5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cong Nguyen [ Upstream commit bb2424c3502cc72292eedade46960c331d5f28fb ] set_fan_speed() writes the control GPIOs one bit at a time. Every other caller locks around it; gpio_fan_shutdown() doesn't. If it races a locked caller, the GPIO writes can interleave and leave the fan at a speed neither caller asked for. Fixes: b95579cd8795 ("hwmon: (gpio-fan) Add a shutdown handler to poweroff the fans") Reported-by: Sashiko AI review Link: https://lore.kernel.org/r/20260830152150.27F5F1F000E9@smtp.kernel.org Assisted-by: Claude:claude-opus-4 Signed-off-by: Cong Nguyen Link: https://patch.msgid.link/20260901155404.1532092-1-congnt264@gmail.com Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin --- drivers/hwmon/gpio-fan.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c index 6d518c10723a0..2039e2b9d3c44 100644 --- a/drivers/hwmon/gpio-fan.c +++ b/drivers/hwmon/gpio-fan.c @@ -562,8 +562,11 @@ static void gpio_fan_shutdown(struct platform_device *pdev) { struct gpio_fan_data *fan_data = platform_get_drvdata(pdev); - if (fan_data->gpios) + if (fan_data->gpios) { + mutex_lock(&fan_data->lock); set_fan_speed(fan_data, 0); + mutex_unlock(&fan_data->lock); + } } #ifdef CONFIG_PM_SLEEP -- 2.53.0