Not sure what the correct behavior is, so I'm pointing out the inconsistency and letting y'all decide. /etc/defaults/rc.conf says:
devmatch_blacklist="" # List of modules (w/o .ko) to exclude from devmatch.
This appears to be incorrect.
Thanks to https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=253175 I had to disable virtio_random on my new VM at install time. I set
and the module was loaded anyway.
devmatch_blacklist="virtio_random.ko" prevented the module from being loaded.
So, either the script is working wrong or the comment is incorrect.
I checked rc.conf(5) for a tiebreaker, but it doesn't specifically mention .ko.
Duplicate of https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256240 - fixed in https://cgit.freebsd.org/src/commit/?id=b29ebb9c65b350e78aedfc790bfcaf9717059b70 and merged to stable/12 and 13.