Comment 2 for bug 1594347

ppc64le failure log: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-xenial/xenial/ppc64el/l/linux/20160620_155235@/log.gz

The aslr failures here are showing the same repeated memory layout values for the case when the stack rlimit is set to unlimited, which is a similar failure to CVE-2016-3672 (https://people.canonical.com/~ubuntu-security/cve/2016/CVE-2016-3672.html), which was the same issue but on x86/x86_64 kernels. Looking at the relevant bits of the upstream kernel source, we can see in http://lxr.free-electrons.com/source/arch/powerpc/mm/mmap.c#L96 , when mmap_is_legacy is true (either 32 bit compat mode or unlimited stack size), an unrandomized value is used for the mmap base value.

This is not a regression per se, in that we recently expanded the aslr tests to look for CVE-2016-3672 (but on all arches).