linux-kernel - [PATCH 4.9 56/66] hwmon: (adt7470) Fix warning on module removal

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Message-Id: <20220510130731.408091772@linuxfoundation.org>
Date:   Tue, 10 May 2022 15:07:46 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Zheyu Ma <zheyuma97@...il.com>,
        Armin Wolf <W_Armin@....de>, Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH 4.9 56/66] hwmon: (adt7470) Fix warning on module removal

From: Armin Wolf <W_Armin@....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@...il.com>
Fixes: 93cacfd41f82 (hwmon: (adt7470) Allow faster removal)
Signed-off-by: Armin Wolf <W_Armin@....de>
Tested-by: Zheyu Ma <zheyuma97@...il.com>
Link: https://lore.kernel.org/r/20220407101312.13331-1-W_Armin@gmx.de
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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;