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[95.114.154.97]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-482e28e8fb5sm5723467f8f.29.2026.08.26.20.56.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Aug 2026 20:56:53 -0700 (PDT) Date: Thu, 27 Aug 2026 05:56:21 +0200 From: Karl Mehltretter To: Russell King Cc: Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] ARM: asid: Do not replace active_asids if already 0 Message-ID: References: <20260809180600.6049-1-kmehltretter@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260809180600.6049-1-kmehltretter@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260826_205656_770891_9236A76F X-CRM114-Status: GOOD ( 16.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun, Aug 09, 2026 at 08:06:00PM +0100, Karl Mehltretter wrote: > This patch changes the xchg to cmpxchg so that the active_asids is only > updated if non-zero to avoid a race with an ASID roll-over on a > different CPU. > > Cc: Russell King > Cc: Will Deacon > Signed-off-by: Catalin Marinas > Tested-by: Karl Mehltretter > Signed-off-by: Karl Mehltretter > --- > This is similar to the arm64 patch [1], with the difference that > non-relaxed (cmp)xchg is used as in the existing ARM code. > > This is a resubmission of Catalin Marinas' original 2018 patch. The > original submission was not merged, and the ARM32 equivalent of the arm64 > ASID rollover fix remains missing. > Just a friendly ping in case this got missed. Thanks, Karl