[PATCH] drm/scheduler: add NULL pointer check for run queue (v2)

[Michel Dänzer]

On 2018-07-16 11:23 AM, Junwei Zhang wrote:
> To check rq pointer before adding entity into it.
> That avoids NULL pointer access in some case.
> 
> v2: move the check to caller
> 
> Suggested-by: Christian König <christian.koenig at amd.com>
> Signed-off-by: Junwei Zhang <Jerry.Zhang at amd.com>
> ---
>  drivers/gpu/drm/scheduler/gpu_scheduler.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> index 16bf446..dac71e3 100644
> --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> @@ -547,6 +547,11 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
>  	if (first) {
>  		/* Add the entity to the run queue */
>  		spin_lock(&entity->rq_lock);
> +		if (!entity->rq) {
> +			DRM_ERROR("Trying to push to a killed entity\n");

This could result in spamming dmesg with this error message. I suggest

		if (WARN_ON_ONCE(!entity->rq)) {

instead, no DRM_ERROR. That will produce a single warning with a backtrace.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer