linux-kernel - Re: [BUG] hwmon: (adt7470) warning when removing the module

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <0202486d-cf86-c9d3-04bb-8b1e596462f7@roeck-us.net>
Date:   Thu, 7 Apr 2022 02:23:42 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Armin Wolf <W_Armin@....de>, Zheyu Ma <zheyuma97@...il.com>,
        jdelvare@...e.com
Cc:     linux-hwmon@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [BUG] hwmon: (adt7470) warning when removing the module

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