Reasons for defunct

[dhina]

Hi all,
What are the likely reasons that a process may become defunct (i.e., Zombie) in a linux envirionment.

P.S:
ps -aux shows "zl" as state of the process.

[scm]

A defunct process is one that has terminated but whose parent has not waited for it and read the exit status. The only space a defunct process occupies is a slot in the process table since that's where the exit status is held, and it'll stay there until its exit status has been read. Killing the parent will get rid of the defunct process since it will then be inherited by init (process id 1) which reaps it immediately. You can use ps -ef to find out the parent process id.

So, to answer your question, the reason for a defunct process is a poorly implemented process that doesn't reap its dead offspring.