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b=LezzoyJOYE8E5dHI2kTrX2OlVW8csGBo71kbltsEIXgUg7b3ekMDmNG6Bb/sOKisP mBAFZPTtkKRnHQD4pmKo5hbhuMNRyNUbc3HkAm4ILzgTZJrmEO2mPVL83QV0lxShjh p6zpwO8u9X+6fFWJDWQSKUAh5SKN43wkDR4DLRaQ00acWtw+On1hfmIWtMot7YOGsO xUGHWBXkhk/Ujm73YVH8nRDI4SCq8HH8XZzGujRj1bbkqOfqznKCS52wriKePD8x2X bcEt7+QCl4d/m8RdICey8u64NsLkzsUmcx99k6ZMKkmFyW+YpDiE98wvCCVl1FJfyo gAdpWQlO7N+AQ== Date: Tue, 02 Jun 2026 12:09:11 -1000 Message-ID: <8f133924fbf8d259340f3057e505f663@kernel.org> From: Tejun Heo To: bot+bpf-ci@kernel.org, void@manifault.com, arighi@nvidia.com, changwoo@igalia.com, ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, memxor@gmail.com Cc: peterz@infradead.org, catalin.marinas@arm.com, will@kernel.org, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, akpm@linux-foundation.org, david@kernel.org, rppt@kernel.org, emil@etsalapatis.com, sched-ext@lists.linux.dev, bpf@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, eddyz87@gmail.com, yonghong.song@linux.dev, clm@meta.com, ihor.solodrai@linux.dev Subject: Re: [PATCH bpf-next] bpf: Replace scratch PTE atomically when allocating arena pages In-Reply-To: References: <20260601183728.1800490-1-tj@kernel.org> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 3E65420006 X-Stat-Signature: ggjbskt5998z1xs46dez8jgyii5seed8 X-Rspam-User: X-HE-Tag: 1780438154-313290 X-HE-Meta: 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 qSnzjDQJ y1QQiZtFo7cf04AdeOr+eRFWrIsNcKHITS5nIpiNSN/yYsbg/Lp9r2I8vE6sDqsK+bpQCEndf4Sd5ouDq6Jrlh9HhdDp9jN5ZPjpGNiIqqboETJPRGJgW56KHoWx2tiboTXbs/z/iayg6iC1ZRnWKoyQC4i9PjIzfcUuqW50X2swueBGYd3MXp/FujABzFbZ6H9LeAdb+04SbVqTbrXwJq0RDsJv0j0l6vPaRLorYdaNgtlBawABZwE3Y/zJHloUQ2RwB/Ji0XXcd/g55vfDFGwFKyvmYBCVnMPT5wuwVEbCYNt2n4Db19SozP+QQ7HhZoC6uQLMZX9X/7IcARv118fV0A+ZO9ymZUXe5sJNECSbHpyTKMOdBvWhb+++LBnJwHfky Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jun 01, 2026 at 08:15:34PM +0000, bot+bpf-ci@kernel.org wrote: > After the real page is installed without a flush, can that stale > kaddr -> scratch_page translation persist, so that later kernel-side > accesses at kaddr reach the shared per-arena scratch page instead of > the freshly allocated page? It can on x86, but it's harmless: that CPU faulted on an unallocated address and got scratch-recovered, so reaching either the scratch or the real page is fine. No flush needed. Thanks. -- tejun