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 ~]# ps ax | grep Z 23880 ? Zs 0:00 [checkloadadv.sh] 23926 pts/0 S+ 0:00 grep Z [root@abc ~]# strace -p 23880 attach: ptrace(PTRACE_ATTACH, ...): Operation not permitted [root@abc ~]# pstree | grep checkload init-+-crond---crond-+-checkloadadv.sh [root@abc ~]# bash /usr/bin/checkloadadv.sh System Load is OK : 0.05

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 on reaping the process until I do something like wait or fg? E.g.:

sleep 1 &
sleep 2
ps -ef | grep defunct # I want this to show the sleep 1 process
wait
ps -ef | grep defunct # But now it should be gone

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 Ctrl+Z in the terminal session where the process is running - no effect. I tried killing as root - no effect. Or rather, there is some effect: The process state is no Z(ombie). But it still seems to use ~100% CPU. Can I "kill it harder" somehow? Notes: * The process is interacting with the CUDA driver. Trying to tell my GPU to power down then power up (using nvidia-smi) also has no effect. * Power-cycling the machine works :-(

Consider this example - #include #include #include int main() { pid_t pid = fork(); if (pid > 0) { printf("Child pid is %d\n", (int)pid); sleep(10); system("ps -ef | grep defunct | grep -v grep"); } return 0; } In this example, the child process remains a zombie until the parent process terminates. How did this zombie process get cleaned up without being reaped by any process ? $ ./a.out Child pid is 32029 32029 32028 0 05:40 pts/0 00:00:00 [a.out] $ ps -p 32029 PID TTY TIME CMD

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 alternatives are there pls suggest. For the problem I am facing, below script can catch the status running, sleeping, stopped etc. But for the zombie process, we see two pids for the command pidof zombie. which is getting treated as error and the script does not catch that status. Can anyone suggest how to catch the zombie state of the process. By the way, I have created a zombie process whose status can be seen as zombie for sometime on the shell.

#!/bin/bash

do_start() {
    # List of process names to be monitored for its termination/killing.
    declare -a PROCESS_LIST
    PROCESS_LIST=("process_1" "process_2" "zombie")
    for process in "${PROCESS_LIST[@]}"; do
        echo "checking for $process"
        pid=$(pidof $process)
        echo "its pid is $pid"
        if [ $pid ]; then
            pid_status=head /proc/$pid/status | grep "State:*"
            echo $pid_status
            if [[ "$pid_status" =~ .*"sleeping"*. ]] || [[ "$pid_status" =~ .*"stopped"*. ]] || [[ "$pid_status" =~ .*"running"*. ]]; then
                echo "process:$process with pid $pid is having status $pid_status"
            elif [[ "$pid_status" =~ .*"zombie"*. ]]; then
                echo "process:$process with pid $pid is having status $pid_status"
            fi
        else
            echo "pid not present" > /dev/null
        fi
    done
}

while :
do
    do_start
    sleep 2
done

__OUTPUT__: >checking for process_1 its pid is 12668 State: S (sleeping) process:process_1 with pid 12668 is having status State: S (sleeping) checking for zombie its pid is 12818 12817 ./process_monitor.sh: line 13: [: 12818: unary operator expected > checking for process_1 its pid is 12668 State: R (running) process:process_1 with pid 12668 is having status State: R (running) checking for zombie its pid is 12818 12817 ./process_monitor.sh: line 13: [: 12818: unary operator expected __$ ps ux output__

xolo    12668 95.3  0.0   4164   360 pts/4    R    15:32   0:07 ./process_1  
xolo    12817  0.0  0.0   4160   360 pts/4    S    15:32   0:00 ./zombie  
xolo    12818  0.0  0.0      0     0 pts/4    Z    15:32   0:00 [zombie]

Transmission is intermittently hanging on my NAS. If I send SIGTERM, it doesn't disappear from the process list and a ` label appears next to it. If I send a SIGKILL, it still doesn't disappear and I can't terminate the parent because the parent is init`. The only way I can get rid of the process and restart Transmission is to reboot. I realize the best thing I can do is try and fix Transmission (and I've tried), but I'm a novice at compiling and I wanted to make sure my torrents finished before I start messing around with it.

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 until it finishes and reap it. I have a script like this:

#!/bin/bash
sleep 5 &

tail -f /dev/null

My question is, I don't use wait after sleep 5 & and the parent shell will never terminate because of tail, then why the sleep 5 & will not become a zombie? I see it disappear after finishing in ps, not sure who reaps it?

