Re: [PATCH] drm/i915/selftests: Fix build after dma-fence locking rework

[Matthew Brost <matthew.brost@intel.com>]

On Mon, Feb 23, 2026 at 08:13:34PM +0100, Christian König wrote:
> On 2/23/26 18:25, Matthew Brost wrote:
> > The i915_active selftest no longer builds after the dma-fence locking
> > rework because it directly accessed the fence’s spinlock. The helper
> > dma_fence_spinlock() must now be used to obtain the spinlock. Update the
> > selftest to use dma_fence_spinlock() accordingly.
> > 
> > Fixes: 1f32f310a13c ("dma-buf: inline spinlock for fence protection v5")
> > Cc: Christian König <christian.koenig@amd.com>
> > Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> 
> Reviewed-by: Christian König <christian.koenig@amd.com>
> 
> Thanks for the patch and sorry for the noise, just one more question below.
> 
> > ---
> >  drivers/gpu/drm/i915/selftests/i915_active.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/selftests/i915_active.c b/drivers/gpu/drm/i915/selftests/i915_active.c
> > index 52345073b409..9fea2fabeac4 100644
> > --- a/drivers/gpu/drm/i915/selftests/i915_active.c
> > +++ b/drivers/gpu/drm/i915/selftests/i915_active.c
> > @@ -323,9 +323,9 @@ static void active_flush(struct i915_active *ref,
> >  	if (!fence)
> >  		return;
> >  
> > -	spin_lock_irq(fence->lock);
> > +	spin_lock_irq(dma_fence_spinlock(fence));
> 
> Is it guaranteed that this is called from interrupt context? E.g. why is spin_lock_irq() instead of spin_lock_irqsafe() used here?
> 

Idk, this i915 stuff I’ve long intentionally tried to forget to avoid nightmares.

> That's basically the reason why I missed this.
> 

Also, please include the intel-xe list for CI — that will catch issues as well.

We’re making it a bit further now, but we’re hitting a lockdep splat [1].

I can dig into it now; hopefully it’s an easy fix. If not, I may ask for
a revert. Give me an hour or so to look into it and I’ll report back.
But again, please include the intel-xe list for CI on risky DRM common
or dma-buf patches — if the patches apply to drm-tip, CI will run. You
should have permission to trigger this; I believe all AMD emails do.

Matt  

[1] https://intel-gfx-ci.01.org/tree/intel-xe/xe-pw-161999v1/bat-ptl-1/igt@xe_compute@compute-square.html

> Regards,
> Christian.
> 
> >  	__list_del_entry(&active->cb.node);
> > -	spin_unlock_irq(fence->lock); /* serialise with fence->cb_list */
> > +	spin_unlock_irq(dma_fence_spinlock(fence)); /* serialise with fence->cb_list */
> >  	atomic_dec(&ref->count);
> >  
> >  	GEM_BUG_ON(!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags));
>