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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-89a65d17023sm12745086d6.49.2026.03.11.05.04.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Mar 2026 05:04:19 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1w0IIU-000000069iv-3jx0; Wed, 11 Mar 2026 09:04:18 -0300 Date: Wed, 11 Mar 2026 09:04:18 -0300 From: Jason Gunthorpe To: Alice Ryhl Cc: "David Hildenbrand (Arm)" , linux-kernel@vger.kernel.org, "linux-mm @ kvack . org" , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , David Rientjes , Shakeel Butt , "Matthew Wilcox (Oracle)" , Madhavan Srinivasan , Michael Ellerman , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Jarkko Sakkinen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Greg Kroah-Hartman , Arve =?utf-8?B?SGrDuG5uZXbDpWc=?= , Todd Kjos , Christian Brauner , Carlos Llamas , Ian Abbott , H Hartley Sweeten , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Leon Romanovsky , Dimitri Sivanich , Arnd Bergmann , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Andy Lutomirski , Vincenzo Frascino , Eric Dumazet , Neal Cardwell , "David S. Miller" , David Ahern , Jakub Kicinski , Paolo Abeni , Miguel Ojeda , linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-sgx@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, rust-for-linux@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v1 16/16] mm/memory: support VM_MIXEDMAP in zap_special_vma_range() Message-ID: <20260311120418.GU1687929@ziepe.ca> References: <20260227200848.114019-1-david@kernel.org> <20260227200848.114019-17-david@kernel.org> <20260309142954.GM1687929@ziepe.ca> <61df6369-333c-430a-bd18-c5b1acae68ea@kernel.org> 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=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Mar 11, 2026 at 09:38:45AM +0000, Alice Ryhl wrote: > It doesn't really make sense to have multiple binder VMAs. What happens > with Rust Binder is that process A is receiving transactions and has the > VMA mapped once. IIRC the problem is the kernel doesn't guarentee singleton VMAs, userspace can always clone them with fork or something. Did binder solve this somehow? Since you can't assume there is only one VMA the locking becomes a mess to cover all the cases where userspace can trigger a VMA clone. address space deals with this internally. Thus, zap_special_vma_range() is extremely hard to use. Jason