[PATCH 3/6] drm/amdgpu: screen freeze and userq driver crash

[Christian König]

Am 30.08.24 um 20:43 schrieb Arunpravin Paneer Selvam:
> Screen freeze and userq fence driver crash while playing Xonotic
>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c | 12 +++++++-----
>   1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> index d2e1d0d0f29f..8a3b5374cc1a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> @@ -187,6 +187,7 @@ int amdgpu_userq_fence_create(struct amdgpu_usermode_queue *userq,
>   	struct amdgpu_userq_fence_driver *fence_drv;
>   	struct amdgpu_userq_fence *userq_fence;
>   	struct dma_fence *fence;
> +	unsigned long flags;
>   
>   	fence_drv = userq->fence_drv;
>   	if (!fence_drv)
> @@ -230,14 +231,15 @@ int amdgpu_userq_fence_create(struct amdgpu_usermode_queue *userq,
>   		}
>   	}
>   
> -	spin_lock(&fence_drv->fence_list_lock);
>   	/* Check if hardware has already processed the job */
> -	if (!dma_fence_is_signaled(fence))
> +	if (!dma_fence_is_signaled(fence)) {
> +		spin_lock_irqsave(&fence_drv->fence_list_lock, flags);

As far as I can see that still won't work correctly since you can't 
guarantee that the fence doesn't signal in between testing and grabbing 
the lock.

Christian.



>   		list_add_tail(&userq_fence->link, &fence_drv->fences);
> -	else
> -		dma_fence_put(fence);
>   
> -	spin_unlock(&fence_drv->fence_list_lock);
> +		spin_unlock_irqrestore(&fence_drv->fence_list_lock, flags);
> +	} else {
> +		dma_fence_put(fence);
> +	}
>   
>   	*f = fence;
>