[PATCH] drm/amd/display: Add null check before access structs

[Ma Ke]

In enable_phantom_plane, we should better check null pointer before
accessing various structs.

Fixes: 09a4ec5da92c ("drm/amd/display: Refactor dc_state interface")
Signed-off-by: Ma Ke <make24 at iscas.ac.cn>
---
 drivers/gpu/drm/amd/display/dc/dml2/dml2_mall_phantom.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml2_mall_phantom.c b/drivers/gpu/drm/amd/display/dc/dml2/dml2_mall_phantom.c
index 282d70e2b18a..3d29169dd6bb 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/dml2_mall_phantom.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2/dml2_mall_phantom.c
@@ -750,6 +750,8 @@ static void enable_phantom_plane(struct dml2_context *ctx,
 					ctx->config.svp_pstate.callbacks.dc,
 					state,
 					curr_pipe->plane_state);
+			if (!phantom_plane)
+				return;
 		}
 
 		memcpy(&phantom_plane->address, &curr_pipe->plane_state->address, sizeof(phantom_plane->address));
-- 
2.25.1