Local privilege escalation via zone-reporting resource race

Use-after-free in device mapper in affected Linux kernel versions allows local users to gain kernel privileges via a zone-reporting race. During initial zoned device-mapper table setup, dm_blk_report_zones can keep using a dm_table and zone resources after a concurrent failed blk_revalidate_disk_zones call frees them. A local user needs read access to the device-mapper block device while privileged code configures a zoned table; exploitation can disclose kernel memory, corrupt kernel execution, hang device-mapper operations, or panic the host.