on Red Hat 8, I can reliably crash lshd, shutting down all active sessions and leaving a pid file around so lshd refuses to restart, by running
dd if=/dev/random bs=1024 count=1|nc localhost >/dev/null
a few times. Sadly, capturing the random sequence that blows down an lshd and replaying it against another one doesn't seem to kill it; different running instances require different replays of the same random to kill them.
Oh well, back to bloody openssh with all its bugs and patches. Drat!
-Bennett