Description: io_uring: fix fs->users overflow
References:
 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/fs/io_uring.c?h=v5.4.189&id=1a623d361ffe5cecd4244a02f449528416360038
Notes:
 carnil> Issue specific in the 5.4.y branch introduced in 5.4.24 and
 carnil> fixed 5.4.189.
Bugs:
upstream: N/A "Vulnerable code not present"
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"
5.10-bullseye-security: 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"