflect it. The pages are refcounted and vm_normal_page() finds them regardless of the flag, and VM_DONTEXPAND remains set (marking the memory as VM_SPECIAL and thus unmergeable). The one effect is that NUMA balancing now skips these VMAs, as it already does for the other bpf map mappings, which is the reason array_map_mmap() gives for setting the flag. The intent of this patch is to be able to establish the invariant that only PFN-mapped or mixed map ranges may clear the VM_MAYWRITE flag, as is done in bpf_map_mmap(). Signed-off-by: Lorenzo Stoakes (ARM) Reviewed-by: Emil Tsalapatis --- kernel/bpf/arena.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c index 7b6847200b43..b69fe5e34339 100644 --- a/kernel/bpf/arena.c +++ b/kernel/bpf/arena.c @@ -620,8 +620,9 @@ static int arena_map_mmap(struct bpf_map *map, struct v= m_area_struct *vma) * clears VM_MAYEXEC. Set VM_DONTEXPAND to avoid potential change * of user_vm_start. Set VM_DONTCOPY to prevent arena VMA from * being copied into the child process on fork. + * This is a kernel page so set VM_MIXEDMAP. */ - vm_flags_set(vma, VM_DONTEXPAND | VM_DONTCOPY); + vm_flags_set(vma, VM_MIXEDMAP | VM_DONTEXPAND | VM_DONTCOPY); vma->vm_ops =3D &arena_vm_ops; return 0; } --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 07328496D54; Mon, 14 Sep 2026 15:06:22 +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=1789398384; cv=none; b=tj4j33eorE15v/5Gc8HZfLG9AsjLesla/hLRPWk830+51HHmSmel2cWNPWjuuez6q2rgQsedjOXJ5HcRJnrlHSJ8Ml4a+F+f6vYCjUSsZHbU0Z+Q68OHsEBjEcbW7v1oWqAILaAfmtGgh8TKUXcKrB8tUSK0kngEkIvT6xqgvXQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398384; c=relaxed/simple; bh=YkBI9YfuiRUNJqQZzdNQ3yvqq1XQeKFLWKyJwcARZII=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=JPDksaVZ9asZGLE18AcUz6tWQtzEyP9fJEZJjSJJGZzSRRV9awQJ3LWS/Yz2uVQEa2GrGgtcHlLsDM6jSx0S9uHKTybNIaXOgO7NJPEMhXDm5ZTaefvQKzlPezKX27yyQFaGr1W9BUFBGrwYP7Ca61Y+jpIHM9EtyR0N5980gA4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XONMabZx; 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="XONMabZx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F73D1F00893; Mon, 14 Sep 2026 15:05:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398382; bh=960UTemXLlYbejvF++nDfw4hlZnQCzP1Mhoxnlt8Uqc=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=XONMabZx9a2tMH4C2B8NLveFpQiwpsb9v/absrNfv7MTntkbuo8zaX269YxgARiRW Px/otvDFyxGLFNwGAiVTkFUVvE8SDw8kNQGm+XBLXkJuYHnRNCCMxneuB6eXBil2W1 CcWuu3UAsYQci0UW1VkyyLKK5Mie8vOwgoDrbKDZHI+tMSxDYzimAYyuEpV4/84ad7 vk2Ao2o/VGO5U5fQH+AK2T60rxC/fvRLY9K2gTjsnb75/nU2WpKtiDwUnkvN5TSth/ TY5FQ5xVgK7Hj3X1cfNFd+sL/ccxjs54mQO0NS/b9l5BtrdTD+GlTStU5ozTn7/DkO Ia9bHhdQfYdlQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:35 +0100 Subject: [PATCH v2 15/40] mm/vma: add vma[_flags]_is_kernel_owned() predicates Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-15-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=5411; i=ljs@kernel.org; h=from:subject:message-id; bh=YkBI9YfuiRUNJqQZzdNQ3yvqq1XQeKFLWKyJwcARZII=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG+wsVOSY4w5+8xmjzjHFyWZEPfZ9ns1W+frPlA9N 104y+1PRykLgxgXg6yYIsvzL+L7g0TC5nVe8HeDmcPKBDKEgYtTACayUo2R4e6dd/UV352+6G3Y EHeyNXL5p2U1Nqf2FW/4ep1xzjyBc3cY/gc48Ng8v6G85LnDN9XwxJST1VaLq0WL5/098tvlC6f wVDYA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Rather than referring to VMA flags with uncertain meaning, add a new predicate that explicitly describes what possession of the VMA_PFNMAP_BIT or VMA_MIXEDMAP_BIT flags mean, and then refer to that function for determining VMA mergeability. Either flag means the contents of the mapping are owned by the kernel, usually a driver, rather than by the core mm: the memory may be MMIO, kernel-allocated pages or even ordinary pages the driver maps itself, but the core must not populate, reclaim, migrate, copy-on-write or merge the range on its own initiative. We initially also include VMA_IO_BIT here, as by implication, these must be kernel-owned. (mlock() also sets VMA_IO_BIT transiently on ordinary VMAs while locking them, which is addressed later in this series.) However the intent is to in future remove this, as no mapping should be marked as an I/O mapping without also being marked with VMA_PFNMAP_BIT. This forms the basis of further work intended to improve how we express VMA properties such as this. Also update the VMA userland tests to reflect the change. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 56 +++++++++++++++++++++++++++++++++++++= +++- tools/testing/vma/include/dup.h | 29 ++++++++++++++++++++- 2 files changed, 83 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 2a92193ac6a5..cab29d6e15c1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1612,6 +1612,44 @@ static inline bool vma_is_shared_maywrite(const stru= ct vm_area_struct *vma) return is_shared_maywrite(&vma->flags); } =20 +/** + * vma_flags_is_kernel_owned() - Do the specified VMA flags indicate that = the + * contents of the VMA are owned by the kernel rather than the core mm? + * @flags: The VMA flags to test. + * + * A kernel-owned mapping is one whose contents are established and contro= lled + * by the kernel, typically a driver, rather than by the core mm's fault a= nd + * rmap machinery. + * + * The mapping may be memory-mapped I/O, kernel-allocated pages or ordinary + * pages the owner has chosen to map itself (shmem via a PFN map, for inst= ance). + * + * In all cases the core mm must not populate, reclaim, migrate, copy-on-w= rite + * or merge it of its own accord. + * + * Pages mapped this way are not necessarily reference counted or map coun= ted. + * + * Returns: true if the flags indicate a kernel-owned mapping. + */ +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); +} + +/** + * vma_is_kernel_owned() - Are the contents of @vma owned by the kernel? + * @vma: The VMA to test. + * + * See vma_flags_is_kernel_owned() for a description of this property. + * + * Returns: true if the VMA is kernel-owned. + */ +static inline bool vma_is_kernel_owned(const struct vm_area_struct *vma) +{ + return vma_flags_is_kernel_owned(&vma->flags); +} + /** * vma_flags_can_merge() - Do the specified VMA flags permit the VMA to be * merged with another? @@ -1620,7 +1658,23 @@ static inline bool vma_is_shared_maywrite(const stru= ct vm_area_struct *vma) */ static inline bool vma_flags_can_merge(const vma_flags_t *flags) { - return !vma_flags_test_any_mask(flags, VMA_SPECIAL_FLAGS); + /* + * VMA merging assumes that a VMA's flags and fields completely describe + * its state. + * + * However, kernel-owned mappings may have established state upon mapping + * not embodied in any attribute of the VMA. + * + * Additionally, private (CoW) PFN maps encode the source PFN of the + * range in vma->vm_pgoff, which may otherwise cause spurious merges. + */ + if (vma_flags_is_kernel_owned(flags)) + return false; + /* VMA explicitly marked as being unmergeable. */ + if (vma_flags_test(flags, VMA_DONTEXPAND_BIT)) + return false; + + return true; } =20 /** diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/du= p.h index 1d5f6b3cbd21..9205ebf31ce7 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -1665,7 +1665,34 @@ static inline bool file_is_dev_zero(const struct fil= e *file) return file && file->f_op =3D=3D &zero_fops; } =20 +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); +} + +static inline bool vma_is_kernel_owned(const struct vm_area_struct *vma) +{ + return vma_flags_is_kernel_owned(&vma->flags); +} + static inline bool vma_flags_can_merge(const vma_flags_t *flags) { - return !vma_flags_test_any_mask(flags, VMA_SPECIAL_FLAGS); + /* + * VMA merging assumes that the properties of a VMA completely describe + * the properties of that VMA. + * + * However, kernel-owned mappings may have established state upon mapping + * not embodied in any attribute of the VMA. + * + * Additionally, PFN maps encode the source PFN of the range in + * vma->vm_pgoff, which may otherwise cause spurious merges. + */ + if (vma_flags_is_kernel_owned(flags)) + return false; + /* VMA explicitly marked as being unmergeable. */ + if (vma_flags_test(flags, VMA_DONTEXPAND_BIT)) + return false; + + return true; } --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 5AD0648EC7D; Mon, 14 Sep 2026 15:06:50 +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=1789398412; cv=none; b=LaoiU0SkFcgnrZ0C8pZDwdjGS/y49WEIU/F6RNN4KvKjU6criydR2UVjAgDOi0MOsbWWSfmVt1ZDZlr2+Rl00HEO72szkB5Ycj+X0etm24V82yLwQZP8cf4BgK1i+6NB4AdgNlMc1hPKI9EoBu536+qXR5Q1fjMyUpeffpDnFuY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398412; c=relaxed/simple; bh=VBJ5n0AzlLNSnyXutKBzqVELhsd1soVPc5lqklQgPTI=; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-16-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2245; i=ljs@kernel.org; h=from:subject:message-id; bh=VBJ5n0AzlLNSnyXutKBzqVELhsd1soVPc5lqklQgPTI=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG/omrjXccJEyb0TfbbptCkvLPzj4G75bEaixMn/G 3OqZFludZSyMIhxMciKKbI8/yK+P0gkbF7nBX83mDmsTCBDGLg4BWAiIYoM/2xSji3htFhzhp9B 9l3a1uSpD7xP3JHol/u9c5Kk5CyxxF0M/0w91VW4xfc9KuMsTZHclZn8MIPNMnunxI4v15MmyIt VsgMA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 For ordinary files the only way the VMA_MAYWRITE_BIT flag is cleared is if the underlying file is itself read-only. This means that mprotect() cannot mark a shared mapping of a read-only file as read/write, as doing so would violate the read only attribute, and permit writes. In general, we do not want file systems to be able to do this for read/write files. Doing so would violate fundamental user expectation of file attributes and likely break userspace. However, drivers pose a tricky problem here - the /dev/xxx file may be read/write but provide access to a resource which is fundamentally read-only. Therefore we must allow drivers to be able to clear VMA_MAYWRITE_BIT. To achieve both of these things, restrict this ability to kernel-owned mappings as identified by vma_flags_is_kernel_owned(). This constrains this ability to drivers which own the mapping's contents, whether memory-mapped I/O, kernel-allocated pages, or ordinary pages they map themselves, and so define its semantics. Every in-tree mmap hook which clears VMA_MAYWRITE_BIT, some twenty sites across drivers, filesystems and bpf, establishes a kernel-owned mapping, with usbmon and the ALSA PCM status page converted earlier in this series to do so. Note that drivers may, if they do not gate on VMA_SHARED_BIT, be able to disable MAP_PRIVATE-file-backed mapping CoW semantics. This is perhaps not always intended, but we retain this capacity to maintain existing behaviour. As all drivers which clear VMA_MAYWRITE_BIT establish kernel-owned mappings, no functional change is intended. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/vma.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/vma.c b/mm/vma.c index 2648fb0e1995..d71ec51255b1 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2795,6 +2795,11 @@ static int mmap_validate(unsigned long prev_start, if (WARN_ON_ONCE(!was_maywrite && is_maywrite)) return -EINVAL; =20 + /* Only kernel-owned mappings may clear VMA_MAYWRITE_BIT. */ + if (!vma_flags_is_kernel_owned(curr_flags) && + WARN_ON_ONCE(was_maywrite && !is_maywrite)) + return -EINVAL; + return mmap_validate_vma_flags(curr_flags); } =20 --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 DB8CD49F114; Mon, 14 Sep 2026 15:07:18 +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=1789398441; cv=none; b=tmU06hx5rXNE9QrnDsFhIfp/BsEn790QUGw/mddbnHRTSkNfCs5b/OqbaFrkzeG8Fe3KjhrrLdTfTuC9xvK8SWeB698v/Epb2Sbetlc0n71Bm7jbPrVXZcfAmjuxiDz1JiJ8AfkKkvuVlY92V/MKcgEDCHPpE7Fj/b1/qpDohUc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398441; c=relaxed/simple; bh=UgNv55sIQWtamT8dsOv1+a458wZvL5aAIbvGVpSsXcA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=IQvXWpC5BBWlTsbh2KGh45UUCesmhdYWntpEz1JA5rz2YSj6BwTBW6el80pjOAvXKxP21GuHPjyxgvTvW4HM5tAniVpkEOJU3tsbGwdSdIuMRcUo2j5y/7wAK0CW+J54BDigBT0S74vvoFLVAXR++ozyTaJZsECPHCjZVryy0I0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JP4elXwi; 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="JP4elXwi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 900991F00893; Mon, 14 Sep 2026 15:06:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398437; bh=uXoP7KZkJndcQGjeTZtASZtk39J3Stk4EQblO5zGMq8=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=JP4elXwiAFA0FtwbVJkNWUu4T0Hzo9hzF4qxtFcaZGI2BYyYdJ7emz+yKFI5FfxNH 0cT3grCiQLAEsYrA9SpcqTxYQH9Q4a3S72QM2jhXwMERUNnVU4TEqv7+ODjKLX1vRo yt78e2/7GRJ18TnOwJcTwkytfEF13UQDVzvzQUo0m7DDBUxxiQTcXZzEtoEHTnuzx8 OIXXD+w5mukAKrvguVJb40RZkdv9UXSob5Khh05J4FZEOaDaVTPsjUeprqvPXGLHih dcrtIQoFwJbxwgqJG2d7R7GWAZRzLeleOwml/wW15s5ZmWirPRc81EXEt9jwEys+BS HH5yA6sYVVYZw== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:37 +0100 Subject: [PATCH v2 17/40] mm/vma: add and use vma_[flags]_is_fixed_mapping Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-17-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=5182; i=ljs@kernel.org; h=from:subject:message-id; bh=UgNv55sIQWtamT8dsOv1+a458wZvL5aAIbvGVpSsXcA=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG/4ss6jauPjR1W3XHfeXDyzsi1zaUK7y6omzwY7x qXCcx8Jd5SyMIhxMciKKbI8/yK+P0gkbF7nBX83mDmsTCBDGLg4BWAiAS8YGfb3Fi4wvSL9oEAl 8Et56Paz2xear5/+in/Xl63mtz7IftvOyHDp3AxndUfDwss2HXXlTUw72UUPcK+63vts4rzEy3J /ynkB X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 This determines whether a VMA cannot be expanded or merged because what they mapped was determined to be a set size at mmap time. This typically refers to kernel-owned mappings, however VMA_DONTEXPAND_BIT is not reliably set alongside VMA_PFNMAP_BIT or VMA_MIXEDMAP_BIT, so we must explicitly test for this for now. We also explicitly test for VMA_PFNMAP_BIT as VMA_DONTEXPAND_BIT may not be set for VMA_PFNMAP_BIT's despite the one implying the other. Use this predicate in vma_flags_can_merge() and in check_prep_vma() in the mremap logic testing to see if mremap() can expand the VMA. The criteria for khugepaged and MADV_COLLAPSE eligibility in __thp_vma_allowable_orders() are precisely those for mergeability, so use vma_can_merge() there (with an expanded comment). This obviates the need for the VM_NO_KHUGEPAGED mask, so remove it. Hugetlb VMAs remain excluded from khugepaged as hugetlbfs always sets VMA_DONTEXPAND_BIT. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 39 +++++++++++++++++++++++++++++++++++---- mm/huge_memory.c | 11 +++++++---- mm/mremap.c | 5 ++--- 3 files changed, 44 insertions(+), 11 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index cab29d6e15c1..ca598e5f9715 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -600,9 +600,6 @@ enum { #define VMA_REMAP_FLAGS mk_vma_flags(VMA_IO_BIT, VMA_PFNMAP_BIT, \ VMA_DONTEXPAND_BIT, VMA_DONTDUMP_BIT) =20 -/* This mask prevents VMA from being scanned with khugepaged */ -#define VM_NO_KHUGEPAGED (VM_SPECIAL | VM_HUGETLB) - /* This mask defines which mm->def_flags a process can inherit its parent = */ #define VM_INIT_DEF_MASK VM_NOHUGEPAGE =20 @@ -1650,6 +1647,40 @@ static inline bool vma_is_kernel_owned(const struct = vm_area_struct *vma) return vma_flags_is_kernel_owned(&vma->flags); } =20 +/** + * vma_flags_is_fixed_mapping() - Do the specified VMA flags indicate that= this + * is a fixed mapping that cannot be expanded or merged? + * @flags: The VMA flags to test. + * + * Fixed mappings are those whose size is set at the point of mmap (for + * instance, a kernel-owned mapping of a fixed range of memory), and thus + * cannot be expanded or merged. + * + * Returns: true if the flags indicate a fixed mapping. + */ +static inline bool vma_flags_is_fixed_mapping(const vma_flags_t *flags) +{ + /* + * VMA_PFNMAP_BIT should imply VMA_DONTEXPAND_BIT, but some callers set + * only the former. + */ + return vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_DONTEXPAND_BIT); +} + +/** + * vma_is_fixed_mapping() - Is this VMA a fixed mapping that cannot be + * expanded or merged? + * @vma: The VMA to test. + * + * See vma_flags_is_fixed_mapping() for a description of this property. + * + * Returns: true if the VMA maps a fixed mapping. + */ +static inline bool vma_is_fixed_mapping(const struct vm_area_struct *vma) +{ + return vma_flags_is_fixed_mapping(&vma->flags); +} + /** * vma_flags_can_merge() - Do the specified VMA flags permit the VMA to be * merged with another? @@ -1671,7 +1702,7 @@ static inline bool vma_flags_can_merge(const vma_flag= s_t *flags) if (vma_flags_is_kernel_owned(flags)) return false; /* VMA explicitly marked as being unmergeable. */ - if (vma_flags_test(flags, VMA_DONTEXPAND_BIT)) + if (vma_flags_is_fixed_mapping(flags)) return false; =20 return true; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 4cd917f77f3f..4d0acd9a1099 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -212,11 +212,14 @@ unsigned long __thp_vma_allowable_orders(struct vm_ar= ea_struct *vma, return in_pf ? orders : 0; =20 /* - * khugepaged special VMA and hugetlb VMA. - * Must be checked after dax since some dax mappings may have - * VM_MIXEDMAP set. + * khugepaged moves data from VMAs once collapsed, after they have been + * faulted in, relying on refaulting for file-backed memory. + * + * Kernel-owned mappings cannot be reliably reconstructed from page + * faults, and fixed mappings (including hugetlb) may not be marked as + * kernel-owned - precisely the mappings which cannot be merged. */ - if (!in_pf && !smaps && (vm_flags & VM_NO_KHUGEPAGED)) + if (!in_pf && !smaps && !vma_can_merge(vma)) return 0; =20 /* diff --git a/mm/mremap.c b/mm/mremap.c index 7c368440fafe..ed19b47c2caf 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -1788,8 +1788,7 @@ static int check_prep_vma(struct vma_remap_struct *vr= m) return -EINVAL; } =20 - if ((vrm->flags & MREMAP_DONTUNMAP) && - vma_test_any(vma, VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT)) + if ((vrm->flags & MREMAP_DONTUNMAP) && vma_is_fixed_mapping(vma)) return -EINVAL; =20 /* @@ -1827,7 +1826,7 @@ static int check_prep_vma(struct vma_remap_struct *vr= m) if (pgoff + (new_len >> PAGE_SHIFT) < pgoff) return -EINVAL; =20 - if (vma_test_any(vma, VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT)) + if (vma_is_fixed_mapping(vma)) return -EFAULT; =20 if (!mlock_future_ok(mm, vma_test(vma, VMA_LOCKED_BIT), vrm->delta)) --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 A44BE481FD1; Mon, 14 Sep 2026 15:07:45 +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=1789398467; cv=none; b=lQ7aPXIgkYGwp0bJ5DYfPAYHpzmraSU5t9WqlZcM7M0s+7myxwJ7wTPJMg2PPNhrH4R05nsjFDbmH841FSaWqZI3GsNpBV2gLNY1ulCaRIrNmP3yqR0/ZF2Yin/w2oM9Hmo5+m+3XJlWqo9p6+aeGOPTkxDb8RvR6ALeisllqWU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398467; c=relaxed/simple; bh=HTYbod2OP3AjRPEv6Ph886TsUDFUWldGDo6PKBX7Wqs=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=QChbmGaBa9twJuef5c+D9EFiLB4u431luOHhJ/+9qD9e/nDKQSYZAuCNh1zFudaYcOfT/c22rEe7rSHUeKyQ3Hv/U6J43iwRbEXhQh1oLAbMbQdzu7bXOpBLLidz/YwEZF0wyriewGFCkyQd9Ce5Q4lMjh7rEUacbahv981oD6U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HmeQTLrg; 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="HmeQTLrg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 30CD21F000FF; Mon, 14 Sep 2026 15:07:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398465; bh=zqpk9MXgaX25nS5Ys5rO6UCVR/iTsHvR4Kg11ITNpTs=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=HmeQTLrgoimbYzYyF1rT1WkQ6aVpTWU4qFFntK6aiUaKPZLAxsSLWNJ4yY7LD7lbI ZseHju5axoEj1lvyD+W6HgGWBGNzwmVxzDAb9lzGUVPlJbhk1RGmrqj+I5PjXuorcI 5ptV/vMor4Wykd7PBQ+fO5LSx8/pskNH+oZgN53eAveKFqk9QEkbPkWujm1io5dZiv P3TkjeyaWcecyrBNYLy6oibGBT5fPJGeKbWVBD7HKivHa+6othTPwyXbYJZB958Ief skQOSisyvVnwpjZKFfWee1UUWLZmK1jFOBTNh2iKT/aO1o84xoyMFpf9/i5/OkOe34 sEilfyVorcz+g== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:38 +0100 Subject: [PATCH v2 18/40] scsi: sg: convert mmap hook to mmap_prepare and rework Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-18-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=5937; i=ljs@kernel.org; h=from:subject:message-id; bh=HTYbod2OP3AjRPEv6Ph886TsUDFUWldGDo6PKBX7Wqs=; b=kA0DAAoWz53NioHifxQByyZiAGqoC7CifAo2LYHs93Csrg+FAX/PITR+MsmaU7ihJZemgKNxJ Ih1BAAWCgAdFiEE5/QXv1IUVp6J0E9Gz53NioHifxQFAmqoC7AACgkQz53NioHifxSgXQD/YHmd +7NVyi7o2SOOfYbqXyUEIdYXlh9OoJdt4BbzpFkA/05DF7kkq2mIvCKe8SkscJWlGPSdAqoROH6 pVT6HQ3MO X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Move from the deprecated mmap hook to the new mmap_prepare hook. We are mapping kernel pages here, so use the discontiguous kernel mapping mmap action to do so. Unwind the rather confusing loop and instead map as many pages as we can at one time. Note that we do not need to pay attention to rsv_schp->k_use_sg here, as the pages are populated for the length of the buffer at rsv_schp->page_order granularity as compound pages. The discontiguous kernel page mapping logic handles the compound pages for us. sfp->mmap_called keeps the buffer stable for us. As before it is never cleared, so a failed mmap also leaves it set. We also remove some useless vma, vma->vm_file NULL checks - these will always be non-NULL if you reached the mmap hook logic. We retain log output for consistency, but change what's output on page mapping to indicate that sg_discontig_get() does the work now. Note that we drop the VMA_IO_BIT flag for the VMA here. It was never necessary as we invoke alloc_pages() which gives us refcounted folios that are fine for GUP to access (VMA_IO_BIT would prevent that). Signed-off-by: Lorenzo Stoakes (ARM) --- drivers/scsi/sg.c | 115 ++++++++++++++++++++++++--------------------------= ---- 1 file changed, 51 insertions(+), 64 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 5408f002e6c0..3f9e08725602 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1212,85 +1212,72 @@ sg_fasync(int fd, struct file *filp, int mode) return fasync_helper(fd, filp, mode, &sfp->async_qp); } =20 -static vm_fault_t -sg_vma_fault(struct vm_fault *vmf) +static int sg_discontig_init(void *vm_private_data, void **private) { - struct vm_area_struct *vma =3D vmf->vma; - Sg_fd *sfp; - unsigned long offset, len, sa; - Sg_scatter_hold *rsv_schp; - int k, length; - - if ((NULL =3D=3D vma) || (!(sfp =3D (Sg_fd *) vma->vm_private_data))) - return VM_FAULT_SIGBUS; - rsv_schp =3D &sfp->reserve; - offset =3D vmf->pgoff << PAGE_SHIFT; - if (offset >=3D rsv_schp->bufflen) - return VM_FAULT_SIGBUS; - SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp, - "sg_vma_fault: offset=3D%lu, scatg=3D%d\n", - offset, rsv_schp->k_use_sg)); - sa =3D vma->vm_start; - length =3D 1 << (PAGE_SHIFT + rsv_schp->page_order); - for (k =3D 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) { - len =3D vma->vm_end - sa; - len =3D (len < length) ? len : length; - if (offset < len) { - struct page *page =3D rsv_schp->pages[k] + (offset >> PAGE_SHIFT); - get_page(page); /* increment page count */ - vmf->page =3D page; - return 0; /* success */ - } - sa +=3D len; - offset -=3D len; + const unsigned long req_sz =3D (unsigned long)*private; + Sg_fd *sfp =3D vm_private_data; + Sg_scatter_hold *rsv_schp =3D &sfp->reserve; + int err =3D 0; + + mutex_lock(&sfp->f_mutex); + if (req_sz > rsv_schp->bufflen) { + err =3D -ENOMEM; /* cannot map more than reserved buffer */ + goto out; + } + sfp->mmap_called =3D 1; /* Prevents changes to buffer size. */ +out: + mutex_unlock(&sfp->f_mutex); + return err; +} + +static int +sg_discontig_get(struct discontig_kernel_page_state *state) +{ + Sg_fd *sfp =3D state->vm_private_data; + Sg_scatter_hold *rsv_schp =3D &sfp->reserve; + const unsigned int order =3D rsv_schp->page_order; + const pgoff_t nr_pages =3D state->nr_pages_mapped; + + if (nr_pages >=3D (rsv_schp->bufflen >> PAGE_SHIFT)) { + discontig_kernel_map_abort(state); + return 0; } =20 - return VM_FAULT_SIGBUS; + SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp, + "%s: offset=3D%lu, scatg=3D%d\n", __func__, + nr_pages << PAGE_SHIFT, rsv_schp->k_use_sg)); + + discontig_kernel_map_page(state, rsv_schp->pages[nr_pages >> order]); + return 0; } =20 -static const struct vm_operations_struct sg_mmap_vm_ops =3D { - .fault =3D sg_vma_fault, +static const struct discontig_kernel_page_ops sg_discontig_ops =3D { + .init =3D sg_discontig_init, + .get =3D sg_discontig_get, }; =20 static int -sg_mmap(struct file *filp, struct vm_area_struct *vma) +sg_mmap_prepare(struct vm_area_desc *desc) { - Sg_fd *sfp; - unsigned long req_sz, len, sa; - Sg_scatter_hold *rsv_schp; - int k, length; - int ret =3D 0; + Sg_fd *sfp =3D desc->file->private_data; + const unsigned long req_sz =3D vma_desc_size(desc); =20 - if ((!filp) || (!vma) || (!(sfp =3D (Sg_fd *) filp->private_data))) + if (!sfp) return -ENXIO; - req_sz =3D vma->vm_end - vma->vm_start; + SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp, "sg_mmap starting, vm_start=3D%p, len=3D%d\n", - (void *) vma->vm_start, (int) req_sz)); - if (vma->vm_pgoff) + (void *) desc->start, (int) req_sz)); + + if (desc->pgoff) return -EINVAL; /* want no offset */ - rsv_schp =3D &sfp->reserve; - mutex_lock(&sfp->f_mutex); - if (req_sz > rsv_schp->bufflen) { - ret =3D -ENOMEM; /* cannot map more than reserved buffer */ - goto out; - } =20 - sa =3D vma->vm_start; - length =3D 1 << (PAGE_SHIFT + rsv_schp->page_order); - for (k =3D 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) { - len =3D vma->vm_end - sa; - len =3D (len < length) ? len : length; - sa +=3D len; - } + vma_desc_set_flags(desc, VMA_DONTEXPAND_BIT, VMA_DONTDUMP_BIT); + desc->private_data =3D sfp; =20 - sfp->mmap_called =3D 1; - vm_flags_set(vma, VM_IO | VM_DONTEXPAND | VM_DONTDUMP); - vma->vm_private_data =3D sfp; - vma->vm_ops =3D &sg_mmap_vm_ops; -out: - mutex_unlock(&sfp->f_mutex); - return ret; + mmap_action_map_discontig_kernel_pages(desc, (void *)req_sz, + &sg_discontig_ops); + return 0; } =20 static void @@ -1415,7 +1402,7 @@ static const struct file_operations sg_fops =3D { .unlocked_ioctl =3D sg_ioctl, .compat_ioctl =3D compat_ptr_ioctl, .open =3D sg_open, - .mmap =3D sg_mmap, + .mmap_prepare =3D sg_mmap_prepare, .release =3D sg_release, .fasync =3D sg_fasync, }; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 2A98E314D18; Mon, 14 Sep 2026 15:08:12 +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=1789398494; cv=none; b=AALHi5iWssD6Gkl3Sjl1K62A4rszA7dxjnHBhd29iSfmtQmzmR0KVJtty92JxqBAjlLNimJvGn+OcOozhTWLBFMqU3/lTAJ1RthLFOYWrEi3qNPX4m6R+XZJC600Hj/ZxRnlhSO0MSUs5uuNmvd9UdOMft//QG4VcGHyP1EoU/I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398494; c=relaxed/simple; bh=In9WHX8b1sLbbe6jUcP+2i7LCzJ4p//dj4w0OtHuz9I=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=uIJNSl0spioGj0rjbGgtsMuAT68de1uBVD6bOitZ+LfAu7mIMyISFMliqSG+777qDt5uBO0CKuUKrisUsZ3iASkZ4DiAoqakmjM5NYOOvyvo2j6LcFd7fiC3vkx17OEfzi5fTT6ammtzsWb0nrQUMjmNXHqoa3koAamaCvgKgRU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D3SID+QT; 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="D3SID+QT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAD821F00898; Mon, 14 Sep 2026 15:07:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398492; bh=R1TTFxJqK2JOmLB4wxg0hlSgvzQnwmSO7NGWVXFT9S4=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=D3SID+QTMVIxAwuC7b4lzRGl//RePyvZ5Z0Rt9/ReqA80gAvfgu18KAR33H/vFkd1 mjxGVZ/vQPjudqzTTrxeNOlOY1QHYbIUaBqTlc4gzJE3VJOpLm4XmsSxCCVRTE1Glb I3TJHXz6oKhlHqNFPgUp0l1qm/B1Bdi0QqVGl2voszPJbbKmst1KoMaR2I0+CWcg20 isVInCLJyvSnbZVLP2gLNZowX6+eDdmaGbjObtinB4B5s1NkCHLOBIamdYQq5DpkKG kaPq5qVO3GsOIWnlQkv+fwdh86NoMmI+DeZ06iECEVTOEMw6tcxhPY10Et8D/bBCOy wo0WN06hrd6iQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:39 +0100 Subject: [PATCH v2 19/40] fbdev: defio: assert FBINFO_VIRTFB, drop VM_IO, add VM_MIXEDMAP Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-19-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2362; i=ljs@kernel.org; h=from:subject:message-id; bh=In9WHX8b1sLbbe6jUcP+2i7LCzJ4p//dj4w0OtHuz9I=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG9Y8Vrll203D8+/BF/9P/8mz3GwefDPftETA7mq8 tclH2V/d5SyMIhxMciKKbI8/yK+P0gkbF7nBX83mDmsTCBDGLg4BWAiJ1cwMrTttmnq3PxEKefq nbnZqRm/RGfM3XgqSla1PIGxja9mtzvD/9S4pbrnRGSf/XWIYdk8aZeZV9bcL6tuJbxRYl+vrtC TyA8A X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Currently all drivers which use defio allocate system memory. All of them also set FBINFO_VIRTFB, other than ssd1307fb, however this driver allocates system RAM, so simply failed to set this flag when it ought to. This patch sets FBINFO_VIRTFB on ssd1307fb probe, then drops setting VM_IO in fb_deferred_io_mmap() and instead requires FBINFO_VIRTFB to be set, erroring out with a kernel warning if not. The logic requires a page from the driver and since commit 1ecbc7dd2902 ("fbdev/deferred-io: Always call get_page() for framebuffer pages") has always required it to be refcounted, so this was implicitly already the case. Finally this patch sets VM_MIXEDMAP, as the logic is mapping kernel-allocated memory so this is appropriate. Reviewed-by: Thomas Zimmermann Signed-off-by: Lorenzo Stoakes (ARM) --- drivers/video/fbdev/core/fb_defio.c | 6 +++--- drivers/video/fbdev/ssd1307fb.c | 2 ++ 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core= /fb_defio.c index fd00b86e1ae6..fb359ecc3966 100644 --- a/drivers/video/fbdev/core/fb_defio.c +++ b/drivers/video/fbdev/core/fb_defio.c @@ -366,13 +366,13 @@ int fb_deferred_io_mmap(struct fb_info *info, struct = vm_area_struct *vma) { vma->vm_page_prot =3D pgprot_decrypted(vma->vm_page_prot); =20 + if (WARN_ON_ONCE(!(info->flags & FBINFO_VIRTFB))) + return -EINVAL; if (!try_module_get(THIS_MODULE)) return -EINVAL; =20 vma->vm_ops =3D &fb_deferred_io_vm_ops; - vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP); - if (!(info->flags & FBINFO_VIRTFB)) - vm_flags_set(vma, VM_IO); + vm_flags_set(vma, VM_MIXEDMAP | VM_DONTEXPAND | VM_DONTDUMP); vma->vm_private_data =3D info->fbdefio_state; =20 fb_deferred_io_state_get(info->fbdefio_state); /* released in vma->vm_ops= ->close() */ diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307f= b.c index c4fdecafd856..958514a35433 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -763,6 +763,8 @@ static int ssd1307fb_probe(struct i2c_client *client) info->fix.smem_start =3D __pa(vmem); info->fix.smem_len =3D vmem_size; =20 + info->flags =3D FBINFO_VIRTFB; + fb_deferred_io_init(info); =20 i2c_set_clientdata(client, info); --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 EFE6844063D; Mon, 14 Sep 2026 15:08:40 +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=1789398522; cv=none; b=iBY/7+KMDSkug76SPEX2Xl0hGQDUuWaHORwzlamAQ2w63AjrehTowx3Lbp7NO3rFU6Y11Du1C3ELoioR3JE5wZi88AeAZmeLAArXeiOafO9ld4amMkXZZghbfXSRpSnBy3xNhiRo+l/79D4fFpfY+two9bsvGbVhzQ1XYNppjQU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398522; c=relaxed/simple; bh=GNn4/WHo/gNb5sHnp4BEq122HpiBRxK72Bb5u1n+58g=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=FnD4TWdxXiLdE1kShdq1jGCBdHdPZOZllj5rxBfvwwb634lBsp4Jqco4QYXetYNQPji47hqXMuRENyeLuPHLmksMCyV1CAeUOLz0upu574MBkCiBc2Jd8UtTgFl6u/m/dV/3gAyqfL0YwQ7p3OrQQqDtiroG7/LQXp1779PsIr4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UziRXkB8; 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="UziRXkB8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E7DC1F000FF; Mon, 14 Sep 2026 15:08:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398520; bh=FhSwIhda5SwYvYTkOqlzzzYcm2yovY5S5sJ87DUE+qE=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=UziRXkB8qeSmqlpvH0/NIIVjVlvQFMtZLRcgdF/oXLW1jALG9rz68famtPGxfLLRs ji+y6RHPJeqximzqtvzaSgpAc4uXtBs/AMiDNlmrLZ47tNoBw3/ehPBq1GU+cLbJs4 PtV0usZP8WfROMhRCoKLEls1iPIULSzemQVda7uTFDM5Zth9eIIe+IOt5/gcqWaics +A/fYodcbCpRBT8PQwbnjmpnErJp/wDNYP0A5jHhXz0HpAeGt1EUKsfw2qVCWjvnMu tvLS7QNxc97ZPr5o+qhHhw0Avm/Rxv7LXwKdr3G/PyVf9ypPArUlzvdv7RdyeZfcoP 7xyKOl+2eOqxQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:40 +0100 Subject: [PATCH v2 20/40] HSI: cmt_speech: convert mmap hook to mmap_prepare, refactor Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-20-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2632; i=ljs@kernel.org; h=from:subject:message-id; bh=GNn4/WHo/gNb5sHnp4BEq122HpiBRxK72Bb5u1n+58g=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG8s77svu6u5dsuErBTja8a37zyVSJt9796Z3YtK6 7f33TQM6ShlYRDjYpAVU2R5/kV8f5BI2LzOC/5uMHNYmUCGMHBxCsBE3LIZGU5fWS/bJcm2O/Xy 19eHU4M1av5JSFhFFIbqtl6SL6jXfcnwP/iD4rvg+8YGP2rkw57pN8j0rTiv4WXNP6/xgxPXg6j PrAA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Use the mmap_prepare in favour of the deprecated mmap hook as part of the work to convert one to another. Since this is simply a refcounted kernel page that has been allocated, it should not be marked VM_IO and should be inserted using the kernel page insertion mechanism, so convert it to do this instead. Use the VMA descriptor's private data field as a scratch buffer to store the page in - this stays valid throughout the kernel page mapping operation. Signed-off-by: Lorenzo Stoakes (ARM) --- drivers/hsi/clients/cmt_speech.c | 33 +++++++++------------------------ 1 file changed, 9 insertions(+), 24 deletions(-) diff --git a/drivers/hsi/clients/cmt_speech.c b/drivers/hsi/clients/cmt_spe= ech.c index 7226677ebde7..801697b74d4f 100644 --- a/drivers/hsi/clients/cmt_speech.c +++ b/drivers/hsi/clients/cmt_speech.c @@ -1084,22 +1084,6 @@ static void cs_hsi_stop(struct cs_hsi_iface *hi) kfree(hi); } =20 -static vm_fault_t cs_char_vma_fault(struct vm_fault *vmf) -{ - struct cs_char *csdata =3D vmf->vma->vm_private_data; - struct page *page; - - page =3D virt_to_page((void *)csdata->mmap_base); - get_page(page); - vmf->page =3D page; - - return 0; -} - -static const struct vm_operations_struct cs_char_vm_ops =3D { - .fault =3D cs_char_vma_fault, -}; - static int cs_char_fasync(int fd, struct file *file, int on) { struct cs_char *csdata =3D file->private_data; @@ -1256,18 +1240,19 @@ static long cs_char_ioctl(struct file *file, unsign= ed int cmd, return r; } =20 -static int cs_char_mmap(struct file *file, struct vm_area_struct *vma) +static int cs_char_mmap_prepare(struct vm_area_desc *desc) { - if (vma->vm_end < vma->vm_start) - return -EINVAL; + struct file *file =3D desc->file; + struct cs_char *csdata =3D file->private_data; + struct page **pages =3D (struct page **)&desc->private_data; =20 - if (vma_pages(vma) !=3D 1) + if (vma_desc_pages(desc) !=3D 1) return -EINVAL; =20 - vm_flags_set(vma, VM_IO | VM_DONTDUMP | VM_DONTEXPAND); - vma->vm_ops =3D &cs_char_vm_ops; - vma->vm_private_data =3D file->private_data; + vma_desc_set_flags(desc, VMA_DONTDUMP_BIT, VMA_DONTEXPAND_BIT); =20 + *pages =3D virt_to_page((void *)csdata->mmap_base); + mmap_action_map_kernel_pages_full(desc, pages); return 0; } =20 @@ -1353,7 +1338,7 @@ static const struct file_operations cs_char_fops =3D { .write =3D cs_char_write, .poll =3D cs_char_poll, .unlocked_ioctl =3D cs_char_ioctl, - .mmap =3D cs_char_mmap, + .mmap_prepare =3D cs_char_mmap_prepare, .open =3D cs_char_open, .release =3D cs_char_release, .fasync =3D cs_char_fasync, --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 46B7149B5DC; Mon, 14 Sep 2026 15:09:08 +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=1789398549; cv=none; b=H5B022N1/jliY/nnMHd/mBhFSd9KSl9pAzFm69hkN3z71PX0cOoQYoB78bhlPfH4LbOB2t7iDlyBlBliL8S/7PXvP1cFHW9o6qrv3NIMpy1svIvifjRl5b+ud3BB83Rw//AXrD/EVraleiW+sBIth0sVQS+SQWHtFudSXhUX41U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398549; c=relaxed/simple; bh=NwkWQQ7fmwzL5QGJDJ/xCgQWUhs8DQGRd4wM7Vj8ofA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=knY9LLtmS6TaHHzwTrwSsHILBfsGD96vngDiYlIBWdPjuVfhjhghaNL0TmMttNe6AIInqYAkdX8QxoCqQQsAC4cQQmfryTLCxTQ9DYpNgG9F2GPXqwFglIEVIOabqdSdc6E4ydn7BmI7YSoImCjTIVkcmPiUrxARIZffv5exEPY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L7mvUocc; 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="L7mvUocc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5A3C1F00893; Mon, 14 Sep 2026 15:08:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398547; bh=rtYEyCC7VKqkqWelOuwt2okny02CJhbQpnc+ekNFEso=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=L7mvUocc07dvv4gNRBD8FIWMRw7VSN7mZvf6vuvnYrejYxLoZ3JQAGznHWhHn3hPA 2PiUTFskJ2XtBWABty1VWW1V7Pb/ZwQ3hwijjQiJTWJxu3PbQMoWTLTHJG3w3UxY2t q4tvQVRUmvdYzcG7cEjBUqL/GgjULYotnn0bklOa8SqIVfHw/4Oe7cGpeqcOk/f56H kZnbdU2P3VZTSfuidrq48vWeO3Vqfjywr3cgsJsfQNdp6Kmq8KDDFsgJTxKTYrCSsx KY/d5zQgTuZMRlHJAEFa2kS77Esqf2EVcl4XRAYg+l/+glQcIQjHPAWR0icTcJgUE+ RI/ZcB7u1K4ag== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:41 +0100 Subject: [PATCH v2 21/40] mm/gup: error out early on !VMA_MAYREAD_BIT VMAs Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-21-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=1289; i=ljs@kernel.org; h=from:subject:message-id; bh=NwkWQQ7fmwzL5QGJDJ/xCgQWUhs8DQGRd4wM7Vj8ofA=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG/k+RBscrhhwTaTCRnnfC5YPbGVstvt9UpAnv1zz /41fH6zO0pZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjARRT1Ghjv+HGs7lZ2Cn/31 1J75MPmTf3vV879Pb9ybfkn6N2PP3csM/10eP7h+eX/5fBV+hikawu4sc27YW+zalf3t6WHvwqN x7zkB X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 When populating a VMA range via the aptly named populate_vma_page_range() an unreadable VMA will always eventually fail with -EFAULT. That a VMA is accessible is always checked, however VMA_MAYREAD_BIT is not. All user mappings always have VMA_MAYREAD_BIT set, so this check only impacts kernel mappings. It is implemented specifically to disallow population of uprobes XOL mappings which are exec-only. A nasty interaction with these mappings may occur if they are mlocked, so actively disallow this early. This allows a subsequent commit to remove the VM_IO check in __mm_populate() which otherwise requires non-MMIO mappings to be wrongly flagged simply as a workaround. