From: Guenter Roeck <linux@roeck-us.net>
To: Armin Wolf <W_Armin@gmx.de>, Zheyu Ma <zheyuma97@gmail.com>,
jdelvare@suse.com
Cc: linux-hwmon@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [BUG] hwmon: (adt7470) warning when removing the module
Date: Thu, 7 Apr 2022 02:23:42 -0700 [thread overview]
Message-ID: <0202486d-cf86-c9d3-04bb-8b1e596462f7@roeck-us.net> (raw)
In-Reply-To: <5f3a3672-6b99-7e24-9003-443c571f2dcc@gmx.de>
On 4/6/22 22:01, Armin Wolf wrote:
> Am 07.04.22 um 05:17 schrieb Zheyu Ma:
>
>> I found a bug when removing the adt7470 module.
>>
>> The following log can reveal it:
>>
>> [ 18.459479] ------------[ cut here ]------------
>> [ 18.459852] do not call blocking ops when !TASK_RUNNING; state=1
>> set at [<ffffffffa006052b>] adt7470_update_thread+0x7b/0x130 [adt7470]
>> [ 18.460857] WARNING: CPU: 7 PID: 365 at kernel/sched/core.c:9660
>> __might_sleep+0x96/0xb0
>> [ 18.461523] Modules linked in: adt7470(-)
>> [ 18.464568] RIP: 0010:__might_sleep+0x96/0xb0
>> [ 18.472577] Call Trace:
>> [ 18.472778] <TASK>
>> [ 18.472957] exit_signals+0x2f/0x3b0
>> [ 18.473251] do_exit+0xcd/0x18c0
>> [ 18.473534] ? __mutex_unlock_slowpath+0x1b8/0x740
>> [ 18.473927] kthread_exit+0x42/0x60
>> [ 18.474212] ? adt7470_detect+0x140/0x140 [adt7470]
>> [ 18.474622] kthread+0x272/0x2e0
>> [ 18.474885] ? adt7470_detect+0x140/0x140 [adt7470]
>> [ 18.475277] ? kthread_blkcg+0xa0/0xa0
>> [ 18.475601] ret_from_fork+0x22/0x30
>> [ 18.475901] </TASK>
>>
>> Regards,
>> Zheyu Ma
>
> Please correct me if i am wrong, but i think the issue lies in adt7470_update_thread()
> leaving the kthread in TASK_INTERRUPTIBLE state when the second check for kthread_should_stop()
> returns true and causes the kthread to exit. Since kthread_exit() might sleep in exit_signals(),
> we get this warning.
> Maybe moving set_current_state(TASK_INTERRUPTIBLE) below the second check for kthread_should_stop()
> would fix the issue?
>
Agreed. Care to send a patch ?
Thanks,
Guenter
prev parent reply other threads:[~2022-04-07 9:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-07 3:17 [BUG] hwmon: (adt7470) warning when removing the module Zheyu Ma
2022-04-07 5:01 ` Armin Wolf
2022-04-07 9:23 ` Guenter Roeck [this message]
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