From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7591C4B7A4E; Thu, 17 Sep 2026 16:24:01 +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=1789662242; cv=none; b=irbtJIiQvOTV767BM+0Q7AAuhj4dSf44ibPyueUSOPuUPLaSzH8XpR1BU6CYSqd3KfJEHyur2wfeTtjsS5GE7y1P+qjS6WHsZo1gIOPgPzDWsrqXVouPZO54lM6d6B0G+JBxF3WEXgrQ97RSiw14xpT/aOG5pILqHjOebN+jI1w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789662242; c=relaxed/simple; bh=Oc6a87+f8ib3EMGGxGSi+EZ7/9tYFaGdj2ExhgkqcQY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=eE6/ZlP4Phyg1C4n/MUuLQ44x/t2SRSqAIf+A/PVOeB3YrJY9chlcTh2E9NtyJb8k0fC4zdjH6YSKbCMSMoxO+tdd8zPTgnXeIz+alXwW9hLJoY0zv3yGder7NTqNL2EMHOQyKd4AV3RSFELGcKzFw9jbeg3v5/9BJniYHWonbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QWkBRqZL; 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="QWkBRqZL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17C491F00893; Thu, 17 Sep 2026 16:23:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789662241; bh=RLuxQ43cC1lLz4lxQslG77OEAHKejqlxyeMy3HZv9pA=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=QWkBRqZLCDNxOzD4bIoFLP6D591QCq0iBOm36/NiXTWdshlgjNwPfC2G3rAcH/Hp2 95W1Lz510usTswgM8JeIJl2rLqPVhR6krFVIK0DmKZo3x31YNW+Qx4QWBqTvnkY8r0 hsT5OU2i/NQTAAr8G7ViMBrzZ4kKUKI4NVr5+JOM7oVllH3UsE9EdOkYD9cq7a9aHe fdXjKWh8vXNmRbEkoPi4X4JucUCcqOeFk5yI+H/Ow2kApn+D0xIECgSozkBztL3jIs FbRx+2bmiYA8JoaZqRiiayTobqBrxEFcMh//EzCGCtoSKabDHc+OT8N03U13EE5eZu WvnejAGNThGTQ== From: "Lorenzo Stoakes (ARM)" Date: Thu, 17 Sep 2026 17:22:11 +0100 Subject: [PATCH v3 02/40] mm/vma: predicate setting mmap_prepare VMA fields on new vma alloc Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-2-4583d8a23bca@kernel.org> References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> In-Reply-To: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@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=1712; i=ljs@kernel.org; h=from:subject:message-id; bh=Oc6a87+f8ib3EMGGxGSi+EZ7/9tYFaGdj2ExhgkqcQY=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLLWCO/78/Jqbd8+paP6cTt/5Z5+U2oglfPFdt+545/uO Sw4xsdzo6OUhUGMi0FWTJHl+Rfx/UEiYfM6L/i7wcxhZQIZwsDFKQATWXaTkaFB3yA7fdtVsSlL Hxos5Zlncfhbg0lew/ZbrwqeRfrfPhbCyLAk6WT6622K9b4/I/g2603cejZIW/5HIC+b8fWAszZ 5EnwA 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 fa784f069da4..4b74b48c29b7 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2894,7 +2894,7 @@ static unsigned long __mmap_region(struct file *file, unsigned long addr, { struct mm_struct *mm = current->mm; struct vm_area_struct *vma = NULL; - bool have_mmap_prepare = file && file->f_op->mmap_prepare; + const bool have_mmap_prepare = file && file->f_op->mmap_prepare; VMA_ITERATOR(vmi, mm, addr); const pgoff_t anon_pgoff = addr >> PAGE_SHIFT; MMAP_STATE(map, mm, &vmi, addr, len, pgoff, anon_pgoff, vma_flags, file); @@ -2937,7 +2937,7 @@ static unsigned long __mmap_region(struct file *file, unsigned long addr, allocated_new = true; } - 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); __mmap_complete(&map, vma); -- 2.55.0