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

[Greg Kroah-Hartman]

On Wed, Jul 16, 2025 at 12:46:21PM +0200, 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.

As stated later in this thread, this is NOT TRUE AT ALL.

Always explicitly tag things for stable with "cc: stable" for stuff you
want to go to the stable trees.  If you only use "Fixes:" there is no
such guarantee at all.

That goes doubly for the drm trees, where we have a hard enough time
applying the cc: stable@ patches that you all double-commit to different
branches, and we dread every time we see it happen...

thanks,

greg k-h