The get_bitmap_file function in drivers/md/md.c in the Linux kernel before 4.1.6 does not initialize a certain bitmap data structure, which allows local users to obtain sensitive information from kernel memory via a GET_BITMAP_FILE ioctl call.
https://github.com/torvalds/linux/commit/b6878d9e03043695dbf3fa1caa6dfc09db225b16
https://bugzilla.redhat.com/show_bug.cgi?id=1249011
http://www.ubuntu.com/usn/USN-2777-1
http://www.ubuntu.com/usn/USN-2752-1
http://www.ubuntu.com/usn/USN-2751-1
http://www.ubuntu.com/usn/USN-2749-1
http://www.ubuntu.com/usn/USN-2748-1
http://www.ubuntu.com/usn/USN-2732-1
http://www.ubuntu.com/usn/USN-2731-1
http://www.securitytracker.com/id/1033211
http://www.securityfocus.com/bid/76066
http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
http://www.openwall.com/lists/oss-security/2015/07/28/2
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.1.6
http://www.debian.org/security/2015/dsa-3329
http://lists.opensuse.org/opensuse-security-announce/2015-10/msg00009.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-August/164193.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-August/164137.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-August/163711.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-August/163661.html