Re: [PATCH v1 1/2] drm/sched: cache the timeline name to fix a use-after-free

[Philipp Stanner]

On Wed, 2026-09-02 at 11:20 +0100, Tvrtko Ursulin wrote:
> 
> To collate two replies in one:
> 
> On 02/09/2026 11:07, Philipp Stanner wrote:
> 
> > 
> > The issue here IMO is that we are discussing working around an issue
> > that actually stems from dma_fence not being consistently synchronized,
> > notably because of the ops->release callback being implemented.
> > 
> > ops->release is de facto deprecated, precisely for reasons like these.
> > 
> > If we could get rid of it for sched_fence, dma_fence would take care of
> > the decoupling of the name callbacks.
> > 
> > So that appears worth investigating from my POV.
> 
> I completely agree here but I am just not sure how feasible that would 
> be. We may accept to live with the cross-documentation workaround at 
> least as a start since even if feasible it could be a lot of work to 
> change sched_fence like that.


It should be enough to remove ops->release for the finished_fence for
now, since that's the one typically (always?) shared with userspace.

All that release cb does is drop yet another reference.

I think it's worth an investigation. Maybe 김종혁 can give it a look?


P.