how to kill a process that is "defunct"?

[Smoot Carl-Mitchell]

On Sun, 2010-11-21 at 13:29 -0500, Hal Burgiss wrote:

> 
> The Z is in the S column means its a zombie, which I believe is
> unkillable using kill on that specific rocess. You'd have to kill, or
> restart the parent process, to get rid of it. 

A Zombie process is a process which has exited, but has not yet been
reaped by its parent. Zombies do not take up any resources except a
process slot in the process table.  This usually indicates a bad design
in the parent process.  Parent processes which fork a child need to
handle the process reaping when the child exits.

Note if the parent process dies or exits before the child, the child's
parent becomes the init process (process 1).  Running

ps -ejH

is useful for showing the process hierarchy when trying to find out why
a process became a zombie.

Killing the parent process might work only because the child's parent
then becomes the init process which correctly waits on all its children.

-- 
Smoot Carl-Mitchell
System/Network Architect
voice: +1 480 922-7313
cell: +1 602 421-9005
smoot at tic.com