[kwlug-disc] tracking down a rampant script

[Insurance Squared Inc.]

I've got a compiled script running on my webserver that runs alot, 
called by various webpages.

Once in a while it seems like the script doesn't stop running; it keeps 
on running and chewing up huge amounts of cpu.  So after a couple of 
days, I end up with 2 or 3 instances of that script running on the 
server continually.  running 'top' will show 0% idle cpu, with all the 
cpu being consumed by that script (with an owner of apache).  Kill the 
pids, everything performs nice again...for a little while.

Meantime, thousands of other executions of the script perform properly - 
they execute for a brief second, spit out their numbers, then die 
gracefully.

How would one diagnose or stop this sporadic rogue behavior?