[PATCH] drm/amd/display: Fix pointer dereferenced before checking

[Haowen Bai]

The pointer dc is dereferencing pointer plane_state before plane_state
is being null checked. Fix this by assigning plane_state->ctx->dc to
dc only if plane_state is not NULL, otherwise just NULL.

Signed-off-by: Haowen Bai <baihaowen at meizu.com>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 50820e79d3c4..ee22f4422d26 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -3211,7 +3211,7 @@ void dcn10_update_pending_status(struct pipe_ctx *pipe_ctx)
 	struct dc_plane_state *plane_state = pipe_ctx->plane_state;
 	struct timing_generator *tg = pipe_ctx->stream_res.tg;
 	bool flip_pending;
-	struct dc *dc = plane_state->ctx->dc;
+	struct dc *dc = plane_state ? plane_state->ctx->dc : NULL;
 
 	if (plane_state == NULL)
 		return;
-- 
2.7.4