FreeBSD comes with kldstat command. The kldstat utility or command displays the status of any files dynamically linked into the kernel. And the kldunload utility unloads a file which was previously loaded with lldload command. You can use kldunload command as follows.
Unload a file from the kernel
First login as a root user (use su – or sudo commnad):
Get list of loaded modules/drivers first use following command
To remove module use the following command
The kldstat utility displays the status of any files dynamically linked into the kernel.
kldunload -i ID
Example to unload smbfs module
Type the following command as the root user:
# kldunload smbfs
# kldunload -i 8
Please note that # 8 is module ID obtained using kldstat command.
Force the unload
You can pass -f option to kldunload to force the unload. This ignores error returns to MOD_QUIESCE from the module and implies that the module should be unloaded even if it is currently in use. The users are left to cope as best they can.
# kldunload -f smbfs