[PATCH] drm/amd/display: Add a dc_state NULL check in dc_state_release

[Allen Pan]

[How]
Check wheather state is NULL before releasing it.

Cc: Mario Limonciello <mario.limonciello@xxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Charlene Liu <charlene.liu@xxxxxxx>
Acked-by: Alex Hung <alex.hung@xxxxxxx>
Signed-off-by: Allen Pan <allen.pan@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
 drivers/gpu/drm/amd/display/dc/core/dc_state.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_state.c b/drivers/gpu/drm/amd/display/dc/core/dc_state.c
index 180ac47868c22..5cc7f8da209c5 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_state.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_state.c
@@ -334,7 +334,8 @@ static void dc_state_free(struct kref *kref)
 
 void dc_state_release(struct dc_state *state)
 {
-	kref_put(&state->refcount, dc_state_free);
+	if (state != NULL)
+		kref_put(&state->refcount, dc_state_free);
 }
 /*
  * dc_state_add_stream() - Add a new dc_stream_state to a dc_state.
-- 
2.43.0