[enntwo]

The module used in the article was simply to demo the exploit. It could be used against any null deference vulnerabilities found in current kernels (the article uses a recent one as an example as well).

The point of the article is to demonstrate why they are dangerous, and how they are exploited, not to provide an example of a current vulnerabilty.

If you found such a vulnerabilty (which does happen, hence the example given in the article) you would be able to use this technique to root. (Assuming you were able to circumvent mid address limition on mmap, which the author says used to be, and possibly still is feasible.)

The title seems to accurately describe the article, given a "kernel NULL pointer vulnerabilty" here is how to root it.