[PATCH] drm/sched: Remove optimization that causes hang when killing dependent jobs

[Christian König]

On 16.07.25 12:46, Philipp Stanner wrote:
> +Cc Greg, Sasha
> 
> On Wed, 2025-07-16 at 12:40 +0200, Michel Dänzer wrote:
>> On 16.07.25 11:57, Philipp Stanner wrote:
>>> On Wed, 2025-07-16 at 09:43 +0000, cao, lin wrote:
>>>>
>>>> Hi Philipp,
>>>>
>>>>
>>>> Thank you for the review. I found that this optimization was
>>>> introduced 9 years ago in commit
>>>> 777dbd458c89d4ca74a659f85ffb5bc817f29a35 ("drm/amdgpu: drop a
>>>> dummy
>>>> wakeup scheduler").
>>>>
>>>>
>>>> Given that the codebase has undergone significant changes over
>>>> these
>>>> 9 years. May I ask if I still need to include the Fixes: tag?
>>>
>>> Yes. It's a helpful marker to see where the problem comes from, and
>>> it
>>> adds redundancy helping the stable-kernel maintainers in figuring
>>> out
>>> to which kernels to backport it to.
>>>
>>> If stable can't apply a patch to a very old stable kernel because
>>> the
>>> code base changed too much, they'll ping us and we might provide a
>>> dedicated fix.
>>>
>>> So like that:
>>>
>>> Cc: stable at vger.kernel.org # v4.6+
>>> Fixes: 777dbd458c89 ("drm/amdgpu: drop a dummy wakeup scheduler")
>>
>> FWIW, Fixes: alone is enough for getting backported to stable
>> branches, Cc: stable is redundant with it.
> 
> Both are used all the time together, though. And the official
> documentation does not list dropping Cc: stable as a valid option in
> this regard
> 
> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-1
> 
> 
> As long as the official documentation demands it, I'm not willing to
> drop it. If the docu were to be changed, that would be fine by me, too.

As far as I understand "CC: stable" and "Fixes:" tags are to handle two distinct use cases.

"CC: stable..." means please backport, eventually with a kernel version and/or necessary pre-requisites.

"Fixes:" only backport if you have this patch in your tree as well. In other words it is a restriction when to backport something.

Would be nice if somebody could clarify if my understanding here is accurate.

Regards,
Christian.

> 
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> P.
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