Description: block: free sched's request pool in blk_cleanup_queue
References:
 https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-blk_mq_free_rqs
 https://syzkaller.appspot.com/bug?id=36fe241584203cf394d44560a42e3430434f1213
Notes:
 carnil> Commit fixes 47cdee29ef9d ("block: move blk_exit_queue into
 carnil> __blk_release_queue") in 5.2-rc3.
Bugs:
upstream: released (5.2-rc4) [c3e2219216c92919a6bd1711f340f5faa98695e6]
5.10-upstream-stable: N/A "Vulnerable code not present"
4.19-upstream-stable: N/A "Vulnerable code not present"
4.9-upstream-stable: N/A "Vulnerable code not present"
sid: N/A "Vulnerable code not present"
4.19-buster-security: N/A "Vulnerable code not present"
4.9-stretch-security: N/A "Vulnerable code not present"