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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Guo Ren , Brian Cain , Geert Uytterhoeven , Dinh Nguyen , Simon Schuster , Jonas Bonn , Stefan Kristiansson , Stafford Horne , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Russell King , Vineet Gupta , Michal Simek , Chris Zankel , Max Filippov , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Peter Zijlstra , "David S. Miller" , Andreas Larsson , Richard Henderson , Matt Turner , Magnus Lindholm , Catalin Marinas , Mark Rutland , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Madhavan Srinivasan , Michael Ellerman , "Christophe Leroy (CS GROUP)" , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jason Gunthorpe , John Hubbard , Peter Xu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-openrisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-snps-arc@lists.infradead.org, linux-arch@vger.kernel.org, sparclinux@vger.kernel.org, linux-alpha@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, Hugh Dickins , Qi Zheng Subject: Re: [PATCH 11/12] mm: make userland page table freeing RCU-safe Message-ID: References: <20260901-rcu-pagetable-freeing-v1-0-5456a81c8212@kernel.org> <20260901-rcu-pagetable-freeing-v1-11-5456a81c8212@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260901-rcu-pagetable-freeing-v1-11-5456a81c8212@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 2E3B240014 X-Stat-Signature: nxps8jy93u88ot88z8y4mfz6b7ks7kz1 X-HE-Tag: 1788269620-697702 X-HE-Meta: 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 3uU8BT32 Loa+epfXIU7Y8GF6wo1B2VOpNpob/aT2I1dBokgcH93somJokUL+72fAV2rLAM6ZvIeU+xMFVGz4PnjpQDsvh5BY+2viJpgfyRe7V93Okp+o3N3rXwdGveGqp/pGf53vILlSTfEv/GALKgTMDrF+8ujM2cAZah6jSY0bhd6NNhRlYNZ5RYF6GZdiUKTkpJ49WM8zuDw7WIlcC87x8qaabOxvC9ebkniZGAaXeeHdsNQNj99YD4NvuMl510ail9+l0QNM4IUaxOvlXQgvvok3usIAdfLfQwqusApt2dzetyk1BQmYhgIiNwabJNL308D66RCSy3GuY7uHnwbz6tuGAtnofPhzPZSnpq3Pa Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 01, 2026 at 12:01:31PM +0100, Lorenzo Stoakes (ARM) wrote: > With this change in place the kernel policy is now that all page tables are s/all/userspace/ as subject implies? BTW, what is your take on kernel page tables? Do we want the same policy there. pagetable_free_kernel() is not RCU-safe as it is. > freed after an RCU grace period, and thus it is now safe to unconditionally > perform page table walks under RCU, safe in the knowledge that page tables > will not be freed underneath the walker. -- Kiryl Shutsemau / Kirill A. Shutemov