A flaw was found in the Linux kernel's handling of clearing SELinux attributes on /proc/pid/attr files before 4.9.10. An empty (null) write to this file can crash the system by causing the system to attempt to access unmapped kernel memory.
https://www.debian.org/security/2017/dsa-3791
https://marc.info/?l=selinux&m=148588165923772&w=2
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2618
https://access.redhat.com/errata/RHSA-2017:0933
https://access.redhat.com/errata/RHSA-2017:0932