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: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ebba796fa251d042be42b929a2d916ee5c34a49
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.