drm_sched_job_arm() is just racing when dereferencing entity and
runqueue.

Add the proper spinlocks.

Cc: [email protected] # v5.16+
Fixes: dbe48d030b28 ("drm/sched: Split drm_sched_job_init")
Signed-off-by: Philipp Stanner <[email protected]>
---
 drivers/gpu/drm/scheduler/sched_main.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c 
b/drivers/gpu/drm/scheduler/sched_main.c
index c39f0245e3a9..7f938f491b6f 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -859,10 +859,16 @@ void drm_sched_job_arm(struct drm_sched_job *job)
 
        BUG_ON(!entity);
        drm_sched_entity_select_rq(entity);
+
+       spin_lock(&entity->lock);
+       spin_lock(&entity->rq->lock);
        sched = entity->rq->sched;
+       spin_unlock(&entity->rq->lock);
+
+       job->s_priority = entity->priority;
+       spin_unlock(&entity->lock);
 
        job->sched = sched;
-       job->s_priority = entity->priority;
 
        drm_sched_fence_init(job->s_fence, job->entity);
 }
-- 
2.49.0

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