ring-buffer: Check for NULL cpubuffer in ringbufferwakewaiters()
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 v5.15.78 by commit b5074df412bf3df9d6ce096b6fa03eb1082d05c9, it was introduced in version v5.15.75 by commit 2475de2bc0de17fb1b24c5e90194f84b5ca70d3e. For more details please see the references link.