Re: [PATCH v2] drm/panthor: Fix the "done_fence is initialized" detection logic

[Nicolas Frattaroli <nicolas.frattaroli@collabora.com>]

On Monday, 9 March 2026 13:43:18 Central European Standard Time Boris Brezillon wrote:
> After commit 541c8f2468b9 ("dma-buf: detach fence ops on signal v3"),
> dma_fence::ops == NULL can't be used to check if the fence is initialized.
> Use dma_fence_was_initialized() instead.
> 
> v2:
> - Use dma_fence_was_initialized() instead of open-coding it
> 
> Cc: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
> Cc: Philipp Stanner <phasta@kernel.org>
> Cc: Christian König <christian.koenig@amd.com>
> Reported-by: Steven Price <steven.price@arm.com>
> Reported-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> Fixes: 541c8f2468b9 ("dma-buf: detach fence ops on signal v3")
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---
>  drivers/gpu/drm/panthor/panthor_sched.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index bd703a2904a1..c15941ebe07a 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -3915,7 +3915,7 @@ static void job_release(struct kref *ref)
>  	if (job->base.s_fence)
>  		drm_sched_job_cleanup(&job->base);
>  
> -	if (job->done_fence && job->done_fence->ops)
> +	if (dma_fence_was_initialized(job->done_fence))
>  		dma_fence_put(job->done_fence);
>  	else
>  		dma_fence_free(job->done_fence);
> 

Tested-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>

This also fixes the refcount underflow for me. Thanks!