CVE-2026-64112: In the Linux kernel, the following vulnerability has been resolved: rbd: eliminate a race in lock_dwork draining on unm

A race condition (TOCTOU, or time-of-check-time-of-use, where a value changes between being checked and used) exists in the Linux kernel's RBD (RADOS Block Device) driver in how it manages lock_dwork (a delayed work task for exclusive locking). The bug occurs during unmapping when lock_dwork can be re-queued after it should have been permanently canceled, potentially causing the lock acquisition function to run after memory has been freed, leading to crashes.