Setting up netconsole
Assume we have two computers on the same network.
The machine with a problem:
IP address: 192.168.1.1
And a second machine..
IP address: 192.168.1.2 MAC address of eth0: 00:11:22:33:44:55
The debugger
On a different machine than the one you are seeing the problem, you need to run nc -l -u 6666
This will listen on udp port 6666 for any messages.
The debugee
On the machine that you're trying to debug a problem, run (as root) modprobe netconsole netconsole=4444@192.168.1.1/eth0,6666@192.168.1.2/00:11:22:33:44:55
If you replace the IP/MAC addresses with those relevant to your machines/network in the command above, you should see messages appearing on the debugging machine.
For more information on netconsole, see http://www.mjmwired.net/kernel/Documentation/networking/netconsole.txt