[PATCH 4.19 73/88] hwmon: (adt7470) Fix warning on module removal

Greg Kroah-Hartman
2022-05-10T13:40:03Z

From: Armin Wolf <W_Armin@gmx.de>

commit 7b2666ce445c700b8dcee994da44ddcf050a0842 upstream.

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.

Reported-by: Zheyu Ma <zheyuma97@gmail.com>
Fixes: 93cacfd41f82 (hwmon: (adt7470) Allow faster removal)
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Tested-by: Zheyu Ma <zheyuma97@gmail.com>
Link: https://lore.kernel.org/r/20220407101312.13331-1-W_Armin@gmx.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hwmon/adt7470.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/hwmon/adt7470.c
+++ b/drivers/hwmon/adt7470.c
@@ -33,6 +33,7 @@
#include <linux/kthread.h>
#include <linux/slab.h>
#include <linux/util_macros.h>
+#include <linux/sched.h>

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x2C, 0x2E, 0x2F, I2C_CLIENT_END };
@@ -273,11 +274,10 @@ static int adt7470_update_thread(void *p
adt7470_read_temperatures(client, 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;