Race condition in the get_task_ioprio function in block/ioprio.c in the Linux kernel before 4.6.6 allows local users to gain privileges or cause a denial of service (use-after-free) via a crafted ioprio_get system call.
https://github.com/torvalds/linux/commit/8ba8682107ee2ca3347354e018865d8e1967c5f4
http://www.securityfocus.com/bid/94135
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.6.6