The ftrace implementation in the Linux kernel before 3.8.8 allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact by leveraging the CAP_SYS_ADMIN capability for write access to the (1) set_ftrace_pid or (2) set_graph_function file, and then making an lseek system call.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=6a76f8c0ab19f215af2a3442870eeb5f0e81998d
lists.opensuse.org/opensuse-security-announce/2013-09/msg00003.html
lists.opensuse.org/opensuse-updates/2013-12/msg00129.html
rhn.redhat.com/errata/RHSA-2013-1051.html
www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.8.8
www.openwall.com/lists/oss-security/2013/04/15/1
www.ubuntu.com/usn/USN-1834-1
www.ubuntu.com/usn/USN-1835-1
www.ubuntu.com/usn/USN-1836-1
www.ubuntu.com/usn/USN-1838-1
bugzilla.redhat.com/show_bug.cgi?id=952197
github.com/torvalds/linux/commit/6a76f8c0ab19f215af2a3442870eeb5f0e81998d