This message appears when I login to my machine...

There is 1 zombie process.
  • What is it telling me?
  • Is this anything I should worry about?
  • If yes, then what should I do, and how?
  • 19
    Do you have a double-barrel shotgun nearby? – EEAA May 18 '12 at 0:21

There's nothing to worry about :


On Unix operating systems, a zombie process or defunct process is a process that has completed execution but still has an entry in the process table, allowing the process that started it to read its exit status. In the term's colorful metaphor, the child process has died but has not yet been reaped.

When a process ends, all of the memory and resources associated with it are deallocated so they can be used by other processes. However, the process's entry in the process table remains. The parent is sent a SIGCHLD signal indicating that a child has died; the handler for this signal will typically execute the wait system call, which reads the exit status and removes the zombie. The zombie's process ID and entry in the process table can then be reused. However, if a parent ignores the SIGCHLD, the zombie will be left in the process table. In some situations this may be desirable, for example if the parent creates another child process it ensures that it will not be allocated the same process ID.

Source : http://wiki.answers.com/Q/What_is_Zombie_Process_and_Orphan_Process

  • Thanks Marc good description; now how would I find it, work out whether to keep it, and if not, thence remove it (and the message). – John Mee May 18 '12 at 1:04
  • Usaly they will go off by theirself, if this is really irritating you, you could reboot or find the parent process PID and kill it, but depends on what is leaving zombie behind, that could be problematic to kill that particular process. – Marc-Andre R. May 18 '12 at 1:48
  • 2
    Dont forget to accept my answer if this is the real answer to your question ;) thanks! – Marc-Andre R. May 20 '12 at 20:40
  • 10
    Sorry, you answered only the first part of his question. It's still unclear if one should worry about it and what to do about it. – user142619 Oct 25 '12 at 3:39

As explained in the accepted answer, you have a process that has completed execution but is still in process table: https://serverfault.com/a/390216/48449

This shouldn't cause harm if it's only one process, but still shouldn't happen. If there are too many and you don't reboot or restart the causing parent process that produces those, you could reach your maximum number of allowed processes and cause serious issues.

To find out if worry is appropriate and which other process the zombie belongs to, this works for me:

ps -elf --forest | grep -C5 '<[d]efunct>'

Increase the number of context lines if necessary to find out about the parent process, ideally fix that process to make it "reap" its ended subprocesses.

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