Re: [PATCH] dma-fence: use correct callback in dma_fence_timeline_name()

[Tvrtko Ursulin]

On 18/06/2026 14:46, Christian König wrote:
> On 6/18/26 14:00, André Draszik wrote:
> > dma_fence_timeline_name() is a wrapper around
> > dma_fence_ops::get_timeline_name(). Since the blamed commit below, it
> > calls an incorrect callback.
> >
> > Update it to restore functionality by calling the intended callback.
> >
> > Fixes: 62918542b7bf ("dma-fence: Fix sparse warnings due __rcu annotations")
> > Signed-off-by: André Draszik <andre.draszik@xxxxxxxxxx>
> I'm like 99% sure we had that already fixed weeks ago, but somehow it looks like that was never merged to drm-misc-fixes.
>
> Anyway Reviewed-by: Christian König <christian.koenig@xxxxxxx>

I was also perplexed and took me some digging to realise what had happened.

The copy-and-paste bug was indeed originally fixed in:

commit 033559473dd3b55558b535aa37b8848c207b5cbb
Author:     Akash Goel <akash.goel@xxxxxxx>
AuthorDate: Tue Oct 21 17:09:51 2025 +0100
Commit:     Tvrtko Ursulin <tursulin@xxxxxxxxxxx>
CommitDate: Fri Oct 24 16:56:37 2025 +0100

    dma-fence: Fix safe access wrapper to call timeline name method


But waaay before that I sent a fix for something else which touched 
those lines not noticing the copy-and-paste, fixing a different issue. 
That one however was not merged until earlier this year:

commit 62918542b7bf08860a60ebbde7654486e0ac0776
Author:     Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
AuthorDate: Mon Jun 16 16:59:52 2025 +0100
Commit:     Christian König <christian.koenig@xxxxxxx>
CommitDate: Mon Feb 9 14:05:20 2026 +0100

    dma-fence: Fix sparse warnings due __rcu annotations

Notice the authored vs commited dates.

I guess it was a silent conflict which overwrote the earlier fix and 
restore the copy-and-paste bug.

Regards,

Tvrtko

> > ---
> >   drivers/dma-buf/dma-fence.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> > index b3bfa6943a8e..5292d714419b 100644
> > --- a/drivers/dma-buf/dma-fence.c
> > +++ b/drivers/dma-buf/dma-fence.c
> > @@ -1202,7 +1202,7 @@ const char __rcu *dma_fence_timeline_name(struct dma_fence *fence)
> >          /* RCU protection is required for safe access to returned string */
> >          ops = rcu_dereference(fence->ops);
> >          if (!dma_fence_test_signaled_flag(fence))
> > -               return (const char __rcu *)ops->get_driver_name(fence);
> > +               return (const char __rcu *)ops->get_timeline_name(fence);
> >          else
> >                  return (const char __rcu *)"signaled-timeline";
> >   }
> >
> > ---
> > base-commit: e2cae00c05d196491c318196792297f2dfbaa02c
> > change-id: 20260618-linux-drm_crtc_fix-267655a1c89f
> >
> > Best regards,
> > --
> > André Draszik <andre.draszik@xxxxxxxxxx>