hwmon: (npcm750-pwm-fan): stop fan timer on device detach

When a fan tach channel is present, npcm7xx_pwm_fan_probe() starts
fan_timer. The timer callback polls tach state and rearms the timer, but
the driver has no remove callback or devm cleanup action to stop it. On
device detach, the devm-managed driver data and I/O mappings can be
released while the timer is still pending or running.

Register a devm cleanup action before starting the timer and shut the
timer down synchronously from that action.

This issue was found by a static analysis tool.

Fixes: f1fd4a4db777 ("hwmon: Add NPCM7xx PWM and Fan driver")
Cc: stable@vger.kernel.org
Signed-off-by: Hongyan Xu <getshell@seu.edu.cn>
Link: https://lore.kernel.org/r/20260729100116.790-1-getshell@seu.edu.cn
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/npcm750-pwm-fan.c b/drivers/hwmon/npcm750-pwm-fan.c
index aea0b8659f5f6335bf3480a339de991ce0c33f68..6ff2a6bc06c14edce16179abda2079fb674698cc 100644 (file)
--- a/drivers/hwmon/npcm750-pwm-fan.c
+++ b/drivers/hwmon/npcm750-pwm-fan.c
@@ -358,6 +358,11 @@ static void npcm7xx_fan_polling(struct timer_list *t)
        add_timer(&data->fan_timer);
 }
 
+static void npcm7xx_fan_cleanup(void *timer)
+{
+       timer_shutdown_sync(timer);
+}
+
 static inline void npcm7xx_fan_compute(struct npcm7xx_pwm_fan_data *data,
                                       u8 fan, u8 cmp, u8 fan_id, u8 flag_int,
                                       u8 flag_mode, u8 flag_clear)
@@ -1020,6 +1025,12 @@ static int npcm7xx_pwm_fan_probe(struct platform_device *pdev)
                                msecs_to_jiffies(NPCM7XX_FAN_POLL_TIMER_200MS);
                        timer_setup(&data->fan_timer,
                                    npcm7xx_fan_polling, 0);
+                       ret = devm_add_action_or_reset(dev,
+                                                      npcm7xx_fan_cleanup,
+                                                      &data->fan_timer);
+                       if (ret)
+                               return ret;
+
                        add_timer(&data->fan_timer);
                        break;
                }