Questions tagged [zombie-process]

A “zombie process” is an entry in the process table corresponding to a dead process. The entry will be remove when the process's parent checks its child's return status.

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Is it possible to defer reaping of background processes in bash?

If I just run sleep 1 & in bash, the sleep process will get reaped almost instantly after it dies. This happens whether job control is enabled or disabled. Is there a way I can make bash hold off ...
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How can I kill a process in Linux when kill -9 fails?

I have a process (actually a pair of them) numbered 1234 which uses my NVIDIA GPUs. I want to kill it. I tried kill 1234; I tried kill -9 1234 I tried kill -KILL 1234 - no effect. Tried Ctrl+C and ...
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Why or how does killing the parent process clean the zombie child processes in linux?

Consider this example - #include<stdio.h> #include<stdlib.h> #include<unistd.h> int main() { pid_t pid = fork(); if (pid > 0) { printf("Child pid is %d\n", (...
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handling zombie process status

I am new to scripting. I am writing a process status monitor script that should catch when a process gets killed, zombied or sleeping etc. I am not sure this is really a good script, if any better ...
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zombie process reap without "wait"

I know if a subprocess does not get reaped properly, it will become a zombie and you can see it by ps command. Also the "wait [pid]" command will wait for subshell running on the background ...
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Unable to kill a process that shows up on ps aux

I am unable to close WinZip. My command is shown below. Note that I don't think it is what is called a zombie program because according to this website, when I tried to find zombie program by typing ...
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apache2 crashes suddenly and leaves zombie processes

I am experiencing recurring problem with my apache server, where after few hours/days of light usage, the apache process suddenly crashes and leaves zombie processes. In ps, I then see this: root ...
Martin Vegter's user avatar
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Does Linux sends `SIGCHLD` to `init` when it inherits orphaned zombie processes?

Does Linux sends SIGCHLD to init (PID 1 process) when it inherits orphaned zombie processes (processes that have not been reaped by its original parent)?
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WSL - Different behavior for zombie processes

I'm just playing around with zombie processes on WSL. I wrote a quite simple program: #include <stdio.h> #include <stdlib.h> #include <unistd.h> #define CHILD 0 int main(){ ...
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How to avoid zombie process while working with named pipe?

We normally do the writing job to a FIFO file in background using a control operator &. Something like below. if [ ! -p "/tmp/mysqld.init" ]; then mkfifo /tmp/mysqld.init fi echo "something"...
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Strange zombie process responds to signals?

I have a strange situation. I have a c-written program “A” which takes as argument the name of other executables, e.g. “B”, “C”, “D” etc.. The main job of “A” is to fork and start “B”, “C” etc, then ...
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How can I reap a zombie process that is not a child of my shell?

I have a server with a ton of zombie processes. Almost a thousand. If possible, I would like to reap these processes because it doesn't seem like the parent (one parent is causing all 1000 zombies) is ...
Timothy Pulliam's user avatar
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df (with options) leaves zombie process

OS = CentOS 7.3 If I try to run the 'df' command on this server with an option (e.g. -h -l) it hangs and leaves a zombie process. I cannot Ctrl+z out back to a prompt. If I run 'df' against specific ...
Heisenberg's user avatar
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How should one invoke docker to take care of the PID 1 problem with zombie processes?

The phusion/baseimage boasts of taking care of the pid 1 problem with a light weight init process. How can one use the phusion/baseimage properly? I tried to invoke the image with the command ps aux ...
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ptrace: Operation not permitted when attaching to a zombie process

I have a reproducible situation where a compiler instance goes into a zombie state when I rebuild a package, but gdb won't permit me to attach: serenity ~ # ps ax | grep defunct 11351 pts/1 Z+ ...
Michael Mol's user avatar
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Background, zombie, daemon and without ctty - are these concepts connected?

How these process concepts are related together - background, zombie, daemon and without controlling terminal? I feel that they are somehow close, especially through the concept of controlling ...
anatoly techtonik's user avatar
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Why is a zombie waiting for its child?

I'm digging through different sources, but can't find a good description of the anatomy of child reaping. This is a simple case of what I would like to understand. $ cat <( sleep 100 & wait ) &...
user avatar
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4 answers
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<defunct> processes remain behind

I have an embedded system that was going non-responsive after running for several hours. After investigating I found that the system kept growing a list of <defunct> processes. Running ps axl ...
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What happends when sending SIGKILL to a Zombie Process in Linux?

