The block subsystem in the Linux kernel before 5.2 has a use-after-free that can lead to arbitrary code execution in the kernel context and privilege escalation, aka CID-c3e2219216c9. This is related to blk_mq_free_rqs and blk_cleanup_queue.
cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.2
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c3e2219216c92919a6bd1711f340f5faa98695e6
security.netapp.com/advisory/ntap-20210629-0006/
sites.google.com/view/syzscope/kasan-use-after-free-read-in-blk_mq_free_rqs
syzkaller.appspot.com/bug?id=36fe241584203cf394d44560a42e3430434f1213