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Howlett" , "Vlastimil Babka (SUSE)" , "Jann Horn" , "Pedro Falcato" , "David Hildenbrand (Red Hat)" , "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" , "Kirill A. Shutemov" , "Doug Gilbert" , "James E . J . Bottomley" , "Martin K. Petersen" , "Jaya Kumar" , "Simona Vetter" , "Helge Deller" , "Sebastian Reichel" , "John Hubbard" , peterx , "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" , "Dave Airlie" , "Will Deacon" , "Aneesh Kumar K.V (Arm)" , "Nicholas Piggin" , "Muchun Song" , "Oscar Salvador" , "Matthew Wilcox" , "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 , 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, "Takashi Iwai" , "Emil Tsalapatis" Message-Id: In-Reply-To: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> Subject: Re: [PATCH v3 00/40] mm: make VMA flag semantics explicit, eliminate VM_SPECIAL X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260925_150704_139996_B8490B5E X-CRM114-Status: GOOD ( 14.63 ) 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 17, 2026, at 18:22, Lorenzo Stoakes (ARM) wrote: > > mm/vma.c | 246 +++++++++++++++++++------- Hi Lorenzo, I see that in linux-next there is a new build failure in some configurations in code that you are changing here: mm/vma.c: In function '__mmap_region': mm/vma.c:3083:1: error: the frame size of 1552 bytes is larger than 1536 bytes [-Werror=frame-larger-than=] I don't immediately see anything that you did that would have introduced something bad that wasn't already there, so it's likely just gone from just below the limit I was using for my testing to just above. The 1536 byte limit is what I use on 64-bit builds with KASAN and otherwise still has a clean build (with a small number of local fixup patches). What I see is that this function has multiple structures on the stack that have nontrivial sizes: VMA_ITERATOR(vmi, mm, addr); /* 104 bytes */ MMAP_STATE(map, mm, &vmi, addr, len,...); /* 384 bytes */ struct vm_area_desc desc; /* 128 bytes */ The config that caused this is https://pastebin.com/raw/5M95qHy5, which is an x86-64 build with CONFIG_KASAN_STACK enabled, and likely a few other configuration options that made it a little worse. KASAN_STACK tends to double the stack size used by structures in order to catch out-of-bounds accesses. If I sprinkle some 'noinline_for_stack' annotations on functions called by __mmap_region(), I can get the size down to 1144 in this config, but that doesn't sound like a great workaround. The large stack usage is potentially harmful if this ends up in call chains that have additional large stack usage (e.g. kmalloc() leading to reclaim). Any ideas for how to reduce it here? Arnd _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv