A NULL pointer dereference issue was found in the Linux kernel. If the close() and fchownat() system calls share a socket file descriptor as an argument, then the two calls can race and trigger a NULL pointer dereference leading to a system crash and a denial of service.
An upstream patch:
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1590216]
This issue has been addressed in the following products:
Red Hat Enterprise Linux 7
Via RHSA-2018:2948 https://access.redhat.com/errata/RHSA-2018:2948