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Wong" , "Mark M. Hoffman" , linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, sashiko-bot@kernel.org Subject: Re: [hwmon PATCH v2 7/8] hwmon: (adt7470) Fix divide-by-zero TOCTOU crash in fan speed read Message-ID: <0ca13015-87f4-41c5-bc01-1ae66d8af721@roeck-us.net> References: <20260727-adt7470_fixes-v2-0-598e38a46ba6@gmail.com> <20260727-adt7470_fixes-v2-7-598e38a46ba6@gmail.com> 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: <20260727-adt7470_fixes-v2-7-598e38a46ba6@gmail.com> On Mon, Jul 27, 2026 at 09:22:23PM -0300, Luiz Angelo Daros de Luca wrote: > If the fan data becomes 0 between the FAN_DATA_VALID() check and the > FAN_PERIOD_TO_RPM() conversion, it will result in a divide-by-zero crash > due to a race with a concurrent update of the cached fan value. > > Fix a TOCTOU issue by reading fan data once. > > Reported-by: sashiko-bot@kernel.org > Closes: https://lore.kernel.org/r/20260727034929.E29B71F000E9@smtp.kernel.org/ > Fixes: fc958a61ff6d ("hwmon: (adt7470) Convert to devm_hwmon_device_register_with_info API") > Signed-off-by: Luiz Angelo Daros de Luca Applied. Thanks, Guenter