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([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id k1-20020a05687015c100b000e210c5170fsm3741232oad.6.2022.04.07.02.23.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Apr 2022 02:23:44 -0700 (PDT) Sender: Guenter Roeck Message-ID: <0202486d-cf86-c9d3-04bb-8b1e596462f7@roeck-us.net> Date: Thu, 7 Apr 2022 02:23:42 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [BUG] hwmon: (adt7470) warning when removing the module Content-Language: en-US To: Armin Wolf , Zheyu Ma , jdelvare@suse.com Cc: linux-hwmon@vger.kernel.org, Linux Kernel Mailing List References: <5f3a3672-6b99-7e24-9003-443c571f2dcc@gmx.de> From: Guenter Roeck In-Reply-To: <5f3a3672-6b99-7e24-9003-443c571f2dcc@gmx.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org 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 [] 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]  >> [   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]  >> >> 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