[PATCH 4/5] drm/amd/sched: NULL out the s_fence field after run_job

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

amd_sched_process_job drops the fence reference, so NULL out the s_fence
field before adding it as a callback to guard against accidentally using
s_fence after it may have be freed.

Signed-off-by: Nicolai Hähnle <nicolai.haehnle at amd.com>
Acked-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
index e793312e351c..54eb77cffd9b 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
@@ -604,20 +604,23 @@ static int amd_sched_main(void *param)
 		if (!sched_job)
 			continue;
 
 		s_fence = sched_job->s_fence;
 
 		atomic_inc(&sched->hw_rq_count);
 		amd_sched_job_begin(sched_job);
 
 		fence = sched->ops->run_job(sched_job);
 		amd_sched_fence_scheduled(s_fence);
+
+		sched_job->s_fence = NULL;
+
 		if (fence) {
 			s_fence->parent = dma_fence_get(fence);
 			r = dma_fence_add_callback(fence, &s_fence->cb,
 						   amd_sched_process_job);
 			if (r == -ENOENT)
 				amd_sched_process_job(fence, &s_fence->cb);
 			else if (r)
 				DRM_ERROR("fence add callback failed (%d)\n",
 					  r);
 			dma_fence_put(fence);
-- 
2.11.0