From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4D689C98333 for ; Fri, 25 Sep 2026 23:41:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=yI1QnDNpmmMQ9ujwb/HYYMv6EPJgo2PCZbGX+rRPhyM=; b=WjzmArtDgqNSAQ oNknjrRSxP0YEt0iiGE5PLanHd8w8Cy7hwH6h/mxTywxaJyrf/wCYO9gVsWRwadbtVB5MeVNNzvUh 7ewF6AqtkTP09CER1fav03Z5tFpUcoRfBh5/7DxKvg/NVxRES14JL1XlhykFptxasaLBhwMCPnS9V Hg0uQrOkXYm9L/WRD0uQBZDY4R2IhxWr4YBHeUK4ZYtAPoBqqHIIHzHOtZDAmgIBgfdwu4kvWfI6f aeL2d0KGzYBALETTGlkFbmPwx8GOZ9p7jAAA6tlHd1G4beNW/mcU3vmjQj4/pvlyDmXxLQ4lmB5kH PZu9oyNyTKagQT6xYbUA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xAFXQ-0000000EejN-1sTT; Fri, 25 Sep 2026 23:41:08 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xA2eT-0000000D45s-1vV3; Fri, 25 Sep 2026 09:55:33 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id AE0F340AC5; Fri, 25 Sep 2026 09:55:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4C76A1F000FF; Fri, 25 Sep 2026 09:55:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790330132; bh=wHcL5jPNS47s6Ul8XnEo1uFsA8Y0TKv8vyd/Iuc4jW8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=HxJQcEvnuhUOHH3Z6mzmWye1CE1PjDtpVrPBVFbcNDGyG6yBkjOShg1wXTRxmQKyc TCJMHEkTxA8Sxw4HyLR7LdXQhRJb+9udY3QgV8ET7cug6AZBPLxgIFx/TdmYGQ8bVU ptEgwP56FVQ2pJrDbYSWaP8xyRORQKPPWrshPWAAjxwWnAwT2YIoJgfyo9wv4EO7c3 7ozDd+omlnSWJmwSq3s1563JOKXMeNxa13jAxu5Ee20miDdmPGzcEIeZWGgnBBy5y6 eWzAFHQy56s+qgvvgTG8xUGQUmf5tQzyaZcP9CgdenUpWl9R2UycwCgDON1sf75KvU KkanjhxFaUGcw== Date: Fri, 25 Sep 2026 10:55:01 +0100 From: "Lorenzo Stoakes (ARM)" To: Zi Yan Cc: 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 , 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 , 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 Subject: Re: [PATCH v3 05/40] mm/vma: ensure mmap_prepare doesn't set actions on a mergeable vma Message-ID: References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> <20260917-b4-mmap-prepare-vma-flag-sanify-v3-5-4583d8a23bca@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Mailman-Approved-At: Fri, 25 Sep 2026 16:40:51 -0700 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Thu, Sep 24, 2026 at 03:28:10PM -0400, Zi Yan wrote: > On Thu Sep 17, 2026 at 12:22 PM EDT, Lorenzo Stoakes (ARM) wrote: > > 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 d6ed10cefc8f..62f2ce1ad5a1 100644 > > --- a/mm/vma.c > > +++ b/mm/vma.c > > @@ -2809,6 +2809,15 @@ static int mmap_validate(unsigned long prev_start, unsigned long prev_end, > > 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, > > Is it better to say "for VMAs ... after mmap_action_prepare()"? When I > first read this, I wonder why the check is done after > mmap_action_prepare(), which does some work based on action.type. Then, > I realize mmap_action_prepare() changes desc->vma_flags and affect its > mergeablitiy. Ack, good point will update! > > > + * 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 != MMAP_NOTHING)) > > + return -EINVAL; > > + > > return mmap_validate(prev_desc->start, prev_desc->end, > > desc->start, desc->end, > > &prev_desc->vma_flags, &desc->vma_flags); > > > Otherwise, LGTM. > > Reviewed-by: Zi Yan Thanks! > > > -- > Best Regards, > Yan, Zi > -- Cheers, Lorenzo _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv