zombie process at bootup

llesher@readingeagle.com · 12-06-2010, 03:15 PM

I got this OS, recently updated:
Red Hat Enterprise Linux AS release 4 (Nahant Update 8)
Kernel 2.6.9-89.33.1.ELsmp on an i686

I get a zombie process immediately after boot; rebooting does not clear the process, guess it gets re-created.
As you can see, it's an Xsession. Only thing using X is the console.

These are the details.
ps -eo uid,pid,tid,spid,stat,comm,tty | grep Z
UID PID TID SPID STAT COMMAND TT
0 5073 5073 5073 Z Xsession <defunc ?

ps -ef --forest
root 4299 1 0 14:49 ? 00:00:00 /usr/bin/gdm-binary -nodaemon
root 4933 4299 0 14:49 ? 00:00:00 \_ /usr/bin/gdm-binary -nodaemon
root 4939 4933 0 14:49 ? 00:00:12 \_ /usr/X11R6/bin/X :0 -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7
root 5054 4933 0 14:50 ? 00:00:00 \_ /usr/bin/gnome-session
root 5073 5054 0 14:50 ? 00:00:00 \_ [Xsession] <defunct>
root 5088 5054 0 14:50 ? 00:00:00 \_ /usr/bin/ssh-agent /bin/sh -c exec -l /bin/bash -c "/usr/bin/dbus-launch

Anyone got any ideas for a solution?

MensaWater · 12-06-2010, 03:38 PM

Rebooting clears ALL processes so this is being created again after a boot.

A zombie process is not in and of itself an issue. What problem are you having that makes you think this zombie is causing it?

It isn't unusual to see some processes become zombies. (For example any time one launches the man command on HP-UX there is a process listed as a zombie while the read is going on - it goes away when the man session is exited.)

What IS a sign of a problem is if you see multiple zombie processes that continue to grow in number. This is usually a sign that something is trying to fire off but is having issues so is going defunct then trying a new process. The issue there is NOT to find a way to get rid of the zombie but to find out what is creating it.

By the way many zombies will go away when their PPID does - they become defunct waiting on input that they'll never get but when the parent process goes away it can often take its children with it.

llesher@readingeagle.com · 12-07-2010, 02:38 PM

Thanks for the quick response, it gave me some ideas to look into. To answer mensawater's question about what problem is causes: For one thing, the gui freezes up, eventually. Further investigation revealed if I logoff level-5 console and leave it at the level-5 login screen & telnet in, I see no (zero) zombie processes. As soon as I log in the console and get the gnome desktop, I get a zombie process. That sort of indicates the console startup process (X & gnome) is causing the zombie. The zombie processes do increase but only by a few. Since the console logs in only once, I don't know what is causing the zombie's to increase. I've been monitoring this server since 2006 and have never seen even 1 zombie process before, so whatever is causing the zombie is recent. If frozen gui is only thing I need to worry about, I can ignore it. Guess the problem with that is, I don't KNOW.