ah! found a bug! if you have: static moduledata_t mod_data = { "vnblah3", load, 0 }; and DECLARE_MODULE(vnblah4, mod_data, SI_SUB_DRIVERS, SI_ORDER_ANY); taking into the fact, that vnblah3 has already been loaded before if you do kldload of vnblah4 it will say: May 31 03:32:15 vmnet /kernel: module_register: module vnblah3 already exists! May 31 03:32:15 vmnet /kernel: linker_file_sysinit "vnblah4.ko" failed to register! 17 but kldstat shows: 7 1 0xc0cc8000 2000 vnblah3.ko 8 1 0xc0cca000 2000 vnblah4.ko isn't that considered bad? kldload does show: /sbin/kldload -v ./vnblah4.ko kldload: can't load ./vnblah4.ko: File exists but module_register still loads it looks like that