CVE-2023-53864

In the Linux kernel, the following vulnerability has been resolved:

drm/mxsfb: Disable overlay plane in mxsfb_plane_overlay_atomic_disable()

When disabling overlay plane in mxsfb_plane_overlay_atomic_update(),
overlay plane's framebuffer pointer is NULL.  So, dereferencing it would
cause a kernel Oops(NULL pointer dereferencing).  Fix the issue by
disabling overlay plane in mxsfb_plane_overlay_atomic_disable() instead.