CVE-2018-3639 (powerpc)
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mauricio: backport to Ubuntu 16.04 linux_4.4.0-124.148]
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>