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/gup.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index c2dfcb4744bc..e6310a7cc05b 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1836,6 +1836,10 @@ long populate_vma_page_range(struct vm_area_struct *= vma, if (!vma_is_accessible(vma)) return -EFAULT; =20 + /* Unreadable VMAs also cannot be faulted in. */ + if (!vma_test(vma, VMA_MAYREAD_BIT)) + return -EFAULT; + gup_flags =3D FOLL_TOUCH; /* * We want to touch writable mappings with a write fault in order --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 BABF3481255; Mon, 14 Sep 2026 15:09:35 +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=1789398580; cv=none; b=FOcVB7aMWzmYiPeaY7T6sp9jYu9N5jTv1JesJ1dDD7VTA0Xqq8maz358y6QxLAUQq6NIqWNR6UF0YwwZnVGHmQNv+HSCZutS1mrOIzbPBNikbHhYAtTzhnNFZCDv2iSPyqdFVH0ceeHeJRGIkk09YHSrekM7bthg/QFumGpsacs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398580; c=relaxed/simple; bh=joQXUjvjM3OjL+Ta6QEJ1w5g7Vsv4M79ot1AULAZKpk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=kBgfgtsrvXt81W1ygWvjG7qv7gEZe97pfarHjN7udGK8vObqymgSPtP1CK042kHWS5iamjxhwGnth4b0sij2B8PWLu36zCGOdeyDzcTYLM+Jc7ADhPbCb6V4LtxxWp39wqmM1+1ZvoTCKHn20djjrJyl4CDCYmFexUeKQjFUKdg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hrvl0D0j; 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="hrvl0D0j" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A7561F000FF; Mon, 14 Sep 2026 15:09:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398575; bh=GfRJzELhUA3zmjv637fDp+tblD+oWrGBxslIXX4F7cw=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=hrvl0D0jcUyh6uvN3XebCBKsuFl+Mh+LBuw54wmgiYZ5pJic6J+FDi7a7/oYIZbrN WQowmRaCgo8p7AykmaIoxZo/pJ2dHmUB9gbcFhmWl45G2Mhh4yFuopGrBcctiaM3El 68DDeLDxRrJU/lwaOEljlbe9r0ocz39Hh4x2JFFkZNeVrvdYx+9pruOj7yeOkUdJdz 9ayyQuXCEa9/XjgJ7X8EW3xxS5gu5Ksv+bqTx+v392geCiZRa/zUWP9Lprrt22EWHe i8V2yIXKCyWHgu7EKnmmt0Nm7KISk8cPtnmCihwyqZVRlPc2i1GMkwKxnVo8S8rDqM XfgZBeADzZr8g== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:42 +0100 Subject: [PATCH v2 22/40] uprobes: remove VM_IO, set VM_MIXEDMAP for mapped kernel pages Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-22-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2070; i=ljs@kernel.org; h=from:subject:message-id; bh=joQXUjvjM3OjL+Ta6QEJ1w5g7Vsv4M79ot1AULAZKpk=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG+UmWFxrd5rX01VbImjwcymWUd7HFT3MX92PMF2e /PkB5K3OkpZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjCRu38Z/pcr1KWXq5Uo9Rn8 OHKxm9XRopRX32vrvYe8rb0uOxv4+Rn+l6+M/c59213zYUxKnlCarmzPTE253GMTvmzNPZN/b94 bJgA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 These are not MMIO pages so VMA_IO_BIT is an inappropriate flag to set. Instead, set them VMA_MIXEDMAP_BIT as they are kernel mappings and this is the appropriate flag to set for those. This provides the semantics required - no VMA merging is permitted, but does not prevent GUP. However this has no meaningful impact as these are refcounted and thus can be GUPed. A previous commit already prevented __mm_populate() from being invoked on XOL areas, which VMA_IO_BIT was previously relied upon to do, so that is no longer required. Both VMAs set a VMA name, so always_dump_vma() returns true before vma_dump_size() reaches its VMA_IO_BIT check, and thus there is no change in core dump behaviour. Change this for both the core xol_add_vma() function and the x86-specific get_uprobe_trampoline() function. Signed-off-by: Lorenzo Stoakes (ARM) --- arch/x86/kernel/uprobes.c | 2 +- kernel/events/uprobes.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 65a2de82ecd2..0f60c0d076b6 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -715,7 +715,7 @@ static struct vm_area_struct *get_uprobe_trampoline(str= uct mm_struct *mm, unsign =20 *new_mapping =3D true; return _install_special_mapping(mm, vaddr, PAGE_SIZE, - VM_READ|VM_EXEC|VM_MAYEXEC|VM_MAYREAD|VM_IO, + VM_READ|VM_EXEC|VM_MAYEXEC|VM_MAYREAD|VM_MIXEDMAP, &tramp_mapping); } =20 diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 7709ea882477..b89cc5cee002 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1726,8 +1726,8 @@ static int xol_add_vma(struct mm_struct *mm, struct x= ol_area *area) } =20 vma =3D _install_special_mapping(mm, area->vaddr, PAGE_SIZE, - VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO| - VM_SEALED_SYSMAP, + VM_EXEC|VM_MAYEXEC|VM_DONTCOPY| + VM_MIXEDMAP|VM_SEALED_SYSMAP, &xol_mapping); if (IS_ERR(vma)) { ret =3D PTR_ERR(vma); --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 10C4146F4B3; Mon, 14 Sep 2026 15:10:03 +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=1789398606; cv=none; b=J4XGRfqtu6JUjm+l+BnNa3Rkd9LKy6efbjQb19Tt7dWeTMMsCCntN70hYDsw9nTVb6MnroN8QUyNC1f/0DvoZRiajDwmuWLcS8t+NvD0R+q+01SlGhpQHa3k4yMMumt8st7oZ2Nc8rcmoooE7miRrLr07BXZpEfQ4nYX8mQfUUQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398606; c=relaxed/simple; bh=BsZqCDBeNZFMnLDuCh83Km3v/CdnahcHMG4JtnCdsfU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=agNRSUT/yKwCVRahDwPOHy3BwsGyT4lTigBz9Dg6zQpYfs9hHqmjMOP+e2xHryU8KLhvc2ouCKvVrYFpEBySyTCXTBkW+/MgN2Phou2TvFIEYcxR86/3m8h4/wSZ5fmLP9QJUafujBBioDXScAhK+nmsmyz2T/xFBEHFz3iht0k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bwmD/Jom; 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="bwmD/Jom" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E29411F00899; Mon, 14 Sep 2026 15:09:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398603; bh=uq2xWQ1p6mPiNzp++s6Aro3m2E6wKT5sSjQYvI7TYg4=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=bwmD/JombA0FO9sHhGiNJeS+ZvfheSA2psdLNu15mTk14rHrqYQ/IPA/3U9osrT+E xe39lsxBQOZZqjwvEM+rcTzfDj1ai5jy7AY57BD5ejit2mVRCobgEvn/nFrGpVDf7m f25BnyZENCEruuQWi5TZK3sg0ODagQlo3M5aesNNtGvWo+Ztie81hj9SDBnfrCIwMV EEX5U6G0fLVmKsHUFtz0/YenMyf5kLX/LNx9mXftV1CQ0Ths8Z4US4czSQIb09tO4F ENszegDt2bEYLVaYQ6UCvJtW+bGYP4XAoE9BZaiCaSrIBY+HcYyoIIIFJaFKtJQnnb kIUwHj7LB/SNQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:43 +0100 Subject: [PATCH v2 23/40] mm/mlock: clear VMA_LOCKED_MASK over mmap callback Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-23-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2686; i=ljs@kernel.org; h=from:subject:message-id; bh=BsZqCDBeNZFMnLDuCh83Km3v/CdnahcHMG4JtnCdsfU=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG90KEmdmv3sU+TkKlvftOYi640HdivPDj6SPf/Fm ZOLrprv6ihlYRDjYpAVU2R5/kV8f5BI2LzOC/5uMHNYmUCGMHBxCsBEgvQY/ucXzf+Qv212a3LE dr/5c/q9Xj86bZW+8d7W2Ehl6QCPXV8Z/go0LK9fn1Z0oJd/34KkKzan/O9d2nrvxZ0XgROrvp7 5Y8AFAA== X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Currently there's a confusing mess around VMA_LOCKED_BIT and VMA_LOCKONFAULT_BIT. It is permitted for drivers to set any flags they like, with the VMA already possessing lock flags. This results in the absurd situation of a VMA possessing both VMA_SPECIAL_FLAGS and VMA_LOCKED_MASK flags, which is not permitted. This has resulted in mlock_vma_folio() having a very silly check for this scenario to work around it. There is no need for this - just clear the flags before invoking the hook and reinstate them afterwards if they are required. Nothing relies upon this being set during the mmap operation. mmap_prepare is unaffected by this so requires no fix. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/internal.h | 9 +-------- mm/vma.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 8 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index 3a395e8c224c..9108b2b2cd03 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -969,14 +969,7 @@ void mlock_folio(struct folio *folio); static inline void mlock_vma_folio(struct folio *folio, struct vm_area_struct *vma) { - /* - * The VM_SPECIAL check here serves two purposes. - * 1) VM_IO check prevents migration from double-counting during mlock. - * 2) Although mmap_region() and mlock_fixup() take care that VM_LOCKED - * is never left set on a VM_SPECIAL vma, there is an interval while - * file->f_op->mmap() is using vm_insert_page(s), when VM_LOCKED may - * still be set while VM_SPECIAL bits are added: so ignore it then. - */ + /* The VM_IO check prevents migration from double-counting during mlock. = */ if (unlikely((vma->vm_flags & (VM_LOCKED|VM_SPECIAL)) =3D=3D VM_LOCKED)) mlock_folio(folio); } diff --git a/mm/vma.c b/mm/vma.c index d71ec51255b1..c6ed04d27351 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2607,6 +2607,11 @@ static int __mmap_new_file_vma(struct mmap_state *ma= p, if (!map->vm_file->f_op->mmap) return 0; =20 + /* + * Driver-specified flags may make the lock flags invalid, so clear + * VMA_LOCKED_MASK and reinstate it afterwards if appropriate. + */ + vma_clear_flags_mask(vma, VMA_LOCKED_MASK); error =3D mmap_file(vma->vm_file, vma); map->vm_file =3D vma->vm_file; =20 @@ -2623,6 +2628,15 @@ static int __mmap_new_file_vma(struct mmap_state *ma= p, return error; } =20 + /* If VMA flags still valid for locked mask, reinstate. */ + if (vma_supports_mlock(vma)) { + const vma_flags_t mask =3D + vma_flags_and_mask(&map->vma_flags, + VMA_LOCKED_MASK); + + vma_set_flags_mask(vma, mask); + } + map->vma_flags =3D vma->flags; =20 return 0; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 00B0E47D934; Mon, 14 Sep 2026 15:10:31 +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=1789398632; cv=none; b=mAEBsqmwBF6s67ZY+l1cUWpALb1kP3g7QuYhp8rUixsIh+p67wzvLplOfV60Ya0jqHf0xCppBNEzUgpUvJfveqefxDQUforhY5aysOqbK4TFdfHHLYevETLzmO1Nf1+w14rogUoQP31+ijyeIUXUhxytWD8gqbuxdx1bNDLzbsA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398632; c=relaxed/simple; bh=LWjLvXpzP5ioA18RZMNyCTmiGfPWwU026RHbvaGfA8Y=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=vGBREdl2nAdiEbFWDi6X19azeBz+y2lTE79/LD6Wp1P7gMai38cC4HSGZvhRrAqNehy/Szdyoa0JMyUGVvIvqV+4EnIkZ0um9kcTp7dc5MTrxzkGgTvhPRe2F8kRBFIHNZHcAh0c0L9bLvhR6K9ghAtBGXTeSIoczu1tb+tSHMM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EC3hWABU; 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="EC3hWABU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CEE2A1F000FF; Mon, 14 Sep 2026 15:10:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398630; bh=ysDxNe9p0/WTN7xWlWhpkS5/GM4BhQBCxlnaA2mG7QA=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=EC3hWABUfzlAOdNPy8LeNqD4nWhs3ijaF/mRxRs2ZDJT63mExVN9JZVr/EbHw+vyB ZpAzd6VT3VoOw5xvJInfqk71FOF97WLP3d950mZtPjuoV07CpesE0g6rRYqjYNppa/ WSYalyz7QeBc+sdcCRgQdPgin1H7vBrAO86B3RYdFvtEMIALKxxTWzFinotrsI7WWZ BfvdZDS4JqWZKrMElvDsjboqQNLlrerceLrkeqpYav9+swU4Ktfoo8EhroY1quIOO8 lXa+OSPTY7BtrqNnOGVgvXUlx2HrBu9Mgi4PvEtj16OaihwnyWnnCU2PDrMCVqvaVl NscfwukEXyeHQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:44 +0100 Subject: [PATCH v2 24/40] mm/mlock: eliminate weird VMA_IO_BIT abuse and simplify Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-24-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=7394; i=ljs@kernel.org; h=from:subject:message-id; bh=LWjLvXpzP5ioA18RZMNyCTmiGfPWwU026RHbvaGfA8Y=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG8Mnrrm+Jy+T2u39jfx9LFnFRp3c5i9Yr0/x61Bl L3t2cvXHaUsDGJcDLJiiizPv4jvDxIJm9d5wd8NZg4rE8gQBi5OAZiI0wlGhhu8Sh8vO6Sc/cye bBozJ3SV7bSHn0xXmT9/uv3mVf6j9VmMDBf96i3mckoYn3hx3qJIeyfPdbYjhaqrpYWyzWceTnA LYAIA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 When performing mlock() or munlock() otherwise normal VMAs have VMA_IO_BIT solely to fix a race with migration which might otherwise double-count mlock VMAs. This is unnecessary - at the point of applying folio mlock state, whether setting or clearing PG_mlocked, we know whether or not we are locking. Solve this in two ways - thread a boolean through the page table walk indicating whether a lock or unlock is being performed, and run a locking walk with VMA_LOCKONFAULT_BIT set and VMA_LOCKED_BIT cleared. This state never occurs otherwise, as VMA_LOCKONFAULT_BIT always implies VMA_LOCKED_BIT. These are also always cleared together. Then, update folio_add_lru_vma() and mlock_folio() to check only for VMA_LOCKED_BIT, and update try_to_unmap_one() to check for VMA_LOCKED_MASK instead. Also remove the useless invocation of allow_mlock_munlock() which simply returns true if unlocking and instead rename it to allow_mlock() and only call it when locking. Finally, with the other mlock abuse of VMA_IO_BIT addressed, update mlock_vma_folio() and folio_add_lru_vma() to simply test for VMA_LOCKED_BIT. munlock_vma_folio() tests VMA_LOCKED_MASK instead, as an unmap racing with the locking walk must still munlock folios the walk has already counted. While here, also replace some deprecated VMA flag predicates. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/folio.c | 2 +- mm/internal.h | 10 +++++++--- mm/mlock.c | 51 +++++++++++++++++++-------------------------------- mm/rmap.c | 4 +++- 4 files changed, 30 insertions(+), 37 deletions(-) diff --git a/mm/folio.c b/mm/folio.c index 47a437e0f7fd..35e242b48870 100644 --- a/mm/folio.c +++ b/mm/folio.c @@ -505,7 +505,7 @@ void folio_add_lru_vma(struct folio *folio, struct vm_a= rea_struct *vma) { VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); =20 - if (unlikely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) =3D=3D VM_LOCKED)) + if (vma_test(vma, VMA_LOCKED_BIT)) mlock_new_folio(folio); else folio_add_lru(folio); diff --git a/mm/internal.h b/mm/internal.h index 9108b2b2cd03..59cfe336e468 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -969,8 +969,7 @@ void mlock_folio(struct folio *folio); static inline void mlock_vma_folio(struct folio *folio, struct vm_area_struct *vma) { - /* The VM_IO check prevents migration from double-counting during mlock. = */ - if (unlikely((vma->vm_flags & (VM_LOCKED|VM_SPECIAL)) =3D=3D VM_LOCKED)) + if (vma_test(vma, VMA_LOCKED_BIT)) mlock_folio(folio); } =20 @@ -987,7 +986,12 @@ static inline void munlock_vma_folio(struct folio *fol= io, * always munlock the folio and page reclaim will correct it * if it's wrong. */ - if (unlikely(vma->vm_flags & VM_LOCKED)) + /* + * VMA_LOCKONFAULT_BIT alone marks an mlock walk in progress, see + * mlock_vma_pages_range(). An unmap racing with the walk must still + * munlock folios the walk has already counted. + */ + if (unlikely(vma_test_any_mask(vma, VMA_LOCKED_MASK))) munlock_folio(folio); } =20 diff --git a/mm/mlock.c b/mm/mlock.c index 39215a3eab1f..4235a1518fc9 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -316,22 +316,10 @@ static inline unsigned int folio_mlock_step(struct fo= lio *folio, return folio_pte_batch(folio, pte, ptent, count); } =20 -static inline bool allow_mlock_munlock(struct folio *folio, +static inline bool allow_mlock(struct folio *folio, struct vm_area_struct *vma, unsigned long start, unsigned long end, unsigned int step) { - /* - * For unlock, allow munlock large folio which is partially - * mapped to VMA. As it's possible that large folio is - * mlocked and VMA is split later. - * - * During memory pressure, such kind of large folio can - * be split. And the pages are not in VM_LOCKed VMA - * can be reclaimed. - */ - if (!vma_test(vma, VMA_LOCKED_BIT)) - return true; - /* folio_within_range() cannot take KSM, but any small folio is OK */ if (!folio_test_large(folio)) return true; @@ -352,6 +340,7 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long ad= dr, =20 { struct vm_area_struct *vma =3D walk->vma; + const bool lock =3D walk->private; spinlock_t *ptl; pte_t *start_pte, *pte; pte_t ptent; @@ -368,7 +357,7 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long ad= dr, folio =3D pmd_folio(*pmd); if (folio_is_zone_device(folio)) goto out; - if (vma_test(vma, VMA_LOCKED_BIT)) + if (lock) mlock_folio(folio); else munlock_folio(folio); @@ -390,10 +379,10 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long = addr, continue; =20 step =3D folio_mlock_step(folio, pte, addr, end); - if (!allow_mlock_munlock(folio, vma, start, end, step)) + if (lock && !allow_mlock(folio, vma, start, end, step)) goto next_entry; =20 - if (vma_test(vma, VMA_LOCKED_BIT)) + if (lock) mlock_folio(folio); else munlock_folio(folio); @@ -428,31 +417,29 @@ static void mlock_vma_pages_range(struct vm_area_stru= ct *vma, .pmd_entry =3D mlock_pte_range, .walk_lock =3D PGWALK_WRLOCK_VERIFY, }; + const bool lock =3D vma_flags_test(new_vma_flags, VMA_LOCKED_BIT); + vma_flags_t walk_flags =3D *new_vma_flags; =20 /* - * There is a slight chance that concurrent page migration, - * or page reclaim finding a page of this now-VMA_LOCKED_BIT vma, - * will call mlock_vma_folio() and raise page's mlock_count: - * double counting, leaving the page unevictable indefinitely. - * Communicate this danger to mlock_vma_folio() with VMA_IO_BIT, - * which is a VMA_SPECIAL_FLAGS flag not allowed on VMA_LOCKED_BIT vmas. - * mmap_lock is held in write mode here, so this weird - * combination should not be visible to other mmap_lock users; - * but WRITE_ONCE so rmap walkers must see VMA_IO_BIT if VMA_LOCKED_BIT. + * LOCKONFAULT without LOCKED never otherwise occurs: it marks a walk in + * progress so that rmap-side callers, which test VMA_LOCKED_BIT, do not + * count folios, while try_to_unmap_one(), which tests VMA_LOCKED_MASK, + * still refuses to unmap them. */ - if (vma_flags_test(new_vma_flags, VMA_LOCKED_BIT)) - vma_flags_set(new_vma_flags, VMA_IO_BIT); + if (lock) { + vma_flags_clear(&walk_flags, VMA_LOCKED_BIT); + vma_flags_set(&walk_flags, VMA_LOCKONFAULT_BIT); + } + vma_start_write(vma); - vma_flags_reset_once(vma, new_vma_flags); + vma_flags_reset_once(vma, &walk_flags); =20 lru_add_drain(); - walk_page_range_vma(vma, start, end, &mlock_walk_ops, NULL); + walk_page_range_vma(vma, start, end, &mlock_walk_ops, (void *)lock); lru_add_drain(); =20 - if (vma_flags_test(new_vma_flags, VMA_IO_BIT)) { - vma_flags_clear(new_vma_flags, VMA_IO_BIT); + if (lock) vma_flags_reset_once(vma, new_vma_flags); - } } =20 /* diff --git a/mm/rmap.c b/mm/rmap.c index 5332c52909be..6661bc11ce65 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2239,9 +2239,11 @@ static bool try_to_unmap_one(struct folio *folio, st= ruct vm_area_struct *vma, =20 /* * If the folio is in an mlock()d vma, we must not swap it out. + * VMA_LOCKONFAULT_BIT alone marks an mlock walk in progress, see + * mlock_vma_pages_range(). */ if (!(flags & TTU_IGNORE_MLOCK) && - (vma->vm_flags & VM_LOCKED)) { + vma_test_any_mask(vma, VMA_LOCKED_MASK)) { ptes++; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-25-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> To: Andrew Morton , "Liam R. