ovl: fix NULL pointer dereference in copy up warning
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.15.20 by commit e6b678c1a3673de6a5d2f4e22bb725a086a0701a, it was introduced in version v5.15.3 by commit 5cffa333a2b263821561328cc75a3ffc8097d093. For more details please see the references link.