linux-kernel - Re: [PATCH for-next 1/3] selftests/watchdog: add count parameter for watchdog-test

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Message-ID: <54cbf018-eba1-4227-b464-78bfa41fa4ae@linuxfoundation.org>
Date: Sun, 27 Oct 2024 23:31:53 -0600
From: Shuah Khan <skhan@...uxfoundation.org>
To: "Zhijian Li (Fujitsu)" <lizhijian@...itsu.com>,
 "linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>
Cc: "shuah@...nel.org" <shuah@...nel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH for-next 1/3] selftests/watchdog: add count parameter for
 watchdog-test

On 10/27/24 22:02, Zhijian Li (Fujitsu) wrote:
> 
> 
> On 28/10/2024 11:29, Shuah Khan wrote:
>> On 10/27/24 18:50, Zhijian Li (Fujitsu) wrote:
>>>
>>>
>>> On 27/10/2024 08:28, Shuah Khan wrote:
>>>> On 10/24/24 19:39, Li Zhijian wrote:
>>>>> Currently, watchdog-test keep running until it gets a SIGINT. However,
>>>>> when watchdog-test is executed from the kselftests framework, where it
>>>>> launches test via timeout which will send SIGTERM in time up. This could
>>>>> lead to
>>>>> 1. watchdog haven't stop, a watchdog reset is triggered to reboot the OS
>>>>>       in silent.
>>>>> 2. kselftests gets an timeout exit code, and judge watchdog-test as
>>>>>      'not ok'
>>>>>
>>>> This test isn't really supposed to be run from kselftest framework.
>>>> This is the reason why it isn't included in the default run.
>>>
>>> May I know what's the default run, is it different from `make run_tests` ?
>>
>> No it isn't. "make kselftest" runs only the targets mentioned in the
>> selftests Makefile. That is considered the kselftest default run.
> 
> Hey, Shuah,
> 
> 
> Thanks for your explanation.
> If that is the case, I do not have an urgent need for the current patch, expect
> I'd like to avoid the reboot issue after an accidentally `make run_tests`
> 
> Some changes are make as below, please take a look. I will send it out we reach a consensus.
> 
> 
> commit 2296f9d88fde4921758a45bf160a7f1b9d4678a0 (HEAD)
> Author: Li Zhijian <lizhijian@...itsu.com>
> Date:   Mon Oct 28 11:54:03 2024 +0800
> 
>       selftests/watchdog-test: Fix system accidentally reset after watchdog-test
>       
>       After `make run_tests` to run watchdog-test, a system reboot would
>       happen due to watchdog not stop.
>       ```

The system shouldn't reboot just because watchdog test is left running.
watchdog test keeps calling ioctl() with WDIOC_KEEPALIVE to make sure
the watchdog card timer is reset.

If you are seeing reboots, that means watchdog test couldn't reset the
timer. This usually mean system is unresponsive or something is wrong
with the watchdog card on your system.

This is the behavior you would expect from a watchdog timer. Does your
system have a watchdog card ot or you enabling softdog module?

Either way there is some other reason for the system reboot.

thanks,
-- Shuah