[LinuxCNC/linuxcnc Issue#451] mesa_7i65 comp causes kernel panic

Here are the steps I follow to reproduce the issue:

Run Linuxcnc with the halfile/hardware for mesa_7i65 component

This is what I expected to happen:

Run normally

This is what happened instead:

Causes a kernel panic about 1/3 time you launch or leave LinuxCNC
Driver seems to work properly if it launches OK

It worked properly before this:

Not sure 2.8 also reportedly has this issue

Information about my hardware and software:

LinucCNC 2.7.12 or LinuxCNC 2.7.14

2.7.12 binary version is from linuxcnc.org
2.7.14 binary version is built from source locally
Hardware is 5I20 card + 7I65