kernel/taskstats.c in the Linux kernel before 3.1 allows local users to obtain sensitive I/O statistics by sending taskstats commands to a netlink socket, as demonstrated by discovering the length of another user's password.
http://lists.opensuse.org/opensuse-security-announce/2012-04/msg00021.html
https://bugzilla.redhat.com/show_bug.cgi?id=716842
http://secunia.com/advisories/48898
https://github.com/torvalds/linux/commit/1a51410abe7d0ee4b1d112780f46df87d3621043