Simplified Steps for Building a Loadable module on -CURRENT

Stefan Bethke stb at
Wed Aug 30 22:26:36 UTC 2006

Am 31.08.2006 um 00:12 schrieb David Christensen:

> I've been able to successfully build drivers in the past as
> loadable modules but I'm getting some kernel panics with -CURRENT
> when installing a module using kldload now where things used to
> work before.

You did nuke /usr/obj, performed a full kernel build (cd /usr/src;  
make buildkernel installkernel), and the module in question that was  
installed alongside your new kernel is *not* panicking the system?

Then what's the panic message, and how exactly are you building your  

> Assume I'm a complete FreeBSD noob for a moment
> (which really isn't that far from the truth) and I want to build
> a driver as a loadable module for testing.  After moving to
> the appropriate directory in the source tree (/usr/src/sys/dev/XXX),
> what steps do I need to follow to build the driver as a module?

That would be /usr/src/sys/modules/<modulename>

So far, just running make there has worked for me just fine.

> Assume for the moment that I have already commented the driver out
> of my kernel configuration file
> (/usr/src/sys/<architecture>/conf/GENERIC)
> and rebuilt and installed that kernel.

If the driver has been compiled into the kernel, kldload will error  
out with EEXISTS. If the system panics, you should provide specifics.

Stefan Bethke <stb at>   Fon +49 170 346 0140

More information about the freebsd-current mailing list