[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 <mak...@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