An issue was discovered in fs/io_uring.c in the Linux kernel through 5.11.8. It allows attackers to cause a denial of service (deadlock) because exit may be waiting to park a SQPOLL thread, but concurrently that SQPOLL thread is waiting for a signal to start.
Reference and upstream patch:
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1941770]
Red Hat does not ship io_uring at this point in time in any of the available products.