The init_posix_timers function in kernel/posix-timers.c in the Linux kernel before 2.6.31-rc6 allows local users to cause a denial of service (OOPS) or possibly gain privileges via a CLOCK_MONOTONIC_RAW clock_nanosleep call that triggers a NULL pointer dereference.
https://exchange.xforce.ibmcloud.com/vulnerabilities/52317
http://www.vupen.com/english/advisories/2009/2197
http://www.ubuntu.com/usn/USN-852-1
http://www.openwall.com/lists/oss-security/2009/08/06/2
http://www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.31-rc6
http://secunia.com/advisories/37105
http://secunia.com/advisories/36200
http://lkml.org/lkml/2009/8/4/40