* Get your coredump.

* Start kgdb: `kgdb /var/crash/kernel.X /var/crash/vmcore.X`.

* Load some handy helper commands when you're at the kgdb prompt: `source /usr/src/test/debug/gdb.kernel`.

* Get the kld statistics from the kernel: `kldstat` at the kgdb prompt.

* Background kgdb (^Z).

* Execute a helper utility to create another gdb script: `asf -s /modules`.

* Paste the output from the kgdb 'kldstat' command above.

* Signal asf that you're ready (^D).

* Foreground kgdb again: `fg`.

* Load the gdb script created by asf above to load kmod symbols: `source .asf` at the kgdb prompt.

* Print, list, backtrace to your heart's content! Be sure to have debug symbols compiled with your modules though ;).