[Beowulf] Dirty COW fix for RHEL 6.x

[Kilian Cavalotti]

Dear Beowulfers,

There's no doubt everybody is well aware of CVE-2016-5195 by now, and
that all your systems have been patched several days ago. I mean, all
the systems that run a supported LTS distribution.

Because, in case you're like me, you may have to maintain some
clusters at specific point releases, and you can't really update
everything to the latest LTS version (because of, I don't know,
vendors that provide pre-compiled kernel modules, for instance).

If you're running a Red Hat based distribution such as CentOS, you
probably now that:
1. the upstream fix doesn't apply on your kernel
2. the only supported release is the latest one, meaning that if you
have to stay on say CentOS 6.7 for whatever reason, you don't get a
kernel with the Dirty COW fix. And that is obviously a problem.

So, in case it could help someone, I put together some instructions on
how to apply the fix on your RHEL 6.x kernels (works from 6.5 to 6.8).
Enjoy!

https://github.com/stanford-rc/RHEL6.x-COW

Cheers
-- 
Kilian