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Old 06-09-2017, 02:15 PM   #1
ttitoo96
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Exclamation Zombie process on Slackware 13.0 [sshd <defunct>]


Hi and thanks for reading.
I have a linux proxy with Slackware 13.0 kernel 2.6.29.6-smp, OpenSSH_5.2p1, OpenSSL 0.9.8k 25 Mar 2009.
When i connect from putty or another terminal via ssh(it doesn't matter) and close the session (with logout or exit command), automatically a zombie process appears. The strange thing is that i have another server with very different harwdware but the same OS and software and it doesn't have this problem.

This is what i see:

root@host:~# ps fax | grep Z | grep -v grep
5037 ? Z 0:00 | \_ [sshd] <defunct>
8181 ? Z 0:00 | \_ [sshd] <defunct>
8651 ? Z 0:00 | \_ [sshd] <defunct>
9358 ? Z 0:00 | \_ [sshd] <defunct>
9469 ? Z 0:00 | \_ [sshd] <defunct>
10074 ? Z 0:00 | \_ [sshd] <defunct>
10519 ? Z 0:00 \_ [sshd] <defunct>

Feel free to ask me for any information.
Thanks!
 
Old 06-10-2017, 02:03 AM   #2
AwesomeMachine
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Hi ttitoo96.

Welcome to LQ!

You can kill the zombies if it makes you feel better. One thing you can try is deleting everything in /tmp and rebooting. I'm not exactly sure why that works, but it does.
 
Old 06-10-2017, 03:59 AM   #3
pan64
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obviously it is a configuration issue, most probably the sshd config is not ok
 
Old 06-11-2017, 02:32 PM   #4
AwesomeMachine
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If it is configuration issue it is quite common.
 
Old 06-12-2017, 06:25 AM   #5
ttitoo96
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Thank you all for your replies.
My /etc/ssh/ssh_config file is by default. No changes has been made.
Here is my /etc/ssh/sshd_config file

root@surfer:/etc/ssh# grep -v "^#" sshd_config | grep .
Port 32460
Protocol 2
PermitRootLogin no
PermitEmptyPasswords no
Subsystem sftp /usr/libexec/sftp-server
 
Old 06-12-2017, 04:05 PM   #6
MadeInGermany
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AFAIR there was such a problem with openssh 5.2.
Might also be a problem with udev or with a "network manager", see this bug.
 
Old 06-13-2017, 09:00 AM   #7
ttitoo96
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Something else?

Quote:
Originally Posted by MadeInGermany View Post
AFAIR there was such a problem with openssh 5.2.
Might also be a problem with udev or with a "network manager", see this bug.
I've read the whole post. I am not an expert, but from reading about this bug i understood that was a problem with the "Sigmask". So i checked that:

cat /proc/`pidof sshd| awk '{print $1}'`/status | grep Sig
SigQ: 0/26543
SigPnd: 0000000000000000
SigBlk: 0000000000000000 # This is right
SigIgn: 0000000000001000
SigCgt: 0000000000010000


I don't think my problem is related to this bug.
Is there something else that i can test?
Thanks so much.
 
Old 06-13-2017, 09:30 AM   #8
pan64
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who is the parent?
do you have anything in ~/.bash_logout (or something similar?)
 
Old 06-13-2017, 11:31 AM   #9
MadeInGermany
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Lightbulb ptree script - show a partial process tree

Do the defunct processes have child processes?
Using the attached ptree script you can do
Code:
ptree `pgrep -ox sshd`
Attached Files
File Type: txt ptree.txt (792 Bytes, 7 views)
 
Old 06-13-2017, 02:33 PM   #10
ttitoo96
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Quote:
Originally Posted by MadeInGermany View Post
Do the defunct processes have child processes?
Using the attached ptree script you can do
Code:
ptree `pgrep -ox sshd`
The defunct processes does not have child processes.
 
  


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