[PATCH] drm/sched: Fix race in drm_sched_entity_select_rq()

[Philipp Stanner <phasta@kernel.org>]

In a past bug fix it was forgotten that entity access must be protected
by the entity lock. That's a data race and potentially UB.

Move the spin_unlock() to the appropriate position.

Cc: stable@vger.kernel.org # v5.13+
Fixes: ac4eb83ab255 ("drm/sched: select new rq even if there is only one v3")
Signed-off-by: Philipp Stanner <phasta@kernel.org>
---
 drivers/gpu/drm/scheduler/sched_entity.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 5a4697f636f2..aa222166de58 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -552,10 +552,11 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
 		drm_sched_rq_remove_entity(entity->rq, entity);
 		entity->rq = rq;
 	}
-	spin_unlock(&entity->lock);
 
 	if (entity->num_sched_list == 1)
 		entity->sched_list = NULL;
+
+	spin_unlock(&entity->lock);
 }
 
 /**
-- 
2.49.0