[PATCH] hwmon: (adt7470) Fix warning on module removal

From: Armin Wolf
Date: Thu Apr 07 2022 - 06:13:39 EST


When removing the adt7470 module, a warning might be printed:

do not call blocking ops when !TASK_RUNNING; state=1
set at [<ffffffffa006052b>] adt7470_update_thread+0x7b/0x130 [adt7470]

This happens because adt7470_update_thread() can leave the kthread in
TASK_INTERRUPTIBLE state when the kthread is being stopped before
the call of set_current_state(). Since kthread_exit() might sleep in
exit_signals(), the warning is printed.
Fix that by using schedule_timeout_interruptible() and removing
the call of set_current_state().
This causes TASK_INTERRUPTIBLE to be set after kthread_should_stop()
which might cause the kthread to exit.

Compile-tested only.

Reported-by: Zheyu Ma <zheyuma97@xxxxxxxxx>
Fixes: 93cacfd41f82 (hwmon: (adt7470) Allow faster removal)
Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
---
drivers/hwmon/adt7470.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
index fb6d14d213a1..c67cd037a93f 100644
--- a/drivers/hwmon/adt7470.c
+++ b/drivers/hwmon/adt7470.c
@@ -19,6 +19,7 @@
#include <linux/log2.h>
#include <linux/kthread.h>
#include <linux/regmap.h>
+#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/util_macros.h>

@@ -294,11 +295,10 @@ static int adt7470_update_thread(void *p)
adt7470_read_temperatures(data);
mutex_unlock(&data->lock);

- set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop())
break;

- schedule_timeout(msecs_to_jiffies(data->auto_update_interval));
+ schedule_timeout_interruptible(msecs_to_jiffies(data->auto_update_interval));
}

return 0;
--
2.30.2