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=988; i=ljs@kernel.org; h=from:subject:message-id; bh=2Jr9TGQDZkUd8fLzavPdA/40vMj/7KYd7/4/rEIq1dg=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG+UVm7geFp/Nd4nyCOl4uJts+L3JptYjA76JEss4 endw/q2o5SFQYyLQVZMkeX5F/H9QSJh8zov+LvBzGFlAhnCwMUpABNpYGf475Q9If+v6fdCTSel /PnVn2ZuTjXccO52NZvg5ofeGZGPmBkZZgu/u8Ji1euQ96dtlu2yY0uvytZrCh/M0yyz2q675ow 9EwA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 It makes no sense for a mapping whose contents the kernel does not own to specify that the range is MMIO. Prior to this patch, all in-tree drivers which did so have been updated such that they are marked as kernel-owned. The check WARNs and fails the mmap for any out-of-tree driver that still sets VMA_IO_BIT without a kernel mapping. No functional change intended for in-tree code. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/vma.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/vma.c b/mm/vma.c index c6ed04d27351..fa429771bea8 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2787,6 +2787,12 @@ static int mmap_validate_vma_flags(const vma_flags_t= *flags) return -EINVAL; #endif =20 + if (!vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT)) { + /* Only kernel-owned mappings may set VMA_IO_BIT. */ + if (WARN_ON_ONCE(vma_flags_test(flags, VMA_IO_BIT))) + return -EINVAL; + } + return 0; } =20 --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 5E9F348C3ED; Mon, 14 Sep 2026 15:11:26 +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=1789398688; cv=none; b=V7Ql+sA9tIYy/v5EBjTMbh93S/y4HtSaeR7Qq0zqv6W3VDRxp615IK8k/Qsq/asXD2NQo8ftk0PnChqtHgF05BxktOhf8AgOJpoHA+cyulVJ0zxs3PTiC14HmAWcKDgJJxAcETzcQOLFD0JAVYfW+d1G0rd9TXbl9MfR3N8zLgE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398688; c=relaxed/simple; bh=uH87TAqeXGzRkFjPPdKsCv8BClVhpn1A0PmRl2JkWNc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=SlN5yigsvS10FmoEAPWtnLGEnkv3ogm7CQjHUrASTCoLo2uYnhDodVUZqoi2f1iOY+ktoRWCFGFuGzO7s/Jfo0t4WxPBYwgUW2WssSmvqknrYpW29P3bCU0qQLgpizhMKoQzRQM2en7J6yV6NR8Hz9bPEsT1tBtZ9GScCgMdews= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QVjqSRmu; 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="QVjqSRmu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB9C91F000FF; Mon, 14 Sep 2026 15:10:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398686; bh=IY1hkyQnxRgKar673Yy42geoBDUpVDyAEE35Bg2bTi4=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=QVjqSRmuwHcku5tS2EBp+UM1l6k3TuMyDGxNdv7tBUq1ayVqyJBEPcMGonBWH2mbt CJnpweMQcewTpOK3PuR+WZE3wzW9lnt7wQYxw9ECZwxNcUbNIyhKOxzzYMxAxWI7UF TU6eotkmnW47CVreMrXOa9l+SsVw0Gd93tLpea6D1gCt/QIIA9lgGvjAQk2AukwKki /jgBz8o/xHWz74tspRVZPQHIEB6inXqC0KgEiWAWVOANJupuL+SdC1MP99MlBWIoWd BvGG/iTE6GW25ier5UvU64queTaQhFyZYgU7No2Wl/K5TwbvzajfuOZB4dizpq/z9p r/pZ2Cm72qBgQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:46 +0100 Subject: [PATCH v2 26/40] mm: remove VMA_IO_BIT check in vma[_flags]_is_kernel_owned() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-26-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=uH87TAqeXGzRkFjPPdKsCv8BClVhpn1A0PmRl2JkWNc=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG+yqQ/WP98T8D3z0cT8mN5T3zbfl+DqWf/+9ZvbN e3Sa0Ked5SyMIhxMciKKbI8/yK+P0gkbF7nBX83mDmsTCBDGLg4BWAiPV8ZGV6z70ioaeDuitiw 9rv6q32tc9n7pqVYbE7S2/ta4UHUQT+G/1WpJ8VaD1gFb3nzpHLNvVcP7O+dY2dafXP3toMfr9+ 5+I0ZAA== 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 ca598e5f9715..4b6aa0b47b00 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1630,8 +1630,7 @@ static inline bool vma_is_shared_maywrite(const struc= t 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); } =20 /** 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) =20 for (; vma; vma =3D 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 42f084517247..38fe455dc70c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2343,19 +2343,19 @@ void zap_vma_range(struct vm_area_struct *vma, unsi= gned long address, } =20 /** - * zap_special_vma_range - zap all page table entries in a special vma ran= ge + * 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 addre= ss, unsigned long size) { if (!range_in_vma(vma, address, address + size) || - !(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))) + !vma_is_kernel_owned(vma)) return; =20 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_gat= her *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 =3D vm_get_page_prot(newflags); =20 diff --git a/mm/vma.c b/mm/vma.c index fa429771bea8..54e5f4bbd8af 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2787,7 +2787,7 @@ static int mmap_validate_vma_flags(const vma_flags_t = *flags) return -EINVAL; #endif =20 - 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/du= p.h index 9205ebf31ce7..de429ed4d60c 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -1667,8 +1667,7 @@ static inline bool file_is_dev_zero(const struct file= *file) =20 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); } =20 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/merg= e.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 =3D &mm, .vmi =3D &vmi, }; - vma_flag_t special_flags[] =3D { VMA_IO_BIT, VMA_DONTEXPAND_BIT, + vma_flag_t special_flags[] =3D { VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT }; - vma_flags_t all_special_flags =3D EMPTY_VMA_FLAGS; int i; struct vm_area_struct *vma_left, *vma; =20 - /* Make sure there aren't new VM_SPECIAL flags. */ - for (i =3D 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 =3D 0; i < ARRAY_SIZE(special_flags); i++) { --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 76D2B475355; Mon, 14 Sep 2026 15:11:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=5564; i=ljs@kernel.org; h=from:subject:message-id; bh=7idMlWzMjKkLqO4T4MHFG35a8uf1UQ6cLeMTF/3U+1Q=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG/KWpt0QPvi3IYXLlE37UUfP9AMyGKVD2n686iYa 5P+/a7/HaUsDGJcDLJiiizPv4jvDxIJm9d5wd8NZg4rE8gQBi5OAZjI+20Mf7i9euUSTRm9tm4N 6Aj75/d3+twJaQXX9i+8l2fPOa0yWpDhD5/Fmt2/eae3ffjtlnMlzHKSQcmfF4rxht73L+83197 UxQMA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 This header really makes little sense - every place it is included mm.h is also included, and the header itself includes mm.h, so it does nothing to reduce header size. It also oddly does an #ifdef around checking VMA_HUGETLB_BIT, however VMA_HUGETLB_BIT is unconditionally available, and will never be set if hugetlb is not enabled. Simply remove the header, eliminate the odd ifdeffery and place the predicates in mm.h. The naming of these predicates is odd, but to keep changes separate, we will address this in a separate patch. The file was never put into MAINTAINERS so there's no change required there. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- drivers/gpu/drm/drm_gpusvm.c | 2 +- include/asm-generic/tlb.h | 2 +- include/linux/hugetlb.h | 1 - include/linux/hugetlb_inline.h | 28 ---------------------------- include/linux/mm.h | 11 +++++++++++ include/linux/pagemap.h | 1 - include/linux/userfaultfd_k.h | 1 - kernel/sched/fair.c | 1 - mm/vma_internal.h | 1 - 9 files changed, 13 insertions(+), 35 deletions(-) diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c index a93eee7ddb9e..793dacec2100 100644 --- a/drivers/gpu/drm/drm_gpusvm.c +++ b/drivers/gpu/drm/drm_gpusvm.c @@ -9,9 +9,9 @@ #include #include #include -#include #include #include +#include #include =20 #include diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 044dabc1fe9c..8b8123e5b7d7 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -11,9 +11,9 @@ #ifndef _ASM_GENERIC__TLB_H #define _ASM_GENERIC__TLB_H =20 +#include #include #include -#include #include #include =20 diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 80a5a03e9cee..d7e6563cef75 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -7,7 +7,6 @@ #include #include #include -#include #include #include #include diff --git a/include/linux/hugetlb_inline.h b/include/linux/hugetlb_inline.h deleted file mode 100644 index 5c29cd3223a1..000000000000 --- a/include/linux/hugetlb_inline.h +++ /dev/null @@ -1,28 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _LINUX_HUGETLB_INLINE_H -#define _LINUX_HUGETLB_INLINE_H - -#include - -#ifdef CONFIG_HUGETLB_PAGE - -static inline bool is_vma_hugetlb_flags(const vma_flags_t *flags) -{ - return vma_flags_test(flags, VMA_HUGETLB_BIT); -} - -#else - -static inline bool is_vma_hugetlb_flags(const vma_flags_t *flags) -{ - return false; -} - -#endif - -static inline bool is_vm_hugetlb_page(const struct vm_area_struct *vma) -{ - return is_vma_hugetlb_flags(&vma->flags); -} - -#endif diff --git a/include/linux/mm.h b/include/linux/mm.h index 4b6aa0b47b00..726c2fee35fb 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1609,6 +1609,17 @@ static inline bool vma_is_shared_maywrite(const stru= ct vm_area_struct *vma) return is_shared_maywrite(&vma->flags); } =20 +static inline bool is_vma_hugetlb_flags(const vma_flags_t *flags) +{ + return IS_ENABLED(CONFIG_HUGETLB_PAGE) && + vma_flags_test(flags, VMA_HUGETLB_BIT); +} + +static inline bool is_vm_hugetlb_page(const struct vm_area_struct *vma) +{ + return is_vma_hugetlb_flags(&vma->flags); +} + /** * vma_flags_is_kernel_owned() - Do the specified VMA flags indicate that = the * contents of the VMA are owned by the kernel rather than the core mm? diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 939f3a5e973f..d7d8b312466c 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -14,7 +14,6 @@ #include #include #include /* for in_interrupt() */ -#include =20 struct folio_batch; =20 diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index a4351cffc60c..a14b8a9ffb7b 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -18,7 +18,6 @@ #include #include #include -#include =20 /* The set of all possible UFFD-related VM flags. */ #define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_MINOR | \ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a71f0ab79bcd..c75b5c50af30 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -22,7 +22,6 @@ */ #include #include -#include #include #include #include diff --git a/mm/vma_internal.h b/mm/vma_internal.h index 4d300e7bbaf4..4f73f0a4db79 100644 --- a/mm/vma_internal.h +++ b/mm/vma_internal.h @@ -18,7 +18,6 @@ #include #include #include -#include #include #include #include --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 A0EC93BB134; Mon, 14 Sep 2026 15:12:21 +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=1789398744; cv=none; b=L3K62/CNmmM/tgvLwiSje2u1ITHUlGQAVg+HZp/wwERg9hSPlbJ9I96pVbuUyTpkTefGr3lJOe5bW90y+2ybtdanh9LbtmKS8j26JommvT6+yrR99Ng3/R4RrgP7RhtU08JyIIRHCRHQuEnrjEm/2/NRwba00/Fa9QmhrOgsAiA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398744; c=relaxed/simple; bh=qARqi90cwAKxoQ+j/bXo33ypegrjdG46MzXfrvuR8mM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Kz9yoTaiLnQLE29G3IHUGY3DIJGwhEjObuQIywznhIO3gi2TmhnypcQsb5hqFZElSrVFm7NNCI1lr2Qoafd3LYd+rarT8Tv3ChJ1K/T+ps6Pxs0hmeT2aGI2DHl2flwfUq6qdbsqkUmWragqzUEJFoo1g6oEk0nVIwuX3k4UBPw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZPY6BSpm; 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="ZPY6BSpm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 352D31F000FF; Mon, 14 Sep 2026 15:11:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398741; bh=xmT7EJ4FkEyNpf9okvKMXTIbUmVHq8O1x430QgTIUHI=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=ZPY6BSpmgmNxto7Q9dsbj/PcymY+GrF3IfhJxwc48cklECWFwX8OUsuNY5uQ9r/06 vFs1WPzP/EMVGdPUrXr4iQg1nNHAvxJoUaV5DlzvVFtlT1W36EWEAE7g+uxTjU9uVy jSyNLBcaugTzQclrHmhQ2u3f59YWf/eZ5sDuB9Ml7oFO3FNOm0jXTb2yWSE1RIVYHn 9SdNgH5I1zm0Fdd0Gku6m2d2vKu71eZCahgFi2CxIAQZT1D0U7TUSh22iJTyRBjcg3 ZwYvEt4zoMLNRA8+nIWEsvEqMCgkf7mjXR5/3ru/trYR5zC/5BV0TS9Ha8sw3oMtdi hqBXM6yzWX/xg== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:48 +0100 Subject: [PATCH v2 28/40] mm: rename is_vm_hugetlb_page() to vma_is_hugetlb() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-28-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> To: Andrew Morton , "Liam R. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=33992; i=ljs@kernel.org; h=from:subject:message-id; bh=qARqi90cwAKxoQ+j/bXo33ypegrjdG46MzXfrvuR8mM=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG+6aPLfUvr0MTHn5OUvTlZMsBF/sXCv4zfleBXpy IRz/AUnO0pZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjARp6MM/1RWrC6KaXrJOnGF 0eG1Isd26JRMOfzmEa/UlXs9GmmOnHcZ/vCKrw7Wnv/2d8z/AzuP7+/dbPiiW8PuhpBw4bL0gNc HRFkB X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 The is_vm_hugetlb_page() predicate is badly named - the mapping can span more than a page and it is inconsistent with other VMA predicates that typically are prefixed by vma_. Rename to vma_is_hugetlb() for consistency, and while we're here update some VM_BUG_ON_VMA() to VM_WARN_ON_ONCE_VMA() as to avoid unnecessary oopses. No functional change intended. Acked-by: Marc Zyngier Acked-by: Claudio Imbrenda Acked-by: Anup Patel Signed-off-by: Lorenzo Stoakes (ARM) --- arch/arm64/kvm/mmu.c | 4 ++-- arch/powerpc/mm/book3s64/radix_tlb.c | 6 +++--- arch/powerpc/mm/nohash/e500_hugetlbpage.c | 2 +- arch/powerpc/mm/nohash/tlb.c | 2 +- arch/riscv/kvm/mmu.c | 2 +- arch/riscv/mm/tlbflush.c | 2 +- arch/s390/mm/gmap_helpers.c | 6 +++--- arch/sparc/mm/init_64.c | 2 +- drivers/gpu/drm/drm_gpusvm.c | 2 +- fs/coredump.c | 2 +- fs/hugetlbfs/inode.c | 2 +- fs/proc/task_mmu.c | 8 ++++---- include/asm-generic/tlb.h | 2 +- include/linux/hugetlb.h | 4 ++-- include/linux/mm.h | 19 ++++++++++++++++--- include/linux/rmap.h | 2 +- kernel/events/core.c | 2 +- kernel/sched/fair.c | 2 +- mm/gup.c | 4 ++-- mm/huge_memory.c | 2 +- mm/hugetlb.c | 14 +++++++------- mm/internal.h | 2 +- mm/madvise.c | 4 ++-- mm/memory.c | 12 ++++++------ mm/mempolicy.c | 2 +- mm/migrate_device.c | 2 +- mm/mmap.c | 2 +- mm/mmu_gather.c | 2 +- mm/mprotect.c | 2 +- mm/mremap.c | 6 +++--- mm/page_vma_mapped.c | 4 ++-- mm/pagewalk.c | 2 +- mm/swapfile.c | 2 +- mm/userfaultfd.c | 26 +++++++++++++------------- mm/vma.c | 8 ++++---- mm/vmscan.c | 2 +- tools/testing/vma/include/stubs.h | 2 +- 37 files changed, 92 insertions(+), 79 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 9ba86450fe4a..a7968f8d24bf 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1463,13 +1463,13 @@ static int get_vma_page_shift(struct vm_area_struct= *vma, unsigned long hva) { unsigned long pa; =20 - if (is_vm_hugetlb_page(vma) && !(vma->vm_flags & VM_PFNMAP)) + if (vma_is_hugetlb(vma) && !(vma->vm_flags & VM_PFNMAP)) return huge_page_shift(hstate_vma(vma)); =20 if (!(vma->vm_flags & VM_PFNMAP)) return PAGE_SHIFT; =20 - VM_BUG_ON(is_vm_hugetlb_page(vma)); + VM_BUG_ON(vma_is_hugetlb(vma)); =20 pa =3D (vma->vm_pgoff << PAGE_SHIFT) + (hva - vma->vm_start); =20 diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s6= 4/radix_tlb.c index 7de5760164a9..b4603a98224b 100644 --- a/arch/powerpc/mm/book3s64/radix_tlb.c +++ b/arch/powerpc/mm/book3s64/radix_tlb.c @@ -627,7 +627,7 @@ void radix__local_flush_tlb_page(struct vm_area_struct = *vma, unsigned long vmadd { #ifdef CONFIG_HUGETLB_PAGE /* need the return fix for nohash.c */ - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) return radix__local_flush_hugetlb_page(vma, vmaddr); #endif radix__local_flush_tlb_page_psize(vma->vm_mm, vmaddr, mmu_virtual_psize); @@ -945,7 +945,7 @@ void radix__flush_tlb_page_psize(struct mm_struct *mm, = unsigned long vmaddr, void radix__flush_tlb_page(struct vm_area_struct *vma, unsigned long vmadd= r) { #ifdef CONFIG_HUGETLB_PAGE - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) return radix__flush_hugetlb_page(vma, vmaddr); #endif radix__flush_tlb_page_psize(vma->vm_mm, vmaddr, mmu_virtual_psize); @@ -1113,7 +1113,7 @@ void radix__flush_tlb_range(struct vm_area_struct *vm= a, unsigned long start, =20 { #ifdef CONFIG_HUGETLB_PAGE - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) return radix__flush_hugetlb_tlb_range(vma, start, end); #endif =20 diff --git a/arch/powerpc/mm/nohash/e500_hugetlbpage.c b/arch/powerpc/mm/no= hash/e500_hugetlbpage.c index a134d28a0e4d..b87623f04be5 100644 --- a/arch/powerpc/mm/nohash/e500_hugetlbpage.c +++ b/arch/powerpc/mm/nohash/e500_hugetlbpage.c @@ -180,7 +180,7 @@ book3e_hugetlb_preload(struct vm_area_struct *vma, unsi= gned long ea, pte_t pte) */ void __update_mmu_cache(struct vm_area_struct *vma, unsigned long address,= pte_t *ptep) { - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) book3e_hugetlb_preload(vma, address, *ptep); } =20 diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c index 0a650742f3a0..07a2db16c2b1 100644 --- a/arch/powerpc/mm/nohash/tlb.c +++ b/arch/powerpc/mm/nohash/tlb.c @@ -278,7 +278,7 @@ void __flush_tlb_page(struct mm_struct *mm, unsigned lo= ng vmaddr, void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr) { #ifdef CONFIG_HUGETLB_PAGE - if (vma && is_vm_hugetlb_page(vma)) + if (vma && vma_is_hugetlb(vma)) flush_hugetlb_page(vma, vmaddr); #endif =20 diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index 6035b5ec9503..5c5c77f98bf0 100644 --- a/arch/riscv/kvm/mmu.c +++ b/arch/riscv/kvm/mmu.c @@ -664,7 +664,7 @@ int kvm_riscv_mmu_map(struct kvm_vcpu *vcpu, struct kvm= _memory_slot *memslot, return -EFAULT; } =20 - is_hugetlb =3D is_vm_hugetlb_page(vma); + is_hugetlb =3D vma_is_hugetlb(vma); if (is_hugetlb) vma_pageshift =3D huge_page_shift(hstate_vma(vma)); else diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c index 962db300a166..a74a7d5258aa 100644 --- a/arch/riscv/mm/tlbflush.c +++ b/arch/riscv/mm/tlbflush.c @@ -149,7 +149,7 @@ void flush_tlb_range(struct vm_area_struct *vma, unsign= ed long start, { unsigned long stride_size; =20 - if (!is_vm_hugetlb_page(vma)) { + if (!vma_is_hugetlb(vma)) { stride_size =3D PAGE_SIZE; } else { stride_size =3D huge_page_size(hstate_vma(vma)); diff --git a/arch/s390/mm/gmap_helpers.c b/arch/s390/mm/gmap_helpers.c index ff63ffb1dbd2..3f6783b93e67 100644 --- a/arch/s390/mm/gmap_helpers.c +++ b/arch/s390/mm/gmap_helpers.c @@ -102,7 +102,7 @@ __context_unsafe(/* pte_unmap_unlock() not instrumented= */) =20 /* Find the vm address for the guest address */ vma =3D vma_lookup(mm, vmaddr); - if (!vma || is_vm_hugetlb_page(vma)) + if (!vma || vma_is_hugetlb(vma)) return; =20 /* Get pointer to the page table entry */ @@ -139,7 +139,7 @@ void gmap_helper_discard(struct mm_struct *mm, unsigned= long vmaddr, unsigned lo vma =3D find_vma_intersection(mm, vmaddr, end); if (!vma) return; - if (!is_vm_hugetlb_page(vma)) + if (!vma_is_hugetlb(vma)) zap_vma_range(vma, vmaddr, min(end, vma->vm_end) - vmaddr); vmaddr =3D vma->vm_end; } @@ -247,7 +247,7 @@ static int __gmap_helper_unshare_zeropages(struct mm_st= ruct *mm) * proof to catch unexpected zeropages in other mappings and * fail. */ - if ((vma->vm_flags & VM_PFNMAP) || is_vm_hugetlb_page(vma)) + if ((vma->vm_flags & VM_PFNMAP) || vma_is_hugetlb(vma)) continue; addr =3D vma->vm_start; =20 diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index 103db4683b16..9bbccb5d23a8 100644 --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -413,7 +413,7 @@ void update_mmu_cache_range(struct vm_fault *vmf, struc= t vm_area_struct *vma, if (mm->context.hugetlb_pte_count || mm->context.thp_pte_count) { unsigned long hugepage_size =3D PAGE_SIZE; =20 - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) hugepage_size =3D huge_page_size(hstate_vma(vma)); =20 if (hugepage_size >=3D PUD_SIZE) { diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c index 793dacec2100..a1d4989b0b61 100644 --- a/drivers/gpu/drm/drm_gpusvm.c +++ b/drivers/gpu/drm/drm_gpusvm.c @@ -1142,7 +1142,7 @@ drm_gpusvm_range_find_or_insert(struct drm_gpusvm *gp= usvm, * have to change. */ migrate_devmem =3D ctx->devmem_possible && - vma_is_anonymous(vas) && !is_vm_hugetlb_page(vas); + vma_is_anonymous(vas) && !vma_is_hugetlb(vas); =20 chunk_size =3D drm_gpusvm_range_chunk_size(gpusvm, notifier, vas, fault_addr, gpuva_start, diff --git a/fs/coredump.c b/fs/coredump.c index ac3cd74808c6..fb21fb6703dd 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1608,7 +1608,7 @@ static unsigned long vma_dump_size(struct vm_area_str= uct *vma, } =20 /* Hugetlb memory check */ - if (is_vm_hugetlb_page(vma)) { + if (vma_is_hugetlb(vma)) { if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) goto whole; if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE)) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 7611a8470ea2..ba7097d5720c 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -108,7 +108,7 @@ static int hugetlbfs_file_mmap(struct file *file, struc= t vm_area_struct *vma) * vma address alignment (but not the pgoff alignment) has * already been checked by prepare_hugepage_range. If you add * any error returns here, do so after setting VM_HUGETLB, so - * is_vm_hugetlb_page tests below unmap_region go the right + * vma_is_hugetlb tests below unmap_region go the right * way when do_mmap unwinds (may be important on powerpc * and ia64). */ diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index e671b4fd8ded..565e6446bd31 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -3015,7 +3015,7 @@ static int pagemap_scan_pte_hole(unsigned long addr, = unsigned long end, * hugetlb differs, see pagemap_hugetlb_category(). */ categories =3D p->cur_vma_category; - if (userfaultfd_wp(vma) && !is_vm_hugetlb_page(vma)) + if (userfaultfd_wp(vma) && !vma_is_hugetlb(vma)) categories |=3D PAGE_IS_WRITTEN; =20 if (!pagemap_scan_is_interesting_page(categories, p)) @@ -3028,7 +3028,7 @@ static int pagemap_scan_pte_hole(unsigned long addr, = unsigned long end, if (~p->arg.flags & PM_SCAN_WP_MATCHING) return ret; =20 - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) err =3D pagemap_scan_hugetlb_hole_wp(vma, addr, end); else err =3D uffd_wp_range(vma, addr, end - addr, true); @@ -3470,7 +3470,7 @@ static int show_numa_map(struct seq_file *m, void *v) seq_puts(m, " stack"); } =20 - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) seq_puts(m, " huge"); =20 /* Skip walking pages if gate VMA */ @@ -3499,7 +3499,7 @@ static int show_numa_map(struct seq_file *m, void *v) if (md->swapcache) seq_printf(m, " swapcache=3D%lu", md->swapcache); =20 - if (md->active < md->pages && !is_vm_hugetlb_page(vma)) + if (md->active < md->pages && !vma_is_hugetlb(vma)) seq_printf(m, " active=3D%lu", md->active); =20 if (md->writeback) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 8b8123e5b7d7..48d47b34cc77 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -438,7 +438,7 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_= area_struct *vma) * We rely on tlb_end_vma() to issue a flush, such that when we reset * these values the batch is empty. */ - tlb->vma_huge =3D is_vm_hugetlb_page(vma); + tlb->vma_huge =3D vma_is_hugetlb(vma); tlb->vma_exec =3D !!(vma->vm_flags & VM_EXEC); =20 /* diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index d7e6563cef75..24727ece20fe 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -251,14 +251,14 @@ extern void __hugetlb_zap_end(struct vm_area_struct *= vma, static inline void hugetlb_zap_begin(struct vm_area_struct *vma, unsigned long *start, unsigned long *end) { - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) __hugetlb_zap_begin(vma, start, end); } =20 static inline void hugetlb_zap_end(struct vm_area_struct *vma, struct zap_details *details) { - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) __hugetlb_zap_end(vma, details); } =20 diff --git a/include/linux/mm.h b/include/linux/mm.h index 726c2fee35fb..154fc25c9efa 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1609,15 +1609,28 @@ static inline bool vma_is_shared_maywrite(const str= uct vm_area_struct *vma) return is_shared_maywrite(&vma->flags); } =20 -static inline bool is_vma_hugetlb_flags(const vma_flags_t *flags) +/** + * vma_flags_is_hugetlb() - Do the specified VMA flags indicate that the + * VMA is a hugetlb mapping? + * @flags: The VMA flags to test. + * + * Returns: true if the flags indicate a hugetlb mapping, false otherwise. + */ +static inline bool vma_flags_is_hugetlb(const vma_flags_t *flags) { return IS_ENABLED(CONFIG_HUGETLB_PAGE) && vma_flags_test(flags, VMA_HUGETLB_BIT); } =20 -static inline bool is_vm_hugetlb_page(const struct vm_area_struct *vma) +/** + * vma_is_hugetlb() - Is @vma a hugetlb mapping? + * @vma: The VMA to test. + * + * Returns: true if @vma is a hugetlb mapping, false otherwise. + */ +static inline bool vma_is_hugetlb(const struct vm_area_struct *vma) { - return is_vma_hugetlb_flags(&vma->flags); + return vma_flags_is_hugetlb(&vma->flags); } =20 /** diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 0b332770abee..74cca0e3c726 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -888,7 +888,7 @@ struct page_vma_mapped_walk { static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *= pvmw) { /* HugeTLB pte is set to the relevant page table entry without pte_mapped= . */ - if (pvmw->pte && !is_vm_hugetlb_page(pvmw->vma)) + if (pvmw->pte && !vma_is_hugetlb(pvmw->vma)) pte_unmap(pvmw->pte); if (pvmw->ptl) spin_unlock(pvmw->ptl); diff --git a/kernel/events/core.c b/kernel/events/core.c index a6c8e38a3110..8ca8a6842924 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9808,7 +9808,7 @@ static void perf_event_mmap_event(struct perf_mmap_ev= ent *mmap_event) =20 if (vma->vm_flags & VM_LOCKED) flags |=3D MAP_LOCKED; - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) flags |=3D MAP_HUGETLB; =20 if (file) { diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c75b5c50af30..ae6c1a606eb5 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4211,7 +4211,7 @@ static void task_numa_work(struct callback_head *work) =20 for (; vma; vma =3D vma_next(&vmi)) { if (!vma_migratable(vma) || !vma_policy_mof(vma) || - is_vm_hugetlb_page(vma) || vma_is_kernel_owned(vma)) { + vma_is_hugetlb(vma) || vma_is_kernel_owned(vma)) { trace_sched_skip_vma_numa(mm, vma, NUMAB_SKIP_UNSUITABLE); continue; } diff --git a/mm/gup.c b/mm/gup.c index e6310a7cc05b..f166acf794e3 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -621,7 +621,7 @@ static struct page *no_page_table(struct vm_area_struct= *vma, * But we can only make this optimization where a hole would surely * be zero-filled if handle_mm_fault() actually did handle it. */ - if (is_vm_hugetlb_page(vma)) { + if (vma_is_hugetlb(vma)) { struct hstate *h =3D hstate_vma(vma); =20 if (!hugetlbfs_pagecache_present(h, vma, address)) @@ -1213,7 +1213,7 @@ static int check_vma_flags(struct vm_area_struct *vma= , unsigned long gup_flags) if ((gup_flags & FOLL_LONGTERM) && vma_is_fsdax(vma)) return -EOPNOTSUPP; =20 - if ((gup_flags & FOLL_SPLIT_PMD) && is_vm_hugetlb_page(vma)) + if ((gup_flags & FOLL_SPLIT_PMD) && vma_is_hugetlb(vma)) return -EOPNOTSUPP; =20 if (vma_is_secretmem(vma)) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 4d0acd9a1099..c3c98ea672c3 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -4769,7 +4769,7 @@ static inline bool vma_not_suitable_for_thp_split(str= uct vm_area_struct *vma) return true; if (vma_test(vma, VMA_IO_BIT)) return true; - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) return true; =20 return false; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d3a0650ff690..817f57f13b09 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1147,7 +1147,7 @@ static inline struct resv_map *inode_resv_map(struct = inode *inode) =20 static struct resv_map *vma_resv_map(struct vm_area_struct *vma) { - VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); + VM_WARN_ON_ONCE_VMA(!vma_is_hugetlb(vma), vma); if (vma->vm_flags & VM_MAYSHARE) { struct address_space *mapping =3D vma->vm_file->f_mapping; struct inode *inode =3D mapping->host; @@ -1162,7 +1162,7 @@ static struct resv_map *vma_resv_map(struct vm_area_s= truct *vma) =20 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *= map) { - VM_WARN_ON_ONCE_VMA(!is_vm_hugetlb_page(vma), vma); + VM_WARN_ON_ONCE_VMA(!vma_is_hugetlb(vma), vma); VM_WARN_ON_ONCE_VMA(vma_test(vma, VMA_MAYSHARE_BIT), vma); =20 set_vma_private_data(vma, (unsigned long)map); @@ -1170,7 +1170,7 @@ static void set_vma_resv_map(struct vm_area_struct *v= ma, struct resv_map *map) =20 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long f= lags) { - VM_WARN_ON_ONCE_VMA(!is_vm_hugetlb_page(vma), vma); + VM_WARN_ON_ONCE_VMA(!vma_is_hugetlb(vma), vma); VM_WARN_ON_ONCE_VMA(vma_test(vma, VMA_MAYSHARE_BIT), vma); =20 set_vma_private_data(vma, get_vma_private_data(vma) | flags); @@ -1178,7 +1178,7 @@ static void set_vma_resv_flags(struct vm_area_struct = *vma, unsigned long flags) =20 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) { - VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); + VM_WARN_ON_ONCE_VMA(!vma_is_hugetlb(vma), vma); =20 return (get_vma_private_data(vma) & flag) !=3D 0; } @@ -1192,7 +1192,7 @@ bool __vma_private_lock(struct vm_area_struct *vma) =20 void hugetlb_dup_vma_private(struct vm_area_struct *vma) { - VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); + VM_WARN_ON_ONCE_VMA(!vma_is_hugetlb(vma), vma); /* * Clear vm_private_data * - For shared mappings this is a per-vma semaphore that may be @@ -5279,7 +5279,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, s= truct vm_area_struct *vma, unsigned long last_addr_mask; =20 i_mmap_assert_write_locked(vma->vm_file->f_mapping); - WARN_ON(!is_vm_hugetlb_page(vma)); + WARN_ON(!vma_is_hugetlb(vma)); BUG_ON(start & ~huge_page_mask(h)); BUG_ON(end & ~huge_page_mask(h)); =20 @@ -7505,6 +7505,6 @@ void hugetlb_unshare_all_pmds(struct vm_area_struct *= vma) */ void fixup_hugetlb_reservations(struct vm_area_struct *vma) { - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) clear_vma_resv_huge_pages(vma); } diff --git a/mm/internal.h b/mm/internal.h index 59cfe336e468..1b6153013061 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1115,7 +1115,7 @@ static inline bool vma_supports_mlock(const struct vm= _area_struct *vma) return false; if (vma_test_single_mask(vma, VMA_DROPPABLE)) return false; - if (vma_is_dax(vma) || is_vm_hugetlb_page(vma)) + if (vma_is_dax(vma) || vma_is_hugetlb(vma)) return false; return vma !=3D get_gate_vma(current->mm); } diff --git a/mm/madvise.c b/mm/madvise.c index fbb72ab49aa6..467601a8525b 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -881,7 +881,7 @@ bool madvise_dontneed_free_valid_vma(struct madvise_beh= avior *madv_behavior) int behavior =3D madv_behavior->behavior; struct madvise_behavior_range *range =3D &madv_behavior->range; =20 - if (!is_vm_hugetlb_page(vma)) { + if (!vma_is_hugetlb(vma)) { unsigned int forbidden =3D VM_PFNMAP; =20 if (behavior !=3D MADV_DONTNEED_LOCKED) @@ -1578,7 +1578,7 @@ static int madvise_vma_behavior(struct madvise_behavi= or *madv_behavior) new_flags |=3D VM_DONTDUMP; break; case MADV_DODUMP: - if ((!is_vm_hugetlb_page(vma) && (new_flags & VM_SPECIAL)) || + if ((!vma_is_hugetlb(vma) && (new_flags & VM_SPECIAL)) || (new_flags & VM_DROPPABLE)) return -EINVAL; new_flags &=3D ~VM_DONTDUMP; diff --git a/mm/memory.c b/mm/memory.c index 38fe455dc70c..02e9d5d2e279 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1564,7 +1564,7 @@ copy_page_range(struct vm_area_struct *dst_vma, struc= t vm_area_struct *src_vma) if (!vma_needs_copy(dst_vma, src_vma)) return 0; =20 - if (is_vm_hugetlb_page(src_vma)) + if (vma_is_hugetlb(src_vma)) return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma); =20 /* @@ -2178,7 +2178,7 @@ static void __zap_vma_range(struct mmu_gather *tlb, s= truct vm_area_struct *vma, if (vma->vm_file && !reaping) uprobe_munmap(vma, start, end); =20 - if (unlikely(is_vm_hugetlb_page(vma))) { + if (unlikely(vma_is_hugetlb(vma))) { zap_flags_t zap_flags =3D details ? details->zap_flags : 0; =20 VM_WARN_ON_ONCE(reaping); @@ -2313,7 +2313,7 @@ void zap_vma_range_batched(struct mmu_gather *tlb, */ __zap_vma_range(tlb, vma, address, end, details); mmu_notifier_invalidate_range_end(&range); - if (is_vm_hugetlb_page(vma)) { + if (vma_is_hugetlb(vma)) { /* * flush tlb and free resources before hugetlb_zap_end(), to * avoid concurrent page faults' allocation failure. @@ -6933,7 +6933,7 @@ vm_fault_t handle_mm_fault(struct vm_area_struct *vma= , unsigned long address, =20 lru_gen_enter_fault(vma); =20 - if (unlikely(is_vm_hugetlb_page(vma))) + if (unlikely(vma_is_hugetlb(vma))) ret =3D hugetlb_fault(vma->vm_mm, vma, address, flags); else ret =3D __handle_mm_fault(vma, address, flags); @@ -7803,12 +7803,12 @@ void ptlock_free(struct ptdesc *ptdesc) =20 void vma_pgtable_walk_begin(struct vm_area_struct *vma) { - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) hugetlb_vma_lock_read(vma); } =20 void vma_pgtable_walk_end(struct vm_area_struct *vma) { - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) hugetlb_vma_unlock_read(vma); } diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 8fc8a975657e..044ffb4f4128 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2023,7 +2023,7 @@ bool vma_migratable(struct vm_area_struct *vma) if (vma_is_dax(vma)) return false; =20 - if (is_vm_hugetlb_page(vma) && + if (vma_is_hugetlb(vma) && !hugepage_migration_supported(hstate_vma(vma))) return false; =20 diff --git a/mm/migrate_device.c b/mm/migrate_device.c index 0c437004329d..c38cbaaef5a4 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -743,7 +743,7 @@ int migrate_vma_setup(struct migrate_vma *args) =20 args->start &=3D PAGE_MASK; args->end &=3D PAGE_MASK; - if (!args->vma || is_vm_hugetlb_page(args->vma) || + if (!args->vma || vma_is_hugetlb(args->vma) || (args->vma->vm_flags & VM_SPECIAL) || vma_is_dax(args->vma)) return -EINVAL; if (nr_pages <=3D 0) diff --git a/mm/mmap.c b/mm/mmap.c index 4bf26b0f1e6e..98449f364af1 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1786,7 +1786,7 @@ __latent_entropy int dup_mmap(struct mm_struct *mm, s= truct mm_struct *oldmm) /* * Copy/update hugetlb private vma information. */ - if (is_vm_hugetlb_page(tmp)) + if (vma_is_hugetlb(tmp)) hugetlb_dup_vma_private(tmp); =20 /* diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c index 2a72a9686773..9f353f0e2ef4 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -480,7 +480,7 @@ void tlb_gather_mmu_vma(struct mmu_gather *tlb, struct = vm_area_struct *vma) { tlb_gather_mmu(tlb, vma->vm_mm); tlb_update_vma_flags(tlb, vma); - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) /* All entries have the same size. */ tlb_change_page_size(tlb, huge_page_size(hstate_vma(vma))); } diff --git a/mm/mprotect.c b/mm/mprotect.c index fe32fd87cf5c..a1b6d29bf039 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -717,7 +717,7 @@ long change_protection(struct mmu_gather *tlb, (cp_flags & MM_CP_UFFD_RWP)) newprot =3D PAGE_NONE; =20 - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) pages =3D hugetlb_change_protection(vma, start, end, newprot, cp_flags); else diff --git a/mm/mremap.c b/mm/mremap.c index ed19b47c2caf..1122282a1d6a 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -812,7 +812,7 @@ unsigned long move_page_tables(struct pagetable_move_co= ntrol *pmc) if (!pmc->len_in) return 0; =20 - if (is_vm_hugetlb_page(pmc->old)) + if (vma_is_hugetlb(pmc->old)) return move_hugetlb_page_tables(pmc->old, pmc->new, pmc->old_addr, pmc->new_addr, pmc->len_in); =20 @@ -1735,7 +1735,7 @@ static bool vma_multi_allowed(struct vm_area_struct *= vma) /* Known good. */ if (vma_is_shmem(vma)) return true; - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) return true; if (file->f_op->get_unmapped_area =3D=3D thp_get_unmapped_area) return true; @@ -1758,7 +1758,7 @@ static int check_prep_vma(struct vma_remap_struct *vr= m) return -EPERM; =20 /* Align to hugetlb page size, if required. */ - if (is_vm_hugetlb_page(vma) && !align_hugetlb(vrm)) + if (vma_is_hugetlb(vma) && !align_hugetlb(vrm)) return -EINVAL; =20 vrm_set_delta(vrm); diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 28e306fdb3a5..8408aee7571b 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -109,7 +109,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw= , unsigned long pte_nr) unsigned long pfn; pte_t ptent; =20 - if (is_vm_hugetlb_page(pvmw->vma)) + if (vma_is_hugetlb(pvmw->vma)) ptent =3D huge_ptep_get(pvmw->vma->vm_mm, pvmw->address, pvmw->pte); else @@ -206,7 +206,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *= pvmw) if (pvmw->pmd && !pvmw->pte) return not_found(pvmw); =20 - if (unlikely(is_vm_hugetlb_page(vma))) { + if (unlikely(vma_is_hugetlb(vma))) { struct hstate *hstate =3D hstate_vma(vma); unsigned long size =3D huge_page_size(hstate); /* The only possible mapping was handled on last iteration */ diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 7411702a37f5..e6493bbe6919 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -408,7 +408,7 @@ static int __walk_page_range(unsigned long start, unsig= ned long end, int err =3D 0; struct vm_area_struct *vma =3D walk->vma; const struct mm_walk_ops *ops =3D walk->ops; - bool is_hugetlb =3D is_vm_hugetlb_page(vma); + bool is_hugetlb =3D vma_is_hugetlb(vma); =20 /* We do not support hugetlb PTE installation. */ if (ops->install_pte && is_hugetlb) diff --git a/mm/swapfile.c b/mm/swapfile.c index 2cd0d0ba966c..c1c5fbb3c909 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2707,7 +2707,7 @@ static int unuse_mm(struct mm_struct *mm, unsigned in= t type) if (check_stable_address_space(mm)) goto unlock; for_each_vma(vmi, vma) { - if (vma->anon_vma && !is_vm_hugetlb_page(vma)) { + if (vma->anon_vma && !vma_is_hugetlb(vma)) { ret =3D unuse_vma(vma, type); if (ret) break; diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 79cc7b546f13..949017e60608 