Defunct Processes

[WSS]

Hi all,

What is the best way to handle defunct/zombie processes?? Not sure what to do with these, but there seems to be quite a few of these on my system.. See below

root@udox305# ps -fe | grep defunct
root 15250 593 0 17:05:27 ttyp5 0:00 grep defunct
wsst1opr 25168 25138 33 Aug 9 ? 0:00
wsst1opr 25154 25137 13 Aug 9 ? 0:00
wsst1opr 25167 25139 36 Aug 9 ? 0:00
wsst1opr 25161 25140 46 Aug 9 ? 0:01
wsst1opr 25153 25136 0 Aug 9 ? 0:00
root 12706 2968 1 17:04:37 ? 0:00
wsst1opr 25209 25142 10 Aug 9 ? 0:00
wsst1opr 25200 25141 25 Aug 9 ? 0:00
wsst1opr 25210 25144 28 Aug 9 ? 0:00
wsst1opr 25188 25143 88 Aug 9 ? 0:00
root 15109 1546 58 Aug 3 ? 0:00

Any help would be much appreciated
Thanks in advance...
Trev

[A. Clay Stephenson · Accepted solution]

These are zombies and there is no way to kill them (because they are already dead) but they do no harm and consume no resources other than a slot in the process table. The only harm that could result is that if you had so many that the system could no longer fork processes because the process table is full. The first thing I would do is question user 'wsst1opr' and find out what he is doing and how he normally exits a program.

[Pete Randall]

The only way to get rid of them, other than re-booting, is to kill the parent process. Try it and see.


Pete

[Jeff Schussele]

Hi Trev,


Usually killing the parent (PPID) will get them.
The init process (PID 1) will attempt to reap them on a scheduled basis, BUT if they are in kernel space they can't be killed by anything.
As long as they're not using a significant amount of resources or growing then I wouldn't worry about it.
IF they are then a reboot is your only option.

Rgds,
Jeff

[Jonathan Fife]

I noticed that these all still have parent pids. Can you do a ps -ef | grep on them and see what process it is?

In any event, killing the parent (if you determine it is safe to do so) should make the parent pid on these 1, and init will typically clean them up.

[WSS]

Cheers for your comments everyone!!

Regards