[PATCH 29/34] drm/amd/display: Add a dc_state NULL check in dc_state_release

[Alex Hung]

From: Allen Pan <allen.pan at amd.com>

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

Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: stable at vger.kernel.org
Reviewed-by: Charlene Liu <charlene.liu at amd.com>
Acked-by: Alex Hung <alex.hung at amd.com>
Signed-off-by: Allen Pan <allen.pan at amd.com>
---
 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 180ac47868c2..5cc7f8da209c 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.
-- 
2.34.1