On 2/23/26 20:20, Matthew Brost wrote:
> 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 <[email protected]>
>>> Signed-off-by: Matthew Brost <[email protected]>
>>
>> Reviewed-by: Christian König <[email protected]>
>>
>> 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].
^^ that actually looks like a bug in dma_fence_chain_enable_signaling() which
was there before the patch set and now just get bubbled up because lockdep can
finally check on it.
Just reverting "dma-buf: use inline lock for the dma-fence-chain" should
silence that again, but it is clearly not the right fix.
> 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.
I did that on an older version of the patch set but never got a report back. My
assumption was that it's working but could be that this actually never ran.
Regards,
Christian.
>
> Matt
>
> [1]
> https://intel-gfx-ci.01.org/tree/intel-xe/xe-pw-161999v1/bat-ptl-1/igt@[email protected]
>
>> 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));
>>
