CVE-2025-68823 ublk: fix deadlock when reading partition table

In the Linux kernel, the following vulnerability has been resolved: ublk: fix deadlock when reading partition table When one processsuch as udev opens ublk block device e.g., to read the partition table via bdevopen, a deadlock1 can occur: 1. bdevopen grabs disk-openmutex 2. The process issues re...