The futex_lock_pi function in kernel/futex.c in the Linux kernel before 2.6.33-rc7 does not properly manage a certain reference count, which allows local users to cause a denial of service (OOPS) via vectors involving an unmount of an ext3 filesystem.
http://www.vupen.com/english/advisories/2010/0638
http://www.ubuntu.com/usn/USN-914-1
http://www.openwall.com/lists/oss-security/2010/02/11/2
http://www.mandriva.com/security/advisories?name=MDVSA-2010:088
http://secunia.com/advisories/38922
http://lists.opensuse.org/opensuse-security-announce/2010-03/msg00006.html