Christ. Multiple reports, none have been closed, no link to changesets.

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200846.

Userspace should never be able to crash the kernel!

In case anyone cares, I have chased this up with very helpful people in #freebsd-bugs on Freenode. I am unable to reproduce this bug myself either on 10.2 or 10.3. Any more info would be appreciated.