Multiple race conditions in the madvise_remove function in mm/madvise.c in the Linux kernel before 3.4.5 allow local users to cause a denial of service (use-after-free and system crash) via vectors involving a (1) munmap or (2) close system call.
https://bugzilla.redhat.com/show_bug.cgi?id=849734
http://secunia.com/advisories/50633
http://secunia.com/advisories/50732
http://secunia.com/advisories/55055
https://github.com/torvalds/linux/commit/9ab4233dd08036fe34a89c7dc6f47a8bf2eb29eb
http://ubuntu.com/usn/usn-1529-1
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.4.5
http://www.openwall.com/lists/oss-security/2012/08/20/13
http://www.ubuntu.com/usn/USN-1567-1