CVE-2026-68181: Undefined Security Weakness

In the Linux kernel, the following vulnerability has been resolved:

mei: bus: access mei_device under device_lock on cleanup

Fix couple of problems in mei_cl_bus_dev_release():

mei_cl_flush_queues() is running without lock. bus->file_list access after mei_dev_bus_put(bus) can become a use-after-free if this was the last reference to bus.

Protect queues cleanup and WARN traversal by device lock there to avoid the concurrent access problems. Move WARN traversal before mei_dev_bus_put(bus).

This file uses bus variable name for mei_device, adjust code of mei_cl_bus_dev_release() to use bus variable too.