UBUNTU-CVE-2026-90167: High severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: ksmbd: serialize oplock close with pending break ownership close may abort an in-flight oplock break while another breaker already holds an opinfo reference. Releasing pendingbreak wakes that waiter, but without serializing the close transition with bit acquisition it can become a new break owner through the testandsetbit() fast path. It can then overwrite OPLOCKCLOSING with OPLOCKACKWAIT and continue a break for a dying opinfo. Make OPLOCKCLOSING terminal once the opinfo is removed from the inode list. Serialize that transition, pendingbreak acquisition, and OPLOCKACKWAIT setup with an opinfo state lock. A breaker which loses the race releases its ownership and returns -ENOENT. Explicitly wake pendingbreak waiters during close so they can observe the terminal state. Also prevent ACK and timeout paths from replacing OPLOCKCLOSING with OPLOCKSTATENONE.