The __oom_reap_task_mm function in mm/oom_kill.c in the Linux kernel before 4.14.4 mishandles gather operations, which allows attackers to cause a denial of service (TLB entry leak or use-after-free) or possibly have unspecified other impact by triggering a copy_to_user call within a certain time window.
https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.4
https://github.com/torvalds/linux/commit/687cb0884a714ff484d038e9190edc874edcf146
https://access.redhat.com/errata/RHSA-2018:2772