Why do I always get a Zombie process

[Wang,MinJie]

Hi all
When I ran "ps -el|grep Z" I got the following information :
F S UID ... COMD
1 Z 0 ...

And I can't kill it by "kill -9"
So what is it?
Thank you

[Torsten.]

I'm sure this is related to the online diagnostics - this is pretty normal (at least for older diagnostics releases).

Example:

# ps -ef|grep defunct
...
root 11348 2209 0 08:49:53 ? 0:00

# ps -ef|grep 2209
...
root 2209 1 0 Nov 29 ? 7:25 /usr/sbin/stm/uut/bin/tools/monitor/ia64_corehw
...



You can try to search the web for "ia64_corehw" and "defunct" to get some more information.

[Dennis Handly]

You get zombies because of ill-behaved zombie masters not waiting for their children. If you want to kill the zombie, you need to kill the zombie master.

In your example, it would be helpful to find who is the PPID.

See cautions about zombie masters:
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1169716
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1159219
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1152917
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1145648
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1129236

[Venkatesh BL]

Zombies are created when a process completes its work (exits) before its parent could 'wait' for it. So, in your case you could see the ppid to know which parent process is responsible for this situation.

[Torsten.]

See also this related thread:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=513630

What version of online diagnostics are you running?
(run "cstm" to get this info)

[Kapil Jha]

defunct process is a processes which is finished - but still depends on a "parent" which is still alive.

Only way to kill is kill the parent and they would be gone.If parent is 1 you'll have to reboot.

These threads may help you
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=684634&admit=109447626+1198051860734+28353475

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=765302&admit=109447626+1198051963584+28353475


Hope this help
BR,
Kapil

[Dennis Handly]

>Kapil: if parent is 1 you'll have to reboot.

If parent is 1 these are not zombies but hung processes if kill -9 doesn't work.

[Torsten.]

MinJie,
please come back with some more details about your process(es).

I still assume it is related to the diags.
If, you will get always different "zombies" but the parent stays the same, an example:

#ps -ef|grep defunct
root 13622 2209 0 10:01:18 ? 0:00

#ps -ef|grep defunct
root 13651 2209 0 10:03:18 ? 0:00

[Steven E. Protter]

Shalom Wang,

I have found defunct/Zombie processes almost always result from bugs in application software. Sometimes if kernel limits are being tested this is a factor in the problem.

Zombies won't die from a kill -9

kill -9 says kill the process and its parent. You will find the parent of this process is process 1. If you would be permitted to kill that your whole system would suddenly stop.

Reboot will clear the zombie. Then the offending application will need to be fixed.

Shmuel