[bug report] drm/amd/display: Build stream update and plane updates in dm

[Bhawanpreet Lakha]

I had a patch ready and was going to send it in the next promotion 
patches. Will send it soon.


Bhawan


On 2018-09-28 04:32 AM, Dan Carpenter wrote:
> Hello Bhawanpreet Lakha,
>
> The patch a87fa9938749: "drm/amd/display: Build stream update and
> plane updates in dm" from Aug 20, 2018, leads to the following static
> checker warning:
>
> 	drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:5190 dm_determine_update_type_for_commit()
> 	error: potential null dereference 'surface'.  (kzalloc returns null)
>
> drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c
>    5153          int i, j, num_plane;
>    5154          struct drm_plane_state *old_plane_state, *new_plane_state;
>    5155          struct dm_plane_state *new_dm_plane_state, *old_dm_plane_state;
>    5156          struct drm_crtc *new_plane_crtc, *old_plane_crtc;
>    5157          struct drm_plane *plane;
>    5158
>    5159          struct drm_crtc *crtc;
>    5160          struct drm_crtc_state *new_crtc_state, *old_crtc_state;
>    5161          struct dm_crtc_state *new_dm_crtc_state, *old_dm_crtc_state;
>    5162          struct dc_stream_status *status = NULL;
>    5163
>    5164          struct dc_surface_update *updates = kzalloc(MAX_SURFACES * sizeof(struct dc_surface_update), GFP_KERNEL);
>                                            ^^^^^^^^^^^^^^^^^
>    5165          struct dc_plane_state *surface = kzalloc(MAX_SURFACES * sizeof(struct dc_plane_state), GFP_KERNEL);
>                                         ^^^^^^^^^^^^^^^^^
> No checks for NULL.
>
>    5166          struct dc_stream_update stream_update;
>    5167          enum surface_update_type update_type = UPDATE_TYPE_FAST;
>    5168
>    5169
>    5170          for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
>    5171                  new_dm_crtc_state = to_dm_crtc_state(new_crtc_state);
>    5172                  old_dm_crtc_state = to_dm_crtc_state(old_crtc_state);
>    5173                  num_plane = 0;
>    5174
>    5175                  if (new_dm_crtc_state->stream) {
>    5176
>    5177                          for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, j) {
>    5178                                  new_plane_crtc = new_plane_state->crtc;
>    5179                                  old_plane_crtc = old_plane_state->crtc;
>    5180                                  new_dm_plane_state = to_dm_plane_state(new_plane_state);
>    5181                                  old_dm_plane_state = to_dm_plane_state(old_plane_state);
>    5182
>    5183                                  if (plane->type == DRM_PLANE_TYPE_CURSOR)
>    5184                                          continue;
>    5185
>    5186                                  if (!state->allow_modeset)
>    5187                                          continue;
>    5188
>    5189                                  if (crtc == new_plane_crtc) {
>    5190                                          updates[num_plane].surface = &surface[num_plane];
>    5191
>    5192                                          if (new_crtc_state->mode_changed) {
>    5193                                                  updates[num_plane].surface->src_rect =
>    5194                                                                          new_dm_plane_state->dc_state->src_rect;
>    5195                                                  updates[num_plane].surface->dst_rect =
>    5196                                                                          new_dm_plane_state->dc_state->dst_rect;
>    5197                                                  updates[num_plane].surface->rotation =
>
> regards,
> dan carpenter