If you think the watchdog is running OK, and want to test that it really is capable of recovering a crashed system, then you can do one better than Shawn's answer by using the "magic sysrq" to crash the system with a kernel panic. Syncing your file system first is a good idea, so do something like this as root:

sync; sleep 2; sync; echo c > /proc/sysrq-trigger

That should cause a kernel panic if the sysrq is enabled. Then if you wait around 60 seconds (typical time-out for the watchdog module) you should see the machine reboot. Please note this will only work with hardware watchdogs and not the 'softdog' module.

If you think the watchdog is running OK, and want to test that it really is capable of recovering a crashed system, then you can do one better than Shawn's answer by using the "magic sysrq" to crash the system with a kernel panic. Syncing your file system first is a good idea, so do something like this as root:

sync; sleep 2; sync; echo c > /proc/sysrq-trigger

That should cause a kernel panic if the sysrq is enabled. Then if you wait around 60 seconds (typical time-out for the watchdog module) you should see the machine reboot. Please note this will only work with hardware watchdogs and not the 'softdog' module.