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -237,7 +237,7 @@ static int mfill_get_vma(struct mfill_state *state) if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP)) goto out_unlock; =20 - if (is_vm_hugetlb_page(dst_vma)) + if (vma_is_hugetlb(dst_vma)) return 0; =20 ops =3D vma_uffd_ops(dst_vma); @@ -804,7 +804,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb( } =20 err =3D -ENOENT; - if (!is_vm_hugetlb_page(dst_vma)) + if (!vma_is_hugetlb(dst_vma)) goto out_unlock_vma; =20 err =3D -EINVAL; @@ -967,7 +967,7 @@ static __always_inline ssize_t mfill_atomic(struct user= faultfd_ctx *ctx, /* * If this is a HUGETLB vma, pass off to appropriate routine */ - if (is_vm_hugetlb_page(state.vma)) + if (vma_is_hugetlb(state.vma)) return mfill_atomic_hugetlb(ctx, state.vma, dst_start, src_start, len, flags); =20 @@ -1114,7 +1114,7 @@ static int mwriteprotect_range(struct userfaultfd_ctx= *ctx, unsigned long start, break; } =20 - if (is_vm_hugetlb_page(dst_vma)) { + if (vma_is_hugetlb(dst_vma)) { err =3D -EINVAL; page_mask =3D vma_kernel_pagesize(dst_vma) - 1; if ((start & page_mask) || (len & page_mask)) @@ -1172,7 +1172,7 @@ int mrwprotect_range(struct userfaultfd_ctx *ctx, uns= igned long start, if (!userfaultfd_rwp(dst_vma)) return -ENOENT; =20 - if (is_vm_hugetlb_page(dst_vma)) { + if (vma_is_hugetlb(dst_vma)) { unsigned long page_mask; =20 page_mask =3D vma_kernel_pagesize(dst_vma) - 1; @@ -2149,7 +2149,7 @@ static bool vma_can_userfault(struct vm_area_struct *= vma, vm_flags_t vm_flags, if (vma->vm_flags & (VM_DROPPABLE | VM_SHADOW_STACK)) return false; =20 - if (!is_vm_hugetlb_page(vma) && (vma->vm_flags & VM_SPECIAL)) + if (!vma_is_hugetlb(vma) && (vma->vm_flags & VM_SPECIAL)) return false; =20 vm_flags &=3D __VM_UFFD_FLAGS; @@ -2319,7 +2319,7 @@ static int userfaultfd_register_range(struct userfaul= tfd_ctx *ctx, */ userfaultfd_set_ctx(vma, ctx, vm_flags); =20 - if (is_vm_hugetlb_page(vma) && uffd_disable_huge_pmd_share(vma)) + if (vma_is_hugetlb(vma) && uffd_disable_huge_pmd_share(vma)) hugetlb_unshare_all_pmds(vma); =20 skip: @@ -2895,7 +2895,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, uns= igned long reason) * (sleepable) vma lock can modify the current task state, that * must be before explicitly calling set_current_state(). */ - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) hugetlb_vma_lock_read(vma); =20 spin_lock_irq(&ctx->fault_pending_wqh.lock); @@ -2912,7 +2912,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, uns= igned long reason) set_current_state(blocking_state); spin_unlock_irq(&ctx->fault_pending_wqh.lock); =20 - if (is_vm_hugetlb_page(vma)) { + if (vma_is_hugetlb(vma)) { must_wait =3D userfaultfd_huge_must_wait(ctx, vmf, reason); hugetlb_vma_unlock_read(vma); } else { @@ -3744,7 +3744,7 @@ static int userfaultfd_register(struct userfaultfd_ct= x *ctx, * If the first vma contains huge pages, make sure start address * is aligned to huge page size. */ - if (is_vm_hugetlb_page(vma)) { + if (vma_is_hugetlb(vma)) { unsigned long vma_hpagesize =3D vma_kernel_pagesize(vma); =20 if (start & (vma_hpagesize - 1)) @@ -3795,7 +3795,7 @@ static int userfaultfd_register(struct userfaultfd_ct= x *ctx, * If this vma contains ending address, and huge pages * check alignment. */ - if (is_vm_hugetlb_page(cur) && end <=3D cur->vm_end && + if (vma_is_hugetlb(cur) && end <=3D cur->vm_end && end > cur->vm_start) { unsigned long vma_hpagesize =3D vma_kernel_pagesize(cur); =20 @@ -3831,7 +3831,7 @@ static int userfaultfd_register(struct userfaultfd_ct= x *ctx, /* * Note vmas containing huge pages */ - if (is_vm_hugetlb_page(cur)) + if (vma_is_hugetlb(cur)) basic_ioctls =3D true; =20 found =3D true; @@ -3917,7 +3917,7 @@ static int userfaultfd_unregister(struct userfaultfd_= ctx *ctx, * If the first vma contains huge pages, make sure start address * is aligned to huge page size. */ - if (is_vm_hugetlb_page(vma)) { + if (vma_is_hugetlb(vma)) { unsigned long vma_hpagesize =3D vma_kernel_pagesize(vma); =20 if (start & (vma_hpagesize - 1)) diff --git a/mm/vma.c b/mm/vma.c index 54e5f4bbd8af..777656306705 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -599,7 +599,7 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_st= ruct *vma, * boundary. */ vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL); - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) hugetlb_split(vma, addr); =20 if (new_below) { @@ -2236,7 +2236,7 @@ bool vma_wants_writenotify(struct vm_area_struct *vma= , pgprot_t vm_page_prot) * Do we need to track softdirty? hugetlb does not support softdirty * tracking yet. */ - if (vma_soft_dirty_enabled(vma) && !is_vm_hugetlb_page(vma)) + if (vma_soft_dirty_enabled(vma) && !vma_is_hugetlb(vma)) return true; =20 /* Do we need write faults for uffd-wp tracking? */ @@ -2355,7 +2355,7 @@ int mm_take_all_locks(struct mm_struct *mm) if (signal_pending(current)) goto out_unlock; if (vma->vm_file && vma->vm_file->f_mapping && - is_vm_hugetlb_page(vma)) + vma_is_hugetlb(vma)) vm_lock_mapping(mm, vma->vm_file->f_mapping); } =20 @@ -2364,7 +2364,7 @@ int mm_take_all_locks(struct mm_struct *mm) if (signal_pending(current)) goto out_unlock; if (vma->vm_file && vma->vm_file->f_mapping && - !is_vm_hugetlb_page(vma)) + !vma_is_hugetlb(vma)) vm_lock_mapping(mm, vma->vm_file->f_mapping); } =20 diff --git a/mm/vmscan.c b/mm/vmscan.c index aaceed4759ee..12ed3388ee41 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3471,7 +3471,7 @@ static int should_skip_vma(unsigned long start, unsig= ned long end, struct mm_wal if (!vma_is_accessible(vma)) return true; =20 - if (is_vm_hugetlb_page(vma)) + if (vma_is_hugetlb(vma)) return true; =20 if (!vma_has_recency(vma)) diff --git a/tools/testing/vma/include/stubs.h b/tools/testing/vma/include/= stubs.h index d6136e19a8af..48d1dc53df42 100644 --- a/tools/testing/vma/include/stubs.h +++ b/tools/testing/vma/include/stubs.h @@ -193,7 +193,7 @@ static inline bool mapping_can_writeback(struct address= _space *mapping) return true; } =20 -static inline bool is_vm_hugetlb_page(struct vm_area_struct *vma) +static inline bool vma_is_hugetlb(struct vm_area_struct *vma) { return false; } --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 7A849489FA3; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jFlaAQin" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 048671F00893; Mon, 14 Sep 2026 15:12:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398769; bh=tN13W6jwJWnvYLjX7TO8ZRd5JDwmaJZiUPNzCgrQU0E=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=jFlaAQin+oAtoOa1M4DSIw9dAIP1iSZp2pLTn+auqN0GfEe/JXNztKg+WFdsuRXfI OUTf1CRcPeeG0tlNXiyIn+ZRVBA3x7SlMgG8LtvwO5vUMvTfQI4bBiWBDGu07spVOD e7GAN02gmQHUG23bXpH6nR0nzNnP0g/RoYb84GuB3Jk5EPN4xZtGjiUrTZfUrFDUqJ kkuAbhmPIfk9VWrrttWwXpUM5QybzXe5cyFv2kPQ2BVvWg772oGhx4ttklCTr0HF87 27T/S546CBgS/61ZqCKpm/cYHyWDlc8cN/7UD4xGKx1IrSSIaGX5F/ymgfh5m8Vujg l+3f9hpvKA0dw== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:49 +0100 Subject: [PATCH v2 29/40] mm: drop some redundant checks around hugetlb VMAs Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-29-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2730; i=ljs@kernel.org; h=from:subject:message-id; bh=2GAQjO/s/Bk0fyt5AOQ4Ez3Tt7coS55V2FI+CqksX6E=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG8y9Upv+BalpReh8y7L8R+HfP1fb9OdlmuZmH81p en+ufO0o5SFQYyLQVZMkeX5F/H9QSJh8zov+LvBzGFlAhnCwMUpABNZWcTI8ML48+2lyXeydx9e 6+7IyxZnVHwvST++88aidzfFfmhPX8nI0CY7MX4J7wnG2+f2mn++Ze5/7dKk/PiaX+uq/rOVF1h OYgQA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Adjust code which inadvertently perform redundant checks on hugetlb VMAs and clean them up: * hugetlb VMAs have VMA_DONTEXPAND_BIT set so a VMA_SPECIAL_FLAGS check suffices. (migrate_vma_setup() regains an explicit hugetlb test later in the series, once VMA_SPECIAL_FLAGS is removed.) * hugetlb VMAs unconditionally set vma->vm_ops, so they are never anonymous. * hugetlb VMAs do not set VMA_PFNMAP_BIT so checking for this is redundant. While we're here also drop a VM_BUG_ON() which the simplified check above makes unreachable, and use the new VMA flag API. No functional change intended. Acked-by: Marc Zyngier Signed-off-by: Lorenzo Stoakes (ARM) --- arch/arm64/kvm/mmu.c | 4 +--- drivers/gpu/drm/drm_gpusvm.c | 3 +-- mm/migrate_device.c | 4 ++-- 3 files changed, 4 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index a7968f8d24bf..3c1240ffc38d 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1463,14 +1463,12 @@ static int get_vma_page_shift(struct vm_area_struct= *vma, unsigned long hva) { unsigned long pa; =20 - if (vma_is_hugetlb(vma) && !(vma->vm_flags & VM_PFNMAP)) + if (vma_is_hugetlb(vma)) return huge_page_shift(hstate_vma(vma)); =20 if (!(vma->vm_flags & VM_PFNMAP)) return PAGE_SHIFT; =20 - VM_BUG_ON(vma_is_hugetlb(vma)); - pa =3D (vma->vm_pgoff << PAGE_SHIFT) + (hva - vma->vm_start); =20 #ifndef __PAGETABLE_PMD_FOLDED diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c index a1d4989b0b61..fab34fea99c2 100644 --- a/drivers/gpu/drm/drm_gpusvm.c +++ b/drivers/gpu/drm/drm_gpusvm.c @@ -1141,8 +1141,7 @@ drm_gpusvm_range_find_or_insert(struct drm_gpusvm *gp= usvm, * limitations. If/when migrate_vma_* add more support, this logic will * have to change. */ - migrate_devmem =3D ctx->devmem_possible && - vma_is_anonymous(vas) && !vma_is_hugetlb(vas); + migrate_devmem =3D ctx->devmem_possible && vma_is_anonymous(vas); =20 chunk_size =3D drm_gpusvm_range_chunk_size(gpusvm, notifier, vas, fault_addr, gpuva_start, diff --git a/mm/migrate_device.c b/mm/migrate_device.c index c38cbaaef5a4..b9c453c28795 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -743,8 +743,8 @@ int migrate_vma_setup(struct migrate_vma *args) =20 args->start &=3D PAGE_MASK; args->end &=3D PAGE_MASK; - if (!args->vma || vma_is_hugetlb(args->vma) || - (args->vma->vm_flags & VM_SPECIAL) || vma_is_dax(args->vma)) + if (!args->vma || vma_test_any_mask(args->vma, VMA_SPECIAL_FLAGS) || + vma_is_dax(args->vma)) return -EINVAL; if (nr_pages <=3D 0) return -EINVAL; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 F00174A015B; Mon, 14 Sep 2026 15:13:16 +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=1789398798; cv=none; b=YYJUpiGuEEsdfH2IaGptXbE3xOivz9k8h7/pVBJEV2qr303yhQs1uroDq2fxG34I8NPoYrklaHI9/RFYQwOs8StjzZIKocTGe3sllkWt/dy6+jcBl5TZpM3LM/G95ak+Xa1+Ibdvn4oM4gjMu6wMzWF0m6nXypugvd33PPAezbE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398798; c=relaxed/simple; bh=sRYt0UudvtAxeO0KRMBxTGrVTVnQqrjgMi1gjOlaTgw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=LslRA/3EUZgL/r6oCZIFkuGlCzeU3cQvEyfNpyTLucjfDlDLL5N+ScCIQvp33buG2qwMdS5pXz8rItkRN+Je/VQzi93G605pOQjcU0mofF0Pm35OmO9sNyjMgWoxe4ntyMAH0yTlYNmKw+1LViOzMQi3wtQ4A07gVsR/Kfb1KnI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=giTEJWAG; 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="giTEJWAG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B64571F00898; Mon, 14 Sep 2026 15:12:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398796; bh=rpQUY90Yz1fvoWb/n9qt0DfA+MP9PvsomcDJoStRF6M=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=giTEJWAGg3uyn+vJXPvP/uZMz1rn5iOfy0BoKhWd1V/HgLWZdIpfJnUiGeOAXc7CM hRNwcWix2D2axraH/QCbSYKgQBsXB5LrInzHzxqty14LGA38Wy7ax9Hi0WBR2mP44i UzO7s9Ak4hpXxx65cYiC4x5v/lhuAp5/uyh/QpM8DIpxH0qilikUP96EhXWQPvSWvN b1TqqVNHgP1iQd+BNAED4Z3pTgF8pSIZ+gE2QMCjiGlr9OK0Te994emHbtaA0yZ4sZ RKvs0iZwx5cSniV3huEhvRpznV3cZ9pp61bBjhmUbmPXpFGu9mPxhZFqx6LYjD3iuj IYHrlBmNClq2A== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:50 +0100 Subject: [PATCH v2 30/40] mm/madvise: update is_valid_guard_vma() to use vma_can_merge() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-30-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=1939; i=ljs@kernel.org; h=from:subject:message-id; bh=sRYt0UudvtAxeO0KRMBxTGrVTVnQqrjgMi1gjOlaTgw=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG9iyfS4/OKN2+Y5a/9JN/z+xOnZNuXn8o5sWz62v 48Vri7g6ChlYRDjYpAVU2R5/kV8f5BI2LzOC/5uMHNYmUCGMHBxCsBEdpcwMkx9Nyd8mkXf1UrG JbuPtehP2fR3veLV6j0PSk7wOxfeStBk+Ke6pGiFuMRn85lvb/YEBAt47DmzeSLPZmvexPwuT1O RcjYA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 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. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/madvise.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 467601a8525b..0922d5f07a12 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1221,19 +1221,25 @@ static long madvise_remove(struct madvise_behavior = *madv_behavior) return error; } =20 -static bool is_valid_guard_vma(struct vm_area_struct *vma, bool allow_lock= ed) +static bool is_valid_guard_vma(const struct vm_area_struct *vma, + bool allow_locked) { - vm_flags_t disallowed =3D 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 |=3D 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; =20 - return !(vma->vm_flags & disallowed); + return true; } =20 static bool is_guard_pte_marker(pte_t ptent) --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 C0A5B36C0C8; Mon, 14 Sep 2026 15:13:44 +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=1789398827; cv=none; b=ewd/d/unzITk+7PegSO+NgSkDV4EvdmaQAKDxFUYKqF62yAyG0DbTbXRxn612Bix0Y5NDll9hKkr49/ZcGWerC7IiYpvCHxZ3Ang80cnWrURI9zxo8aOYO7k32s/MyXdnXmq6ZN9RIo7N+q1t1LWm5+PrTN5ims/XwUmxYR8xdI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398827; c=relaxed/simple; bh=g+DP477oZGptEtdcgQ46pNPCZKGp7Qm9RMjCOcTExak=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=C6wyPK8vRcdsYsj5JoAlBRDLSMuq9PnHa8kl6m7m0/GAYwAIyMXZuZalgrh++noxeiV0wxTultwKNxryQG8BjxSBV5x3OIcnKnZOutnj+O/F/sXZPlaCMwTZB5jluPwWPav+z1tGU111oa6zNdX6DfnuUTOZE65Uevt3nqqKgXM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OCxKcU1+; 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="OCxKcU1+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BA611F000FF; Mon, 14 Sep 2026 15:13:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398824; bh=lLYk3o3B0/wt5kKG7m+ibDGyo2yi3t47XmKybZiJ1Rs=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=OCxKcU1+iK7/VpwiCjQsfNTyLHXprYAfmjBTJYjRXOqSDbjChS9a8UNWWai1dvAvc LIfatKmb7N324OjNPygUEBox7bMevCjzeSSuDsi2zo2gQV1Ch4rMdfyF2YwhWGS3lr mpzUli8fzWIJhtFi5+YHpAYOWyN/jkakLNHYxhkIn0hGO8FueA/PbeqVLU3sNzh8kG tasN7UGKUrwoUktzW8P94NZIU1a77PHfaA1s+GCbww/WCsxnkXLSH7cR3ehb48gVPf Fubs33Mx1iVz8PhSbmXgoSeIcWefLZFQUci+t3J8RTXMiJP+VHzSPoJTGPDnXZiwd8 +nOVg4gC8GBtA== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:51 +0100 Subject: [PATCH v2 31/40] mm/vma: introduce vma[_flags]_is_persistent() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-31-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=3843; i=ljs@kernel.org; h=from:subject:message-id; bh=g+DP477oZGptEtdcgQ46pNPCZKGp7Qm9RMjCOcTExak=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG/2/cAr06Se1Z6oeyNo1uIpW3/LZP3oLp+5ibet/ 1rNzn+fO0pZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjCRwm6G/4mn72lnsnPnfDI1 f+xlZ1mTPzf8Q97GdUwHP9dFzno7I4Phnx1H56oJh/InyuxULtwcU5l59dZs6bsXT/Uu3mC+3KF vBicA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Introduce vma[_flags]_is_persistent() for the purposes of identifying mappings that are persistent in the sense that bytes to the mapping stay there, and bytes read from the mapping are the same unless changed by actions taken by userland. Kernel-owned mappings do not fall into this category, as their owner may change the contents without the user having initiated it, and nor of course does memory-mapped I/O. We exclude fixed mappings as these are singled out as being unmergeable and so cannot be guaranteed to persist user data. hugetlb mappings are fixed mappings, but their contents are entirely the user's, so they are explicitly carved out as persistent, as the MADV_DODUMP check already does. It excludes droppable mappings, which by their nature are ephemeral. Use this functionality to update the madvise MADV_DODUMP check to test for persistence rather than open-coding this. This replaces the VM_SPECIAL check which means it no longer checks for VMA_IO_BIT, however this is safe as we have established the invariant that only kernel-owned mappings may set VMA_IO_BIT, so we implicitly include these. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ mm/madvise.c | 4 ++-- 2 files changed, 46 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 154fc25c9efa..0579e6afb19f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1741,6 +1741,50 @@ static inline bool vma_can_merge(const struct vm_are= a_struct *vma) return vma_flags_can_merge(&vma->flags); } =20 +/** + * vma_flags_is_persistent() - Do the specified VMA flags imply that the V= MA + * contains persistent data? + * @flags: The VMA flags to test. + * + * Persistent in the sense that - if you write bytes to the mapping - do t= hey + * stay written? + * + * If the kernel or a device could write to the memory independently of + * userland, or the kernel could arbitrarily discard it, then it is not + * persistent. + * + * Returns: true if the flags imply this VMA is persistent, otherwise fals= e. + */ +static inline bool vma_flags_is_persistent(const vma_flags_t *flags) +{ + /* hugetlb is a fixed mapping, but its contents are the user's own. */ + if (vma_flags_is_hugetlb(flags)) + return true; + /* + * MMIO mappings may not store what is written and may be changed by the + * device. Kernel-owned and fixed mappings may be changed by their owner + * without the user having initiated it. + */ + if (vma_flags_is_kernel_owned(flags) || + vma_flags_is_fixed_mapping(flags)) + return false; + /* Droppable memory is discardable by definition. */ + return !vma_flags_test_single_mask(flags, VMA_DROPPABLE); +} + +/** + * vma_is_persistent() - Does the VMA contain persistent data? + * @vma: The VMA to test. + * + * See vma_flags_is_persistent() for details. + * + * Returns: true if the VMA is persistent, otherwise false. + */ +static inline bool vma_is_persistent(const struct vm_area_struct *vma) +{ + return vma_flags_is_persistent(&vma->flags); +} + /** * vma_kernel_pagesize - Default page size granularity for this VMA. * @vma: The user mapping. diff --git a/mm/madvise.c b/mm/madvise.c index 0922d5f07a12..e15973292f94 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1584,8 +1584,8 @@ static int madvise_vma_behavior(struct madvise_behavi= or *madv_behavior) new_flags |=3D VM_DONTDUMP; break; case MADV_DODUMP: - if ((!vma_is_hugetlb(vma) && (new_flags & VM_SPECIAL)) || - (new_flags & VM_DROPPABLE)) + /* Non-persistent memory cannot be dumped. */ + if (!vma_is_persistent(vma)) return -EINVAL; new_flags &=3D ~VM_DONTDUMP; break; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 21DBC4A64EC; Mon, 14 Sep 2026 15:14:12 +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=1789398853; cv=none; b=XFRz8xUgIDFKishOZBJkr6EOkE8CbOolcqyxQUEISr1FFV5d7itI6cSREQviU32UL4bg3dcZTvNydGAOsCJaNa5eRgtKaYsgHms3iCloyEdnPQ26BzoPhTAsdOaeULBalwnH3Zz9KlYudInj9ZLuAsCAlq1tzdtU8vY5Qntsnd8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398853; c=relaxed/simple; bh=RaKyg3GqRiVqHvw/UDaaHvGcpLhQwigi+RNlsL2zffs=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=mYvylYC1HtmDo5zer89i7rA+XNYmOEaNuF6m+sTdjv8PU2uuNkUG0HxX0p4WwsKMRRv11CEH1Q41T8grsLyoqC59rUC8a1hjvRDyd8EGT3jqKZAeaHMrvngpu6KxFyA4veqrqIyIsGBl+zhAWAW+gs2xSphYphmFUj+2W+aQ4ZE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mQuGz7/t; 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="mQuGz7/t" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C36861F00893; Mon, 14 Sep 2026 15:13:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398851; bh=9WoUWUiccCZ5pmncdG/fVn1uDF622HEjGzqeAT5aHc8=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=mQuGz7/txzYesAJMtBCbn7ZfzTB/KlNr4TPqovuNgSOoVCydbhk+jy3YSFL1zSmj7 ZngEXa8qEB1QbOt+DaIqYYLRuiCYf94eeH2j/KUez4FgSi35O5IJ7/3VirViisn0l7 45yaoBch2L7x0ZnN2BWOFTWs/9m7lJmF7hB5vrV7UHzq2uMwUDuRBM/jRLb2L2GP99 R7er+Xj9cWvH8j+SJqxYM/LxLtIRfdl/2/HuvWNx/tMnUZW/H5z6mP0BpNbe/OoMZG uobtsLE/kEt9BejhdkmRL2yFhy/FKtBfHsR9mVL4p7wohnh1s4Vt90A3QJent8U+sy alzgjeWOejIqA== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:52 +0100 Subject: [PATCH v2 32/40] mm/uffd: use predicates for userfaultfd checks Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-32-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2289; i=ljs@kernel.org; h=from:subject:message-id; bh=RaKyg3GqRiVqHvw/UDaaHvGcpLhQwigi+RNlsL2zffs=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG+20diWeckzqyprhU5s+VX2eL/c5gBf4dWSYUdaM 0/unx/WUcrCIMbFICumyPL8i/j+IJGweZ0X/N1g5rAygQxh4OIUgIlkaTIyzGt0Mi2q2NqRoZBy yFV/Y/5strlZB2c3V654Y1djMDF3H8P/+G3WItOMT93bYSEkVDGl1X151a4eiTh7i8MfdpwVOOT MCwA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 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. