GPU DDK - Write UAF due to a race condition caused by insufficient locking in PVRSRVRGXCloseHWPerfClientStreamKM()

Software installed and run as a non-privileged user may conduct improper GPU system calls to cause race condition in hardware performance counters buffer’s destruction path leading to read and/or write UAF.

The race condition in the destruction path could lead to reference counter being decremented in non-atomical way allowing other code paths using a freed object to read and/or write kernel heap memory.