[Intel-gfx] [PATCH 8/8] drm/i915: NULL check of unpin_work

[Tomas Elf]

On 09/10/2015 11:44, Chris Wilson wrote:
> On Fri, Oct 09, 2015 at 11:30:34AM +0100, Tomas Elf wrote:
>> On 09/10/2015 08:46, Chris Wilson wrote:
>>> On Thu, Oct 08, 2015 at 07:31:40PM +0100, Tomas Elf wrote:
>>>> Avoid NULL pointer exceptions in the display driver for certain critical cases
>>>> when unpin_work has turned out to be NULL.
>>>
>>> Nope, the machine reached a point where it cannot possibly reach, we
>>> want the OOPS.
>>> -Chris
>>>
>>
>> Really? Because if I have this in there I can actually run the
>> long-duration stability tests for 12+ hours rather than just a few
>> hours (it doesn't happen all the time but I've seen it at least
>> once). But, hey, if you want to investigate the reason why we have a
>> NULL there then go ahead. I guess I'll just have to carry this patch
>> for as long as my machine crashes during my TDR testing.
>
> You've sat on a critical bug for how long? There's been one recent
> report that appears to be fallout from Tvrtko's context cleanup, but
> nothing older, in public at least.
> -Chris
>

Do people typically try to actively hang their machines several times a 
minute for a 12+ hours at a time? If not then maybe that's why they 
haven't seen this.

I haven't sat on anything, this has been part of my error state capture 
improvement patches which I've intended to upstream for several months 
now. I consider this part of the overall stability issue and grouped it 
together with all the other patches necessary to make the machine not 
crash for the duration of my test. I would've upstreamed this series a 
long time ago if I had actually been given time to work on it but that's 
another discussion.

Thanks,
Tomas