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/userfaultfd.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 949017e60608..ddf0a4a3d399 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -1754,10 +1754,18 @@ static inline bool move_splits_huge_pmd(unsigned lo= ng dst_addr, } #endif =20 -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; } =20 static int validate_move_areas(struct userfaultfd_ctx *ctx, @@ -2146,10 +2154,11 @@ static bool vma_can_userfault(struct vm_area_struct= *vma, vm_flags_t vm_flags, { const struct vm_uffd_ops *ops =3D vma_uffd_ops(vma); =20 - 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; =20 vm_flags &=3D __VM_UFFD_FLAGS; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 3592A4A8A3A; Mon, 14 Sep 2026 15:14:39 +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=1789398882; cv=none; b=SNqGIPveXdWHd5SfEFJRtwKZgS3H9O4LJoZ0z/G1jvIGzEeoD5jMx9KQYyj+uQMIrMpYpEQRHF5CNqN3CteeXNZcDoyOSFC8OqqqWDCkYtt4zWdupF5/B9Qx59SfjignGWaMT9Za0cu41FYvU/1cR6EeIsOb0asdUOfz8UqaTPM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398882; c=relaxed/simple; bh=73C/rtzFa+0ZWXqoblfAsIR57zB38R+k6a/jXJhy+os=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=kSonoIMSLUW9ysgjf3mejCfrAZIrrGYuWwrTFf2K8RPgHIjyYRHT8tSYeW8MKDgb4Cie7cwE2kl37bXXhmRqT4IjWxXBQaSjNKcIEFCfkRN+aqtCaLHEOR9kD86tcF31UVrTr6bMUje8fc646yr+R8ZAoPPh5RW9XlaX8CkZtu4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LmNN6RDd; 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="LmNN6RDd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 561D31F000FF; Mon, 14 Sep 2026 15:14:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398879; bh=Q7igvapfDwrm+6txgQcyn+RMKEShI1bTZhFDIgbQAbI=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=LmNN6RDdl3OcQfn8BQ+xntQhwL6LNv57jORy8fPYj5F3Tw4d+J4Gv/urFCS1HPduv 9ga8gb8IS9Nb/Ri8aU5npchcY54I1jT0dihVMpK7TsTa6iVXCXEE/e90D6Alpyf3oD nUxAaLD6ui73ipxcnnE4PaxYOmYSQ0ckxQNI9wpfq/zaipTE9ex+dQxiHxuaQVI6lQ wWBBDhlhRX6OW9pBVgkPf8NAVf/hz7F7FHcLQ0iSVUrZtrfkvnkgGZoOQbMZcy6iK3 pIkNxaTA0MlSECXaa4UzJfWxeIUc9OSfpLcws1hNxglEKAY0qeQTM7P+e1kk9P91bD H7071teIJBfYQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:53 +0100 Subject: [PATCH v2 33/40] mm/madvise: use predicates for madvise(..., MADV_DOFORK) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-33-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=1318; i=ljs@kernel.org; h=from:subject:message-id; bh=73C/rtzFa+0ZWXqoblfAsIR57zB38R+k6a/jXJhy+os=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG8+vjHgcrw8f3fW07Wfj1QxRP/ycbZSLhQpuLxxe +huBUH/jlIWBjEuBlkxRZbnX8T3B4mEzeu84O8GM4eVCWQIAxenAEykKJ7hf9jpecrcvEZFSdM3 mHbmvdg35YBXV/5s9dTuXWfer/38XpyRYYKUS+2ulWxlWmuuG6c3V2k2Lry76n6ekfzEDq/vFVn ZrAA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Make it clear what we're blocking in MADV_DOFORK. Previously we simply disallowed VM_SPECIAL i.e. kernel-owned mappings, fixed mappings and VMA_IO_BIT. Now the invariant is established that only kernel-owned mappings can set VMA_IO_BIT, the VMA_IO_BIT check is redundant. The rest is equivalent to testing for a kernel-owned or fixed mapping, i.e. exactly the same check as whether the VMA is permitted to be merged. This was established by commit 0b2758f48f22 ("Require (reasonably) normal mappings for MADV_DOFORK") containing my hands-down favourite call out of all time. Express the same thing differently - if we wouldn't be allowed to merge it, then we aren't allowed to manipulate CoW behaviour on fork. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/madvise.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/madvise.c b/mm/madvise.c index e15973292f94..1af82b044d23 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1565,7 +1565,7 @@ static int madvise_vma_behavior(struct madvise_behavi= or *madv_behavior) new_flags |=3D VM_DONTCOPY; break; case MADV_DOFORK: - if (new_flags & VM_SPECIAL) + if (!vma_can_merge(vma)) return -EINVAL; new_flags &=3D ~VM_DONTCOPY; break; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 AC7664AC161; Mon, 14 Sep 2026 15:15:08 +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=1789398913; cv=none; b=LNwIGOJSZuYnDGHUOFKStugbw2T33+i6LVtbDMCOtfx5oixg070TiIc+a7wxMo9dhQ+ODW6fuk/HBDPEXcDwvf8S6mbj4NLxyUnwL9WrgPoiq85CynsLWAAA6jl3uLUq9XrACkcqdsN9mmcR5DYodjLqym38sA3prqdd8sjY5xY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398913; c=relaxed/simple; bh=eDLmjh2bzHIv4YAPniXBvBcmDHaqL2K0F9inIsPpqyE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=DX7XVQDs3YGlwLTjBA7I7kkGPNImlcfbe3Wo1v6BUu5eFaaA/NolIq1z8RczVCpYqYweVB+HsCFmlZw50+dJptG41S77ZUtnxngShczYlU2HjjVqFOXAuZXKiJ629GPSSMqboukh+ee3YAUBfcE6hCtnM616axae3+QSK81R4c4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O4g8Eomu; 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="O4g8Eomu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D25111F00899; Mon, 14 Sep 2026 15:14:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398907; bh=1/40s6lyT9bZpyR+Yy0EbDmmnq6isDZhtDSiJykjXkI=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=O4g8EomuSoGBr7JylEOBMDOs3EdIDMAHiNHZiNGz+WkNkHzqvkLnkveyns92XmSaK wAzE3bORHhTGKcAQe5Hf8hb/+VQbrptzz+7CpdpSbhSF6Ak9fW+WiMgHW7pdBriEZb x1qYzxdun1eTBlP+f0tcdbxD/mcC8XDF9QvwLAItTu+ZCl8rGQ1ivKpjUoQLjAVuve TQkUIu+X2Hd82kd+orGw8xK7SiE5bY3VPKvliUth4R5/IbejZhi62XqkkKwt+1y25p 0sHJHkcCeG+Ri3Wx73Wf7lYpasYmVxZfDSV/Zm9zNWhuwtzQWZm1Wt5g7T4j79mhUw wlQ58L1roQOOg== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:54 +0100 Subject: [PATCH v2 34/40] mm: eliminate VMA_SPECIAL_FLAGS usage when hugetlb explicitly tested Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-34-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2543; i=ljs@kernel.org; h=from:subject:message-id; bh=eDLmjh2bzHIv4YAPniXBvBcmDHaqL2K0F9inIsPpqyE=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG822Cv1Qqjn/738q/w2imubyv2Yroc8Xc7CMn2BK M+FzX1/O0pZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjCRmd8YGY4+iF7kaBlja2M/ has0996Dzf52ZxQyGKu113QtjUpWUWZkaM0/pbGovvL7i22q23s3Cwn6htf/l/mc5GKntH3nROa L3AA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 It is now an invariant that VMA_IO_BIT is not set except by kernel-owned mappings, so each existing VMA_SPECIAL_FLAGS test need only test for VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT and VMA_MIXEDMAP_BIT. This is precisely a test for a kernel-owned or fixed mapping. Update a number of callsites which already explicitly handle hugetlb mappings. vma_supports_mlock() and ksm_compatible() also explicitly bail on droppable mappings - detecting kernel-owned, fixed or droppable mappings is handled by vma_is_persistent(), so in these cases use this predicate. should_skip_vma() tests for locked, kernel-owned or fixed memory (having already excluded hugetlb mappings) so simply test for those there. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/internal.h | 4 +--- mm/ksm.c | 4 +--- mm/vmscan.c | 3 ++- 3 files changed, 4 insertions(+), 7 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index 1b6153013061..83a4ba52aaeb 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1111,9 +1111,7 @@ static inline struct file *maybe_unlock_mmap_for_io(s= truct vm_fault *vmf, =20 static inline bool vma_supports_mlock(const struct vm_area_struct *vma) { - if (vma_test_any_mask(vma, VMA_SPECIAL_FLAGS)) - return false; - if (vma_test_single_mask(vma, VMA_DROPPABLE)) + if (!vma_is_persistent(vma)) return false; if (vma_is_dax(vma) || vma_is_hugetlb(vma)) return false; diff --git a/mm/ksm.c b/mm/ksm.c index 624f37975e12..f80372bfd4b2 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -747,9 +747,7 @@ static bool ksm_compatible(const struct file *file, vma= _flags_t vma_flags) if (vma_flags_test_any(&vma_flags, VMA_SHARED_BIT, VMA_MAYSHARE_BIT, VMA_HUGETLB_BIT)) return false; - if (vma_flags_test_single_mask(&vma_flags, VMA_DROPPABLE)) - return false; - if (vma_flags_test_any_mask(&vma_flags, VMA_SPECIAL_FLAGS)) + if (!vma_flags_is_persistent(&vma_flags)) return false; if (file_is_dax(file)) return false; diff --git a/mm/vmscan.c b/mm/vmscan.c index 12ed3388ee41..09ff20c3df5b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3477,7 +3477,8 @@ static int should_skip_vma(unsigned long start, unsig= ned long end, struct mm_wal if (!vma_has_recency(vma)) return true; =20 - if (vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) + if (vma_test(vma, VMA_LOCKED_BIT) || vma_is_kernel_owned(vma) || + vma_is_fixed_mapping(vma)) return true; =20 if (vma =3D=3D get_gate_vma(vma->vm_mm)) --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 013944A2A69; Mon, 14 Sep 2026 15:15:34 +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=1789398936; cv=none; b=rtMOK83H1OtHo9O/7mB+wo/LCBnrzG1SfHsy1B9Bf7X/JjFoZ8egQnfHFFGeNhH474bxSWb2qhqMkymcS6/JH8rWUlgwZW/zdCP7vF4NGHY34N/mcnYPuD/Qoyqn/MRlBHVnDvkN+vDd4XyyCmXnncCsHfwOSeqRWEMWaRyDv7Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398936; c=relaxed/simple; bh=DL5e220u7y3LwD4Eiaa74zWyGi+IuXsLh7IOYBtbckQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Rs7XmQhmlY2YPAVWlKx9RfdoezIr5Gkyr15nVguzrX3ogiAWl/zSo45+92KXu4Vugmq6qipA9DwHy11uia4cXzVn56onwU+iZ+hINMIvmW+uOm83IXXriWs4yC9a3hJgmewGEhgWQygwBwYwUcHBhaOSu2oBX0G0zXck6ryEkKA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mOvtEAP9; 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="mOvtEAP9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 956261F0089A; Mon, 14 Sep 2026 15:15:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398934; bh=1QRQ9WYzmW2nABpmD05iYHWtoRPkYuNGcAfZon3VB64=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=mOvtEAP9mPvYRv+kMi8JpK6J5piWtC7mopHhpUWS55/I8zHQGuypMZqh4urJyF2Qr apEaaccXcJtnRx0Kp8BqmyvAtzBIGRCrRJWItSQZMB/+f2SCriernKJuwlajnxGHUn Mrul+75M15zjqZey5g3rQVaXpw/zP77Jf3vd+hK46vUU2VwpeiAuIYKAwIXJBjYDsb QJTlEeLAJQm8i77cAF846R7Wx0K8/D1fkvBD3fFPOM2OqSmiO3ZqqztAFS4e7l8/bk DRRKUipCswsOWUEjKa1BGOYBBa3zGI5nSkoUwvFiHCc+NrI4Xsp1pop5TdsKyxOKfe GJ/0vsjlv+u9g== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:55 +0100 Subject: [PATCH v2 35/40] mm: eliminate VMA_SPECIAL_FLAGS check in lru_gen_look_around() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-35-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=1176; i=ljs@kernel.org; h=from:subject:message-id; bh=DL5e220u7y3LwD4Eiaa74zWyGi+IuXsLh7IOYBtbckQ=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG9+1Zi3qG4Fa8Bxt/NbAvdeOcAXmx3HJPSFZ2ru6 7NH2PzOdpSyMIhxMciKKbI8/yK+P0gkbF7nBX83mDmsTCBDGLg4BWAiC7cxMixhPOYQdkK+Ra39 tnjr05t+OkePatb8fXX86LfV5aXFLw0ZGRZnh7ROPxGrx58wUYdR+2HSZ76uLc2rauZ9SRY24tj wgQUA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 A kernel-owned or fixed mapping is one which sets VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT or VMA_DONTEXPAND_BIT, which is precisely what VMA_SPECIAL_FLAGS tests for other than VMA_IO_BIT, which is safe to drop as only kernel-owned mappings may set it. Using these predicates rather than VMA_SPECIAL_FLAGS makes the check self-documenting and helps eliminate the confusion around 'special' flags. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/vmscan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 09ff20c3df5b..001f8b760266 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4418,8 +4418,8 @@ bool lru_gen_look_around(struct page_vma_mapped_walk = *pvmw, unsigned int nr) if (spin_is_contended(pvmw->ptl)) return true; =20 - /* exclude special VMAs containing anon pages from COW */ - if (vma->vm_flags & VM_SPECIAL) + /* exclude kernel-owned and fixed VMAs containing anon pages from COW */ + if (vma_is_kernel_owned(vma) || vma_is_fixed_mapping(vma)) return true; =20 /* avoid taking the LRU lock under the PTL when possible */ --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 9091E6FC5; Mon, 14 Sep 2026 15:16:02 +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=1789398964; cv=none; b=AhDon1g/LXZplyXrvqryVriz64hnp5RxfkyaQaiKglfPR2pJqwcf1rI899Q/8cUIowuJhJiHaHB45M0Ovg/C2bwHPCkJQvuAQ3bJjd59KCsXfqzJA50TfaXJ6Mau0QcLZZSP0xHXPghk7iYX2UtYGdAId871Ii6aQpP8gCjGHvc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398964; c=relaxed/simple; bh=12r+57hlfcUqhp52wOQ04zakYjCIf/s1O/YwMYeI4F0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=sNEXLuhwNK9N2kc1G3YcbtFmZCqdDaMjBvJGuAOKCd/asRZOKjKFWexWwjdhz6fT1xteWB9mM/5Xk8fmOoHsRrSMVOUOn2YKy2sbvtwdV1plmK1dkAu68IX9d2elgrEAiCHw5PJR9Rkm2Q0ZExmRMuSUoRtNVY0y/jIiN14L5XA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MxdrCpLO; 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="MxdrCpLO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D6321F000FF; Mon, 14 Sep 2026 15:15:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398962; bh=FbEvWuDC6KaxDOww6JLm5X1oq7s2JCzdjzk0eBTVi0U=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=MxdrCpLOC2vOCZcemtaZ6oFnmQ0a8pPB9nN7DsCjDHO9sc0yLP4UpDwQK1Qd76bot i90zW1WlgaXHZYE+aNgAogt/AgbuilxhUbeQIQJqk379nZKlkI9G2ntVYJTNaOHtk5 raRFGevq+sCzIEM4IoiUyZQxm4gpkiTWvUTfaWLf9Hd7gfcDTXzzaFmdGcqkWSagwR 8SFE2RsHHzFCmWDpxYDJYOK0mz6bqQe+bt4SsxlRXb5iAvT+WwozYdJ/oCY5gMr5vW VWXg3xogLHwk2Db6zMqdOZu9xIvo+VLBk1KAGmklN7d4S6MOUrKkrf8+19eA48a7Iq wNhDnwwUNJWMw== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:56 +0100 Subject: [PATCH v2 36/40] mm: avoid use of VMA_SPECIAL_FLAGS in migrate_vma_setup() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-36-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=1631; i=ljs@kernel.org; h=from:subject:message-id; bh=12r+57hlfcUqhp52wOQ04zakYjCIf/s1O/YwMYeI4F0=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG9mmpoQf7zZ3fy3Qrqw7jOm/b1ico4esTundPTu2 1jebravo5SFQYyLQVZMkeX5F/H9QSJh8zov+LvBzGFlAhnCwMUpABP58Z7hf4CmAXd8eStvfkbe hP/b2GrnNPCGvT3x4dCJ9gmGymlrZzL8Zt0e2MmX/mib5xep7V555lc+Nkqb+u87Y56650S45L3 /jAA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Now we have the expressive vma_is_kernel_owned() and vma_is_fixed_mapping() predicates, use them to determine whether to proceed with migration. This drops the VMA_IO_BIT test, which is safe as only kernel-owned mappings may set it. hugetlb mappings remain excluded, as they are fixed mappings. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/migrate_device.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/mm/migrate_device.c b/mm/migrate_device.c index b9c453c28795..b74c0ae42768 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -739,19 +739,21 @@ static void migrate_vma_unmap(struct migrate_vma *mig= rate) */ int migrate_vma_setup(struct migrate_vma *args) { + const struct vm_area_struct *vma =3D args->vma; long nr_pages =3D (args->end - args->start) >> PAGE_SHIFT; =20 args->start &=3D PAGE_MASK; args->end &=3D PAGE_MASK; - if (!args->vma || vma_test_any_mask(args->vma, VMA_SPECIAL_FLAGS) || - vma_is_dax(args->vma)) + if (!vma) + return -EINVAL; + if (vma_is_kernel_owned(vma) || vma_is_fixed_mapping(vma) || + vma_is_dax(vma)) return -EINVAL; if (nr_pages <=3D 0) return -EINVAL; - if (args->start < args->vma->vm_start || - args->start >=3D args->vma->vm_end) + if (args->start < vma->vm_start || args->start >=3D vma->vm_end) return -EINVAL; - if (args->end <=3D args->vma->vm_start || args->end > args->vma->vm_end) + if (args->end <=3D vma->vm_start || args->end > vma->vm_end) return -EINVAL; if (!args->src || !args->dst) return -EINVAL; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 E75F14949E5; Mon, 14 Sep 2026 15:16:30 +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=1789398992; cv=none; b=TZk3QD91oOH8UgWPqGwlfXysLCVfUVFVMcgmEOnDb1YCDkWINBB2ureAfDCe4n3cZ539PazDHabqQ+ufbRz/DgnjSiOcxQ6uenVCLyC0nzeYxSuzBZ/gwf85aZYnzIWbqTaN8As86yvmDj3zfRXzcGV5tvawRFsskP72tn+8OR8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789398992; c=relaxed/simple; bh=lzK+2c/tEosn3RgAl/J0FNyvUX6YrR1d8AVyW8bOJGU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=bwt1IdcUvydrL+zVkNjV5Z8BXe2wgS2fg74romjWtczifRdMh+DLfsuIOSzZcNVPAhKDC/TN4oXz2f2vh0kkq4nSRe9kXUIa+rLXxMJEeZtjwF8Mmzj112hYaQtId/BU6Rf5WyBjjSwfJUAyfIiizOCq+dRuNxaRgbsbGu5trdI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VpSMzAnS; 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="VpSMzAnS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 932411F00893; Mon, 14 Sep 2026 15:16:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789398989; bh=XL6LKrd6M/PBNjkU6hF8z6KNQ8un+D3E9f5GrhJIaKA=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=VpSMzAnS+A0EUvVcscKjUFm7YaTugBaGsQpZqkD7dfIWRrVXvOUf4AZg5eiUIkgYb vNr1ifzun1Cr2XzqBIyUGEJhCva51xAQ/uSRdxXaFIXps05ytE72SCrNMODy3PtBv5 CA6bD3grq8paI2j/M8rV5qTJT2PHki3kbR5ws0Co3vm1sOHIU7aZxJ8Dw27RLLoHsS 4igGaxrRkN5Kmre20YkQB1uTXCp6EeIOc2bi0OwRERk6TRlrmZ5eY2g7o0Y33slxPM k7XUBmGGCptiE2ctMFAtHiaIzfV7jvIPd5XRMFRgs3P0fwHdmKde2x8Geb9KvZgkR1 eT2vUY5lEQ/dQ== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:57 +0100 Subject: [PATCH v2 37/40] mm: eliminate VM_SPECIAL, VMA_SPECIAL_FLAGS Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-37-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2135; i=ljs@kernel.org; h=from:subject:message-id; bh=lzK+2c/tEosn3RgAl/J0FNyvUX6YrR1d8AVyW8bOJGU=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG9Zt9pOavsKvgW8ORm3rs6//269i3P5myfBKT/+L Kqoy+au7ChlYRDjYpAVU2R5/kV8f5BI2LzOC/5uMHNYmUCGMHBxCsBEpr5j+F97cZlqw7eHRulX U/mjZ3F33bsre1BCPMy66nSTTuOTXD9GhmtsRzQO7H4V8+7B7FbvW8EfFq20ns4Q1OA3v0B2+8F nTTwA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Every user of the VM_SPECIAL or VMA_SPECIAL_FLAGS has now been converted to predicates which explicitly express what is actually being checked for rather than the nebulous concept of possessing 'special' VMA flags. In any case 'special' is not so special a term of art in mm - it includes VDSO/VVAR mappings, special in the sense of vm_normal_folio() and probably other cases too. Therefore make things less special by eliminating these now unused flags. