[PATCH 4.20 013/352] drm/amd/display: Fix potential nullptr error

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 4f7129112c2a30331f3045a42026fad82e6cb72b ]

[Why]
Fix surface/plane potential nullptr

[How]
add null check

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx>
Reviewed-by: Aric Cyr <Aric.Cyr@xxxxxxx>
Acked-by: Leo Li <sunpeng.li@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 3118ae0e7a87..315a245aedc2 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -5333,6 +5333,12 @@ enum surface_update_type dm_determine_update_type_for_commit(struct dc *dc, stru
 	struct dc_stream_update stream_update;
 	enum surface_update_type update_type = UPDATE_TYPE_FAST;
 
+	if (!updates || !surface) {
+		DRM_ERROR("Plane or surface update failed to allocate");
+		/* Set type to FULL to avoid crashing in DC*/
+		update_type = UPDATE_TYPE_FULL;
+		goto ret;
+	}
 
 	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
 		new_dm_crtc_state = to_dm_crtc_state(new_crtc_state);
-- 
2.19.1