Merge tag 'amd-drm-fixes-5.6-2020-03-26' of git://people.freedesktop.org/~agd5f/linux into drm-fixes

amd-drm-fixes-5.6-2020-03-26:

Scheduler:
- Fix a race condition that could result in a segfault

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200326144538.3937-1-alexander.deucher@amd.com

Author: airlied

drivers/gpu/drm/scheduler/sched_main.c

@@ -661,7 +661,9 @@ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb)
 
 	trace_drm_sched_process_job(s_fence);
 
+	dma_fence_get(&s_fence->finished);
 	drm_sched_fence_finished(s_fence);
+	dma_fence_put(&s_fence->finished);
 	wake_up_interruptible(&sched->wake_up_worker);
 }