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- include/linux/mm.h | 8 -------- tools/testing/vma/include/dup.h | 8 -------- 2 files changed, 16 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0579e6afb19f..5860a3b4dba9 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -576,14 +576,6 @@ enum { #define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC) #define VMA_ACCESS_FLAGS mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, VMA_EXE= C_BIT) =20 -/* - * Special vmas that are non-mergable, non-mlock()able. - */ - -#define VMA_SPECIAL_FLAGS mk_vma_flags(VMA_IO_BIT, VMA_DONTEXPAND_BIT, \ - VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT) -#define VM_SPECIAL vma_flags_to_legacy(VMA_SPECIAL_FLAGS) - /* * Physically remapped pages are special. Tell the * rest of the world about it: diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/du= p.h index de429ed4d60c..dc24f43a9394 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -352,14 +352,6 @@ enum { #define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC) #define VMA_ACCESS_FLAGS mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, VMA_EXE= C_BIT) =20 -/* - * Special vmas that are non-mergable, non-mlock()able. - */ -#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP) - -#define VMA_SPECIAL_FLAGS mk_vma_flags(VMA_IO_BIT, VMA_DONTEXPAND_BIT, \ - VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT) - #define VMA_REMAP_FLAGS mk_vma_flags(VMA_IO_BIT, VMA_PFNMAP_BIT, \ VMA_DONTEXPAND_BIT, VMA_DONTDUMP_BIT) =20 --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 775C83D5C05; Mon, 14 Sep 2026 15:16:57 +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=1789399018; cv=none; b=XIjZlVhYqHX2KZbgnDMNbj2SehfTaXCYIFGjPcoffON9JEKE/eEAeYjTF+jgCq9/R2JsLm6ysESW8JKmQ6d40UycwqN5BzPVexAg3wA+1WcwB7NwebE0SVDVzv7zZOLQ34x1dMBM54R5gP01FRS9GgN3a47yX2+wh7WB4J/1g8w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789399018; c=relaxed/simple; bh=RCEYQjEW6MHyrFoJLHJtSFluFNRdmgFFgjkTdNXkXXM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Kx0g3gddPKS5u75GSNUnZg/1K6DvqYjNraKiW8j+9OooLZbyWEMh/9VChCdWlyM9rSPSrHceByzpIl7rNhWfboW2V9gEMzbEecCNhxoACdHSZwofOHUMsIUePvBbULUW+gIeXkVKMlPj61ChQw7N0iNfv7uK8H1T/QykHJUGPz8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MwuPzG5j; 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="MwuPzG5j" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1BF121F00899; Mon, 14 Sep 2026 15:16:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789399017; bh=XwIdZujBqtKUK3euRg5palCjbTo4zKXqAqucXZZYP/8=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=MwuPzG5jc3XwBALazXoyoSf1F6W4Vk7TesRzHZph5bz4NWE+Qhr0xkYShhSOby6xW rRsLSYW3lpaGbKz0UXKHDcy1hFN5oGFQXmC+oSCrSL+pIeqFLtxgAjuvobkHPVYNpC bkw7r5YyO1+m3N/f/mOUQMW6E0zhuAO1Muy5SnYYjo41hU7HOLSyZaprwPDum0aDW+ wY3qEN//rE/RHoA1UXWcDfe8rjaygMowoJ61xJUWjNPQl+8BmChkoCDSstjxCMY0fm L/aqiJBKN2tyqNX8Yb42btZmcizmbyVEnyAAzIsBJ/Qsc7aM3cqFZK65jbBu1VCD+4 9Lp4vmuSs/C7A== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:58 +0100 Subject: [PATCH v2 38/40] fuse: dax: do not set VM_MIXEDMAP Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-38-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> To: Andrew Morton , "Liam R. 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The fuse DAX implementation, added later, copied the old pattern and still sets it. Fuse DAX maps pages the same way fsdax does, via dax_iomap_fault() and ultimately vmf_insert_page_mkwrite() and vmf_insert_folio_pmd(), which insert ordinary refcounted pages and so do not require VM_MIXEDMAP. Setting it only serves to mark the mapping as kernel-owned, making fuse DAX the sole DAX implementation whose mappings are unmergeable, cannot be mlock()'d, eagerly copy page tables on fork and reject MADV_DOFORK and MADV_DODUMP. It also requires vma_is_special_huge() in mm/huge_memory.c to carve DAX out of its kernel-owned check explicitly. There is no reason for fuse DAX to keep on using this flag so drop it. Signed-off-by: Lorenzo Stoakes (ARM) --- fs/fuse/dax.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c index 85cdf0199bc0..a5994f1c637d 100644 --- a/fs/fuse/dax.c +++ b/fs/fuse/dax.c @@ -826,7 +826,7 @@ int fuse_dax_mmap(struct file *file, struct vm_area_str= uct *vma) { file_accessed(file); vma->vm_ops =3D &fuse_dax_vm_ops; - vm_flags_set(vma, VM_MIXEDMAP | VM_HUGEPAGE); + vma_set_flags(vma, VMA_HUGEPAGE_BIT); return 0; } =20 --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 3B33824A06D; Mon, 14 Sep 2026 15:17:24 +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=1789399046; cv=none; b=m93qTQiyJpHmnZNCmp9DR0qBUtCzeeH0qj4MhpyhBqhWJWueofz8Vq6Ia3h42wjKg4K0mP3uCTBWjtwBAyv2ETfMc2agy2VoXMuQ70J2a2Tw6xE6N/gBYr7aUgk3GZIGM9kiu4X4ia4pdmOtMZJYeygpcCZGB+N0F9BjqCmQeII= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789399046; c=relaxed/simple; bh=2A3Cmsn/41H3VCQe0yUXH8gcl1gq+lw+YTsrD11Z3Vo=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=My069i8uzUyz7muSUk489WXrkXA+mzpdEsS32Gq1iVlPg9xMWuU71MOCH7vPsL/EdFROfwIFTWQHg8IopC/3t5Ruq3CRiZLbGRCw8j5oTkOJRANDvcxI4uIL7CdMawCbTzshgvwQqPL3U+4jKPxRtS8rlE5Lry3fCNGoBVqftt8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SIR9Irdu; 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="SIR9Irdu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95F5E1F000FF; Mon, 14 Sep 2026 15:16:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789399044; bh=6Dab/JGj5h11GJwmfZC2qp9KBu5kIrwqs5kjA45qPyk=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=SIR9Irdu2tH++m8RUJNAXIfX+y8cmzgqfzuBuGYIWQ0TzWyN+PpkRuaqE0hD09dhF 2QNm1/6o41Yn0gT/+OJ/G0G10aIqVWyVhxWFxnESR91OAgPBfJSp6X3jQ7AhyfvZw2 aANJyVHI+fLtTSE+zbrvEsmtwtt2vWhQ8mQF7qfVVojm9/PnPA51LirOmYqlA/LXw9 gsivzmLLbdBw8fcXEqLaipbQn0NewPXP22oNYV3bA5Uu13IEplEK6undFCh/jMoQEm UPPgZEhMW3qJ5F+UxegK48iw8tKvfiQ7NyqbyOAVu4dinN9eAsavTj74KxsWAMGvAD Frh2zf0qRwyxw== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:57:59 +0100 Subject: [PATCH v2 39/40] mm/huge_memory: remove vma_is_special_huge() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-39-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=2897; i=ljs@kernel.org; h=from:subject:message-id; bh=2A3Cmsn/41H3VCQe0yUXH8gcl1gq+lw+YTsrD11Z3Vo=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG8pqA6t57l77nT667708LSrs/7p7JtqH1V+ftP+x 9u6P0362FHKwiDGxSArpsjy/Iv4/iCRsHmdF/zdYOawMoEMYeDiFICJxLIyMjzLiwnO2JiibquU tXX2vHL94uNckZPv+09nSznze+XCE/MYGc7uO6d5U6LIwjDY0e3SXsmNr7OSo/jCDM8FxlzeoHn Pix8A X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 vma_is_special_huge() tests whether either the VMA_PFNMAP_BIT or VMA_MIXEDMAP_BIT is set (i.e. whether the VMA is a kernel-owned mapping), but with a DAX carve-out. DAX however no longer sets VMA_MIXEDMAP_BIT, so this carve-out is no longer required. Therefore test for vma_is_kernel_owned() instead and also drop the VMA_IO_BIT check, as it is now redundant since it is enforced that only kernel-owned mappings can set this flag. This also eliminates another overloaded use of 'special' within mm. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/huge_memory.c | 18 ++++-------------- 1 file changed, 4 insertions(+), 14 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index c3c98ea672c3..3cb8e2d4d65c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -110,14 +110,6 @@ static inline bool file_thp_enabled(const struct vm_ar= ea_struct *vma) return S_ISREG(inode->i_mode); } =20 -/* If returns true, we are unable to access the VMA's folios. */ -static bool vma_is_special_huge(const struct vm_area_struct *vma) -{ - if (vma_is_dax(vma)) - return false; - return vma_test_any(vma, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT); -} - static bool vma_file_bypass_thp_tuneables(const struct vm_area_struct *vma, enum tva_type type) { @@ -192,7 +184,7 @@ unsigned long __thp_vma_allowable_orders(struct vm_area= _struct *vma, /* Check the intersection of requested and supported orders. */ if (vma_is_anonymous(vma)) supported_orders =3D THP_ORDERS_ALL_ANON; - else if (vma_is_dax(vma) || vma_is_special_huge(vma)) + else if (vma_is_dax(vma) || vma_is_kernel_owned(vma)) supported_orders =3D THP_ORDERS_ALL_SPECIAL_DAX; else supported_orders =3D THP_ORDERS_ALL_FILE_DEFAULT; @@ -3066,7 +3058,7 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_ar= ea_struct *vma, orig_pud =3D pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm); arch_check_zapped_pud(vma, orig_pud); tlb_remove_pud_tlb_entry(tlb, pud, addr); - if (vma_is_special_huge(vma)) { + if (vma_is_kernel_owned(vma)) { spin_unlock(ptl); /* No zero page support yet */ } else { @@ -3222,7 +3214,7 @@ static void __split_huge_pmd_locked(struct vm_area_st= ruct *vma, pmd_t *pmd, */ if (arch_needs_pgtable_deposit()) zap_deposited_table(mm, pmd); - if (vma_is_special_huge(vma)) + if (vma_is_kernel_owned(vma)) return; if (unlikely(pmd_is_migration_entry(old_pmd))) { const softleaf_t old_entry =3D softleaf_from_pmd(old_pmd); @@ -4765,9 +4757,7 @@ static inline bool vma_not_suitable_for_thp_split(str= uct vm_area_struct *vma) { if (vma_is_dax(vma)) return true; - if (vma_is_special_huge(vma)) - return true; - if (vma_test(vma, VMA_IO_BIT)) + if (vma_is_kernel_owned(vma)) return true; if (vma_is_hugetlb(vma)) return true; --=20 2.55.0 From nobody Fri Sep 25 09:21:17 2026 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 5887248CD48; Mon, 14 Sep 2026 15:17:52 +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=1789399076; cv=none; b=GFRhjG4aHrR/USHygWkRD68B23fCDRfQVhE2ANwFy7joN6o6tafDitwVaf3XzN8m6nLtYzVJheGC/jriXbCOh4f7HnEBN2suhDjhtXZNnGCtCsHHImSSlbXfcBp9caczamC/78DLkDFR5g3UolrQqX43ArX7HbPFyJxTW7TG+o4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789399076; c=relaxed/simple; bh=3AnqccC2jTUlmIOHAi2JESa1NkBfZlWIxg9a+l0jjPI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=KNhoI8Qh/rgfmOs3FfvRb8sPY8gsnnAA2x/FpAUgq6NIMRkLU3GsLtP86Rnjt6Atb6DK+SIdUVOURrrU/EyGjET+vA7u8HBq7Qrwv9/6NMELBbrGiswJC/TnM6dSAYPxkQcFIWDUVKTudyISszkwuz2Ee55UhONcy0VRoj60sLY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SJBEb+Gi; 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="SJBEb+Gi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FFF01F00893; Mon, 14 Sep 2026 15:17:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789399072; bh=fJh5Pnd5DL/qwxE+WalsUTaJGJt6FooGZcWLpPNnk7E=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=SJBEb+GiYUKwq78ymyy9xZi5YxHSsl3+R12Wq1y0Nsf2/hsIt5f6VR12jG9FLsmoK IEzLRYU4gHRuR3B6UrSWiBzVaqEaDWCvCvmqwrdKIuMYP29tsdN9RjYMUy4sBEBwEO Qwmm0RQ5msDwyuLQ8+6UzfG1pCgJHdctl691Lrfe7MYxV0tWZUErIIggyXeia5YmMK h6wnFZurT6Z7hw2RrQcbTH/vH7UDNmre0Tsy8MF/iVuJWyzO05woCfsOn57z0QCf6a f3RqU+jD2hnz3/Do3nZKKt1jW7hJNKGt/eLLxEZU7UV2k/yAbKikokP9YsJLwlWHCM dm/lMP+3dWi7A== From: "Lorenzo Stoakes (ARM)" Date: Mon, 14 Sep 2026 15:58:00 +0100 Subject: [PATCH v2 40/40] mm/vma: introduce and use vma[_flags]_can_gup() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-40-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@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. 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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 , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin 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=6501; i=ljs@kernel.org; h=from:subject:message-id; bh=3AnqccC2jTUlmIOHAi2JESa1NkBfZlWIxg9a+l0jjPI=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJWcG/RLrydJciw/BS79IsveW9n+2r99rmurBlodmpS+ RRx76h1HaUsDGJcDLJiiizPv4jvDxIJm9d5wd8NZg4rE8gQBi5OAZhIkjvDP93oPv7KUwVZyzmP /Y5JN7v5L+H3keK5W5RUpgfrJzE0uzMynHype2puUKfCJhPhXQtYMu7XXi1Km15XEbP4QomOrJw oLwA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 GUP cannot be used for VMAs which set VMA_IO_BIT - because memory-mapped I/O must not be accessed on the user's behalf - or VMA_PFNMAP_BIT - because PFN maps have no folios which the kernel is permitted to access. Rather than keeping these checks open-coded, abstract them to vma_flags_can_gup() and its VMA wrapper vma_can_gup(). A number of other places make the same check to decide whether a mapping can be populated or accessed as GUP would, so update those too. While here, drop a reference to 'special' and replace a use of the deprecated VMA flags API in vma_dump_size(). No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- fs/coredump.c | 4 ++-- include/linux/mm.h | 29 +++++++++++++++++++++++++++++ mm/gup.c | 7 +++---- mm/hmm.c | 3 +-- mm/memory.c | 14 ++++++++------ mm/mempolicy.c | 3 ++- 6 files changed, 45 insertions(+), 15 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index fb21fb6703dd..9f729c594c47 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1616,8 +1616,8 @@ static unsigned long vma_dump_size(struct vm_area_str= uct *vma, return 0; } =20 - /* Do not dump I/O mapped devices or special mappings */ - if (vma->vm_flags & VM_IO) + /* Do not dump memory-mapped I/O, which may have side effects on read. */ + if (vma_test(vma, VMA_IO_BIT)) return 0; =20 /* By default, dump shared memory if mapped from an anonymous file. */ diff --git a/include/linux/mm.h b/include/linux/mm.h index 5860a3b4dba9..1249e04d7b98 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1777,6 +1777,35 @@ static inline bool vma_is_persistent(const struct vm= _area_struct *vma) return vma_flags_is_persistent(&vma->flags); } =20 +/** + * vma_flags_can_gup() - Do the specified VMA flags permit GUP to access t= he + * mapping's pages? + * @flags: The VMA flags to test. + * + * GUP cannot obtain pages from a PFN map (VMA_PFNMAP_BIT), which may have= no + * struct pages behind it, and must not provide access to memory-mapped I/O + * (VMA_IO_BIT). + * + * Returns: true if GUP may access pages from the mapping, otherwise false. + */ +static inline bool vma_flags_can_gup(const vma_flags_t *flags) +{ + return !vma_flags_test_any(flags, VMA_IO_BIT, VMA_PFNMAP_BIT); +} + +/** + * vma_can_gup() - May GUP obtain pages from @vma? + * @vma: The VMA to test. + * + * See vma_flags_can_gup() for details. + * + * Returns: true if GUP may access pages from the mapping, otherwise false. + */ +static inline bool vma_can_gup(const struct vm_area_struct *vma) +{ + return vma_flags_can_gup(&vma->flags); +} + /** * vma_kernel_pagesize - Default page size granularity for this VMA. * @vma: The user mapping. diff --git a/mm/gup.c b/mm/gup.c index f166acf794e3..8e9ef5ee7498 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1204,7 +1204,7 @@ static int check_vma_flags(struct vm_area_struct *vma= , unsigned long gup_flags) int foreign =3D (gup_flags & FOLL_REMOTE); bool vma_anon =3D vma_is_anonymous(vma); =20 - if (vm_flags & (VM_IO | VM_PFNMAP)) + if (!vma_can_gup(vma)) return -EFAULT; =20 if ((gup_flags & FOLL_ANON) && !vma_anon) @@ -1955,7 +1955,7 @@ int __mm_populate(unsigned long start, unsigned long = len, int ignore_errors) * range with the first VMA. Also, skip undesirable VMA types. */ nend =3D min(end, vma->vm_end); - if (vma->vm_flags & (VM_IO | VM_PFNMAP)) + if (!vma_can_gup(vma)) continue; if (nstart < vma->vm_start) nstart =3D vma->vm_start; @@ -2017,8 +2017,7 @@ static long __get_user_pages_locked(struct mm_struct = *mm, unsigned long start, break; =20 /* protect what we can, including chardevs */ - if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) || - !(vm_flags & vma->vm_flags)) + if (!vma_can_gup(vma) || !(vm_flags & vma->vm_flags)) break; =20 if (pages) { diff --git a/mm/hmm.c b/mm/hmm.c index 2f1e98c6b644..e9569b82a1f0 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -595,8 +595,7 @@ static int hmm_vma_walk_test(unsigned long start, unsig= ned long end, struct hmm_range *range =3D hmm_vma_walk->range; struct vm_area_struct *vma =3D walk->vma; =20 - if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)) && - vma->vm_flags & VM_READ) + if (vma_can_gup(vma) && vma_test(vma, VMA_READ_BIT)) return 0; =20 /* diff --git a/mm/memory.c b/mm/memory.c index 02e9d5d2e279..9e4a70421a6b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2417,11 +2417,11 @@ static bool vm_mixed_zeropage_allowed(struct vm_are= a_struct *vma) * be problematic as soon as the zeropage gets replaced by a different * page due to vma->vm_ops->pfn_mkwrite, because what's mapped would * now differ to what GUP looked up. FSDAX is incompatible to - * FOLL_LONGTERM and VM_IO is incompatible to GUP completely (see - * check_vma_flags). + * FOLL_LONGTERM and memory-mapped I/O is incompatible to GUP completely + * (see vma_can_gup()). */ return vma->vm_ops && vma->vm_ops->pfn_mkwrite && - (vma_is_fsdax(vma) || vma->vm_flags & VM_IO); + (vma_is_fsdax(vma) || vma_test(vma, VMA_IO_BIT)); } =20 static int validate_page_before_insert(struct vm_area_struct *vma, @@ -7116,7 +7116,8 @@ int follow_pfnmap_start(struct follow_pfnmap_args *ar= gs) if (unlikely(address < vma->vm_start || address >=3D vma->vm_end)) goto out; =20 - if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) + /* Only mappings GUP cannot handle are followed here. */ + if (vma_can_gup(vma)) goto out; retry: pgdp =3D pgd_offset(mm, address); @@ -7316,8 +7317,9 @@ static int __access_remote_vm(struct mm_struct *mm, u= nsigned long addr, } =20 /* - * Check if this is a VM_IO | VM_PFNMAP VMA, which - * we can access using slightly different code. + * GUP failed, perhaps because this is a mapping it + * cannot handle (see vma_can_gup()) - such mappings may + * provide access via vm_ops->access() instead. */ bytes =3D 0; #ifdef CONFIG_HAVE_IOREMAP_PROT diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 044ffb4f4128..2fd759e348ca 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2013,7 +2013,8 @@ SYSCALL_DEFINE5(get_mempolicy, int __user *, policy, =20 bool vma_migratable(struct vm_area_struct *vma) { - if (vma->vm_flags & (VM_IO | VM_PFNMAP)) + /* Pages which GUP cannot obtain cannot be migrated either. */ + if (!vma_can_gup(vma)) return false; =20 /* --=20 2.55.0