Race condition in kernel/events/core.c in the Linux kernel before 4.4 allows local users to gain privileges or cause a denial of service (use-after-free) by leveraging incorrect handling of an swevent data structure during a CPU unplug operation.
https://github.com/torvalds/linux/commit/12ca6ad2e3a896256f086497a7c7406a547ee373
http://www.securityfocus.com/bid/94207