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

[Junwei Zhang]

To check rq pointer before adding entity into it.
That avoids NULL pointer access in some case.

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 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c b/drivers/gpu/drm/scheduler/gpu_scheduler.c
index 16bf446..5e5268d 100644
--- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
@@ -91,6 +91,10 @@ static void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
 {
 	if (!list_empty(&entity->list))
 		return;
+	if (!rq) {
+		DRM_ERROR("rq is NULL!\n");
+		return;
+	}
 	spin_lock(&rq->lock);
 	list_add_tail(&entity->list, &rq->entities);
 	spin_unlock(&rq->lock);
-- 
1.9.1