Quote:
3. how do I query 'zombie' processes?
Depending on the ps/OS zombies are either listed as <defunct> (on most Unices),
or simply as zombie.
You cannot query them because these are already dead (finished) processes
whose parent procs already exited without caring for their exit status.
The occurrence of zombies is most of the times an indication of badly
programmed applications.
You should at least file a bug report with their developers,
but even better not use these programs anymore.
Because zombies are already dead
they take up no resources only a slot in the process table,
which indeed can become a massive problem if a berserk application
is producing lots of them so that the total number of slots in the system's
process table gets filled up.
When this finally happens your only choice is a system reboot.
That's why zombies are sign of bad programming.