CVE-2018-1000200

The Linux Kernel versions 4.14, 4.15, and 4.16 has a null pointer dereference which can result in an out of memory (OOM) killing of large mlocked processes. The issue arises from an oom killed process's final thread calling exitmmap(), which calls munlockvmapagesall() for mlocked vmas.This can happen synchronously with the oom reaper's unmappagerange() since the vma's VM_LOCKED bit is cleared before munlocking (to determine if any other vmas share the memory and are mlocked).