Date: Thu, 13 Jun 2002 13:24:57 +0300 (EEST) From: Layder <layder@ukr.net> To: freebsd-stable@freebsd.org Subject: Re: Zombie processes (fwd) Message-ID: <20020613131834.S4010-100000@cyanide.pro>
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---------- Forwarded message ----------
Date: Wed, 12 Jun 2002 15:29:30 -0500
From: Jack L. Stone <jackstone@sage-one.net>
To: Layder <layder@ukr.net>, freebsd-stable@FreeBSD.ORG
Subject: Re: Zombie processes
At 11:00 PM 6.12.2002 +0300, Layder wrote:
>Processes in my box never gone. They become zombies and their
>quantity increased with time and than locks the system talking that
>cannot fork process. What can I do?
>My system is Celeron 500 with 64 MB RAM
>
Here was the advice I received a couple of weeks ago:
$ ps alx | grep Z
UID PID PPID CPU PRI NI VSZ RSS WCHAN STAT TT TIME COMMAND
1004 82075 6901 295 96 0 0 0 - Z+ p5 0:00.00 (sh)
See the Z under STAT? That show that the process is a zombie.
and what does it mean...????
It means that the process has died, but hasn't been buried yet. The
trouble with zombies is that you can't kill them, because they're
already dead :-) First the parent process (6901 in this example) must
wait for it and collect its status.
You have two choices here:
1. Ignore it, it's not holding on to too many resources.
2. Kill the parent. That may or may not be a good idea. For
example, in this case,
$ ps lp6901
UID PID PPID CPU PRI NI VSZ RSS WCHAN STAT TT TIME COMMAND
1004 6901 6620 127 20 0 848 102 opause S+ p5 5:42.68
observe dates
This is a process I have on my machine which shows the dates
around the world every 2 seconds. Sure, I can kill it and restart
it, but is there any point? In this case, if I go back and look
for that zombie, I'll find it's already gone: I've just caught a
zombie in the stage before being buried. In other cases, and
especially if the program is causing lots of zombies, you may want
to stop it.
Best regards,
Jack L. Stone,
Administrator
SageOne Net
http://www.sage-one.net
jackstone@sage-one.net
-----------------------------------------
That's what ps -jfax | grep Z shows:
root 62 1 62 c0a5e840 0 Z ?? 0:00.00 (ppp)
root 177 1 177 c0a89d80 0 Z ?? 0:00.00 (squid)
root 230 1 226 c0a8df80 0 Z ?? 0:00.00 (gzip)
root 276 1 272 c0a89080 0 Z ?? 0:00.00 (gzip)
root 322 1 318 c0a89e00 0 Z ?? 0:00.00 (gzip)
root 372 1 368 c0a914c0 0 Z ?? 0:00.00 (gzip)
root 435 1 435 c0a5ee40 0 Z ?? 0:00.00 (ppp)
root 175 1 7 c0a43f80 0 Z con- 0:00.00 (squid)
after i gzip something, gzip becomes a zombie and never dies completely
init is the parent of these processes so i can't kill it.
I'll have a bunch of zombies just within a few hours after system startup.
Can this be a hardware problem? This happens only on one this machine,
two others work just fine.
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