From: Tvrtko Ursulin tvrtko.ursulin@igalia.com

Without the locking amdgpu currently can race between amdgpu_ctx_set_entity_priority() (via drm_sched_entity_modify_sched()) and drm_sched_job_arm(), leading to the latter accesing potentially inconsitent entity->sched_list and entity->num_sched_list pair.

v2: * Improve commit message. (Philipp)

Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@igalia.com Fixes: b37aced31eb0 ("drm/scheduler: implement a function to modify sched list") Cc: Christian König christian.koenig@amd.com Cc: Alex Deucher alexander.deucher@amd.com Cc: Luben Tuikov ltuikov89@gmail.com Cc: Matthew Brost matthew.brost@intel.com Cc: David Airlie airlied@gmail.com Cc: Daniel Vetter daniel@ffwll.ch Cc: dri-devel@lists.freedesktop.org Cc: Philipp Stanner pstanner@redhat.com Cc: stable@vger.kernel.org # v5.7+ Reviewed-by: Christian König christian.koenig@amd.com --- drivers/gpu/drm/scheduler/sched_entity.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index 58c8161289fe..ae8be30472cd 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -133,8 +133,10 @@ void drm_sched_entity_modify_sched(struct drm_sched_entity *entity, { WARN_ON(!num_sched_list || !sched_list);

+ spin_lock(&entity->rq_lock); entity->sched_list = sched_list; entity->num_sched_list = num_sched_list; + spin_unlock(&entity->rq_lock); } EXPORT_SYMBOL(drm_sched_entity_modify_sched);