[PATCH v2 2/2] drm/xe: Add a WARN_ON for NULL job in xe_sync_entry_signal

[Michal Wajdeczko]

On 18.03.2024 17:43, Nirmoy Das wrote:
> Add a warn for NULL job when sync->type is
> DRM_XE_SYNC_TYPE_USER_FENCE. This should be a programming
> error and should never happen so warn and let the kernel crash
> if that ever happens.

IMO adding WARN and then let kernel crash is pointless as you will have
almost exactly the same report as from NPD

for programming errors we should xe_assert() that will provide necessary
hint during code refactor but will be compiled on production builds

only if you feel that that job could be still (but unlikely) NULL then
you should use drm_WARN/xe_gt_WARN and provide necessary fallback

> 
> Cc: Matthew Auld <matthew.auld at intel.com>
> Cc: Matthew Brost <matthew.brost at intel.com>
> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_sync.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_sync.c b/drivers/gpu/drm/xe/xe_sync.c
> index 02c9577fe418..247505c3478d 100644
> --- a/drivers/gpu/drm/xe/xe_sync.c
> +++ b/drivers/gpu/drm/xe/xe_sync.c
> @@ -255,6 +255,7 @@ void xe_sync_entry_signal(struct xe_sync_entry *sync, struct xe_sched_job *job,
>  			dma_fence_put(fence);
>  		}
>  	} else if (sync->type == DRM_XE_SYNC_TYPE_USER_FENCE) {
> +		XE_WARN_ON(!job);
>  		job->user_fence.used = true;
>  		job->user_fence.addr = sync->addr;
>  		job->user_fence.value = sync->timeline_value;