Re: [PATCH] tests/acceptance: test hot(un)plug of ccw devices

[Thomas Huth]

On 03/12/2020 19.11, Philippe Mathieu-Daudé wrote:
> On 12/3/20 6:22 PM, Thomas Huth wrote:
>> On 03/12/2020 16.39, Cornelia Huck wrote:
>>> Hotplug a virtio-net-ccw device, and then hotunplug it again.
>>
>> Good idea! ... is it also possible with a pci device?
>>
>>> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
>>> ---
> ...
>>> +        exec_command_and_wait_for_pattern(self, 'dmesg | tail -n 1', 'CRW')
>>
>> That looks like it could be a little bit racy ... what if the kernel outputs
>> another log message by chance, so that tail -n 1 reports that instead.
>>
>> I think it would be better to clear the dmesg log ("dmesg -c") before
>> plugging, and then look at all the new output of "dmesg" without using
>> "tail" afterwards.
> 
> "dmesg --follow"?

Then you'd need to send control-c afterwards to stop it? ... not sure
whether that's such a better solution...

 Thomas