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Mon, 24 Nov 2025 11:45:38 -0800 (PST) Sender: Guenter Roeck Date: Mon, 24 Nov 2025 11:45:36 -0800 From: Guenter Roeck To: Gui-Dong Han Cc: steve.glendinning@shawell.net, linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, baijiaju1990@gmail.com Subject: Re: [PATCH] hwmon: (emc2103) Add locking to avoid TOCTOU Message-ID: <0228fa73-4af2-4dd3-a607-a555afc664e9@roeck-us.net> References: <20251124165508.4667-1-hanguidong02@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: <20251124165508.4667-1-hanguidong02@gmail.com> On Tue, Nov 25, 2025 at 12:55:08AM +0800, Gui-Dong Han wrote: > The functions fan1_input_show and fan1_target_show check shared data for > zero before using it as a divisor. These accesses are currently > lockless. If the data changes to zero between the check and the > division, it causes a divide-by-zero error. > > Explicitly acquire the update lock around these checks and calculations > to ensure the data remains stable, preventing Time-of-Check to > Time-of-Use (TOCTOU) race conditions. > > Link: https://lore.kernel.org/all/CALbr=LYJ_ehtp53HXEVkSpYoub+XYSTU8Rg=o1xxMJ8=5z8B-g@mail.gmail.com/ > Signed-off-by: Gui-Dong Han > --- Applied. Thanks, Guenter