Hello Rodrigo Siqueira,
The patch 135fd1b35690: "drm/amd/display: Reduce stack size" from Jun
21, 2023 (linux-next), leads to the following Smatch static checker
warning:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:8785 amdgpu_dm_atomic_commit_tail()
error: potential null dereference 'dummy_updates'. (kzalloc returns null)
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c
8771 status = dc_stream_get_status(dm_new_crtc_state->stream);
8772
8773 if (WARN_ON(!status))
8774 continue;
8775
8776 WARN_ON(!status->plane_count);
8777
8778 /*
8779 * TODO: DC refuses to perform stream updates without a dc_surface_update.
8780 * Here we create an empty update on each plane.
8781 * To fix this, DC should permit updating only stream properties.
8782 */
8783 dummy_updates = kzalloc(sizeof(struct dc_surface_update) * MAX_SURFACES, GFP_ATOMIC);
This needs a NULL check.
8784 for (j = 0; j < status->plane_count; j++)
--> 8785 dummy_updates[j].surface = status->plane_states[0];
^^^^^^^^^^^^^^^^
Kaplooey!
8786
8787
8788 mutex_lock(&dm->dc_lock);
8789 dc_update_planes_and_stream(dm->dc,
8790 dummy_updates,
8791 status->plane_count,
8792 dm_new_crtc_state->stream,
8793 &stream_update);
8794 mutex_unlock(&dm->dc_lock);
8795 kfree(dummy_updates);
regards,
dan carpenter
