defunct processes

tajamari · 06-25-2008, 01:47 AM

I had a server running for 3 years, and no major problems were encoutered since. But last week, I noticed that the site was not up and no email notifications (done via php scripts) were sent. Upon verifying, there were defunct applications of HTTPD, SSHD and SENDMAIL

When I thried to reboot the machine, it showed something like this

[root@bigdipper ~]# reboot
Broadcast message from root (pts/1) (Sat Jun 21 16:22:24 2008):

The system is going down for reboot NOW!

init: timeout opening/writing control channel /dev/initctl
[root@bigdipper ~]#
[root@bigdipper ~]#

Is this a hardware related problem or on the php script that sends email in which at an instance the server cant handle the requests?

Any help please?

TedyBear · 06-25-2008, 02:08 AM

try

"reboot -f"

tajamari · 06-25-2008, 11:22 PM

Quote:

Originally Posted by TedyBear

try

"reboot -f"

That's what I did. I want to know the cause of these defunct process. Has anybody encountered same incident?

chrism01 · 06-25-2008, 11:45 PM

You need to start by examining the relevant logfiles. Ideally before the reboot, but you may still find some useful info.

TedyBear · 06-25-2008, 11:55 PM

The following was found on teh man page of init:

Quote:

Diagnostics
If init finds that it is continuously respawning an entry more than 10 times in 2 minutes, it will assume that there is an error in the command string, generate an error message on the system console, and refuse to respawn this entry until either 5 minutes has elapsed or it receives a signal. This prevents it from eating up system resources when someone makes a typographical error in the /etc/inittab file or the program for the entry is removed.

http://linux.die.net/man/5/inittab

Mr. C. · 06-26-2008, 12:24 AM

3 years - nice!

It sounds like you either encountered a bug in init, or some other anomaly.

A defunct process (called a zombie) is a process that has exited, but its parent did not cleanup via wait(2). A bug, or some was some other failure in init (bit flip in init's address space?) could cause init not to cleanup, thereby eventually exhausting various limits. A reboot would be the only cure at that point, since init is the master controlling parent process.