In Linux, when a child process terminates and it's parent has not yet waited on it, it becomes a zombie process. The child's exit code is stored in the pid descriptor. If a SIGKILL is sent to the ...
user137481's user avatar
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Can a zombie have orphans? Will the orphan children be disturbed by reaping the zombie?

As I understand it, a zombie process has died but still exists as a placeholder in the process table until its parent (or init if the zombie is itself an orphan) checks its exit status. And my ...
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Why does this pipe not end when the las process dies (zombie)?

I have a script run and monitored by svscan/supervise. When the last luces-hf/run: #!/bin/bash set -v export http_proxy=[redacted] curl -N -s https://[redacted] |\ grep --line-buffered "event" | ...
marianov's user avatar
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Killing a comet zombie

I have a zombie process that is changing its PID, which is increasing. Is it possible to kill a process with PID greater than N?
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Is there a need to get rid of a zombie process? [duplicate]

I read somewhere (forgot where) that a zombie process continues to consume the process table entry (concretely the process identifier or PID), and causes a resource leak. Is it correct that a zombie ...
Tim's user avatar
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Why cannot we kill a zombie? [duplicate]

I am editing this question since it was marked duplicate as another question about how to kill a zombie process. I am not looking for an answer to how to kill a zombie process. I do not have zombies ...
Sreeraj's user avatar
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How does linux handles zombie process

Zombie processes are created in Unix/Linux systems. We can remove them via the kill command. But is there any in-built clean-up mechanism in Linux to handle zombie processes?
Atur's user avatar
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How to kill - softly? [duplicate]

If I want to kill a process as careful and politely as possible, which signals should I use in a kill command, in which order? I would like to give the programm any kind of time to clean up, if it ...
Volker Siegel's user avatar
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sslserver using 100% cpu

I've a qmail setup with sslserver being used to secure the pop connections. Normally it runs very well, however some instances of sslserver start taking 100% cpu and its child process qmail-pop3d ...
amolkul's user avatar
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How are zombie processes handled when the parent dies?

Which technique does the Unix system use to remove zombie processes whose parent has terminated?
user3665919's user avatar
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1 answer
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Does this dispatcher produce zombie process?

I have such a dispatcher shell script. while read line do java TestProg $line & done < $tasklist On the zombie process Wikipedia page, it says if a parent fails to call wait, the ...
Marcus Thornton's user avatar
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1 answer
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Why Process/program becomes zombie?

If script is running fine from command line then, why the same script becomes zombie state after running through cron and How you will troubleshoot the same ? Here following real example : [root@abc ...
Rahul Patil's user avatar
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Are zombie processes something I should be concerned about? [duplicate]

I run a server. Should I be concerned about zombie processes? Do they consume any system resources (RAM, process table entry, etc.) that I should be concerned about?
strugee's user avatar
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4 answers
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How to kill a process which can't be killed without rebooting?

There are 5 processes which can't be killed by kill -9 $PID and executing cat /proc/$PID/cmdline will hang the current session. Maybe they're zombie processes. Executing ps -ef or htop will also hang ...
Sam Stoelinga's user avatar
2 votes
2 answers
2k views

Is there any impact of reaping zombie processes?

I will execute following command for reaping zombie /usr/bin/preap $(ps -ef | grep defunct | grep -v grep | awk '{ print $2 }' | xargs) Is there any service impact of this approach ?
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Is there an upper limit to the number of zombie processes you can have?

I used to work with an HP-UX system and the old admin told me there is an upper limit on the number of zombie processes you can have on the system, I believe 1024. Is this a hard fact ceiling? I ...
ProfessionalAmateur's user avatar
6 votes
6 answers
15k views

Is there a way to identify which process turns into Zombie process

One of the ubuntu server has 82 zombie processes. All processes shows '[sh] defunct' as process command. Is there a way to find out which process is becoming a zombie process? I tried checking the /...
user379997's user avatar
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What is a zombie process? [closed]

Could you tell me the meaning of a "zombie process" and give an example.
fronthem's user avatar
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Removing zombie process from the process table

Can somebody please explain when parent process receives the exit status of a dead child process via wait, who actually reallocates the memory of the child process and removes it from the process ...
user avatar
28 votes
3 answers
67k views

How can I kill a <defunct> process whose parent is init?

Transmission is intermittently hanging on my NAS. If I send SIGTERM, it doesn't disappear from the process list and a <defunct> label appears next to it. If I send a SIGKILL, it still doesn't ...
Andy E's user avatar
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