xen/xenbus: don't let xenbusgrantring() remove grants in error case
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 v4.19.234 by commit 8d521d960aef22781ff499e16899c30af899de8d. For more details please see the references link.