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Subject: Re: [PATCH] kunit: tool: Force the use of the 'tty' console for UML
To:     Petr Mladek <pmladek@suse.com>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        David Gow <davidgow@google.com>,
        Brendan Higgins <brendanhiggins@google.com>,
        Senozhatsky <sergey.senozhatsky@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com,
        linux-kernel@vger.kernel.org,
        Shuah Khan <skhan@linuxfoundation.org>
References: <20201222073900.3490607-1-davidgow@google.com>
 <20201222111102.GC4077@smile.fi.intel.com>
 <4ae7779c-15c5-0474-5840-44531dcf1d94@linuxfoundation.org>
 <X/SSJQ+I5zEMaYYJ@alley>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <3828c7ee-52b0-42f9-5771-74ef9386756c@linuxfoundation.org>
Date:   Tue, 5 Jan 2021 09:34:33 -0700
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On 1/5/21 9:21 AM, Petr Mladek wrote:
> On Mon 2021-01-04 09:23:57, Shuah Khan wrote:
>> On 12/22/20 4:11 AM, Andy Shevchenko wrote:
>>> On Mon, Dec 21, 2020 at 11:39:00PM -0800, David Gow wrote:
>>>> kunit_tool relies on the UML console outputting printk() output to the
>>>> tty in order to get results. Since the default console driver could
>>>> change, pass 'console=tty' to the kernel.
>>>>
>>>> This is triggered by a change[1] to use ttynull as a fallback console
>>>> driver which -- by chance or by design -- seems to have changed the
>>>> default console output on UML, breaking kunit_tool. While this may be
>>>> fixed, we should be less fragile to such changes in the default.
>>>>
>>>> [1]:
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=757055ae8dedf5333af17b3b5b4b70ba9bc9da4e
>>>
>>> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>>> Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>>>
>>
>> Thank you all. Now in linux-kselftest kunit-fixes branch.
>>
>> Will send this up for rc3.
>>
>> Sorry for the delay - have been away from the keyboard for a
>> bit.
> 
> JFYI, I am not sure that this is the right solution. I am
> looking into it, see
> https://lore.kernel.org/linux-kselftest/X%2FSRA1P8t+ONZFKb@alley/
> for more details.
> 

Thanks Petr. I will hold off on sending the patch up to Linus and
let you find a the right solution.

thanks,
-- Shuah