BugLink: https://bugs.launchpad.net/bugs/1639345

This reverts commit a76b8ce7 to
apply a more complete fix from linux-next.

CVE-2015-8709
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>