The futex_wait_requeue_pi function in kernel/futex.c in the Linux kernel before 3.5.1 does not ensure that calls have two different futex addresses, which allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact via a crafted FUTEX_WAIT_REQUEUE_PI command.
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.5.1
http://www.openwall.com/lists/oss-security/2014/05/14/9
https://bugzilla.redhat.com/show_bug.cgi?id=1097746
https://github.com/torvalds/linux/commit/6f7b0a2a5c0fb03be7c25bd1745baa50582348ef