Dead process

[juno3]

There are so many defunct processes generated in our system , how to eliminate these process ?

[Alex Lavrov]

Well, kill -9 not always works for defunct processes (zombies), but try it anyway couple of times. You can just sit and wait until they disappear or reboot the system.
Anyway, u must check your system, why there is so many zombies, may be it's caused by some bug in your system or someone just works wrong with it and causes so many defuncts, normally, there must be no defunct proccesess ...

good luck.

[Printaporn_1]

you need to reboot !

[Alex Lavrov]

There is alway reboot option, but maybe after couple of hours (even days) there will be a bunch of defunct processes again.
I suggest to find out the source of these processes, and then reboot.

[Bill Hassell]

man glossary

A defunct process is also known as a zombie because it is already dead but the parent failed to handle the chile process correctly. Tow possibilities:

1. Bad programming techniques in starting processes,

2. use of kill -9 indiscriminately

Item 2 is very common to new sysadmins that were told to kill everything with -9 in some Unix-101 class. Nothing could be worse for the stability of the system! kill -9 pulls out the rug from underneath the program, giving the program no chance to handle ope files, unposted buffers, child processes, etc. Never use kill -9! Use kill -15 (or kill with no option which is kill -15 or SIGTERM). If kill -15 doesn't terminate the process, you can then use kill -9 but you'll need to find the reason that the program is ignoring normal kill signals.

[Michael Steele_2]

You can get more information about the process with lsof.

lsof -p pid

Often times a defunct, or zombie, process will be waiting on some I/O, like with an open file. See if another process also has your defunct process's open file.

Also is you pid using shared memory?

ipcs

[Adam J Markiewicz]

Hi

Dead process is most probabilly the fault of the parent, as the parent is oblidget to confirm the childs death.

What can you do is: check the processes parent. If it's not '1' (init) you have a responsible for the whole situation. You can that try to kill it (do not use SIGKILL, try with SIGTERM at the begining). THe processes of the dead parent are 'adopted' by init process. If it adopts zombies - it can remove them.

However if it doesn't help, or if the parent of the zombies is already '1' then you can only reboot.

Good luck
Adam