[PATCH 6.18 260/396] hwmon: (npcm750-pwm-fan): stop fan timer on device detach

6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hongyan Xu <[email protected]>

commit f27f6976ea269219c1259a7c2f8c6dfe782540a3 upstream.

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: [email protected]
Signed-off-by: Hongyan Xu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/hwmon/npcm750-pwm-fan.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/drivers/hwmon/npcm750-pwm-fan.c
+++ b/drivers/hwmon/npcm750-pwm-fan.c
@@ -364,6 +364,11 @@ static void npcm7xx_fan_polling(struct 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)
@@ -1027,6 +1032,12 @@ static int npcm7xx_pwm_fan_probe(struct
 				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;
 		}