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" > /tmp/mysqld.init & exec mysqld --init-file=/tmp/mysqld.init But when the fifo file is readout the echo process get a zombie process. How can it be avoided ? **Note** This script is a docker entrypoint script and I don't have a proper zombie handler. Mysqld always takes the pid 1. Something like below. PID PPID USER STAT VSZ %VSZ CPU %CPU COMMAND 1 0 mysql S 383m 19% 0 0% mysqld --init-file=/tmp/mysqld.init 40 0 root R 1532 0% 1 0% top 7 1 root Z 0 0% 0 0% [entrypoint.sh] Probably I can use tini an init system for docker but without it how can it be achieved ? Double fork ?

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](https://www.linuxjournal.com/content/how-kill-zombie-processes-linux) , when I tried to find zombie program by typing PID 3010 does not show up.(see below)

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 1209 ? Ss 0.0 1.3 Aug04 /usr/sbin/apache2 -k start www-data 15531 ? Z 0.0 0.0 Aug15 [apache2] www-data 15539 ? Z 0.0 0.0 Aug15 [apache2] www-data 15540 ? Z 0.0 0.0 Aug15 [apache2] www-data 15541 ? Z 0.0 0.0 Aug15 [apache2] www-data 15542 ? Z 0.0 0.0 Aug15 [apache2] www-data 15543 ? Z 0.0 0.0 Aug15 [apache2] www-data 15544 ? Z 0.0 0.0 Aug15 [apache2] www-data 15545 ? Z 0.0 0.0 Aug15 [apache2] www-data 15546 ? Z 0.0 0.0 Aug15 [apache2] www-data 15547 ? Z 0.0 0.0 Aug15 [apache2] www-data 15548 ? Z 0.0 0.0 Aug15 [apache2] www-data 15549 ? Z 0.0 0.0 Aug15 [apache2] www-data 15550 ? Z 0.0 0.0 Aug15 [apache2] www-data 15551 ? Z 0.0 0.0 Aug15 [apache2] www-data 15552 ? Z 0.0 0.0 Aug15 [apache2] www-data 15553 ? Z 0.0 0.0 Aug15 [apache2] www-data 15554 ? Z 0.0 0.0 Aug15 [apache2] My Apache server has very light use, I can browse the server fine for a while, but then I click a link and it suddenly crashes. I am not able to pinpoint what exactly causes the crash, seems random to me. My server is Debian Buster, and the apache server is using php5 framework (for Dokuwiki). Following packages are installed: apache2 2.4.38-3 apache2-bin 2.4.38-3 apache2-data 2.4.38-3 apache2-utils 2.4.38-3 libapache2-mod-php5.6 5.6.40 php5.6 5.6.40 php5.6-cli 5.6.40 php5.6-common 5.6.40 php5.6-curl 5.6.40 php5.6-json 5.6.40 php5.6-mysql 5.6.40 php5.6-opcache 5.6.40 php5.6-readline 5.6.40 php5.6-sqlite3 5.6.40 php5.6-xml 5.6.40 **How can I troubleshoot this problem?** There is no message in any of my logs (dmesg, syslog, or apache errror log)

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 likes to, so just sending a SIGTERM will be to harsh, I think? I'll use SIGKILL ("-9") last, that's clear. But which to start? SIGHUP? Which signals are just a waste of time? The relevant signals for reference, from man 7 signal Signal Value Action Comment ────────────────────────────────────────────────────────────────────── SIGHUP 1 Term Hangup detected on controlling terminal or death of controlling process SIGINT 2 Term Interrupt from keyboard SIGQUIT 3 Core Quit from keyboard SIGKILL 9 Term Kill signal SIGPIPE 13 Term Broken pipe: write to pipe with no readers SIGTERM 15 Term Termination signal

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 child, there is not supposed to be any effect. Does this mean that the exit code will not be modified by the SIGKILL or will the exit code be modified to indicate that the child exited because it received a SIGKILL?

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+ 0:00 [x86_64-pc-linux] 21838 pts/5 S+ 0:00 grep --colour=auto defunct serenity ~ # gdb -p 11351 GNU gdb (Gentoo 7.10.1 vanilla) 7.10.1 [snip] Attaching to process 11351 warning: process 11351 is a zombie - the process has already terminated ptrace: Operation not permitted. (gdb) [This question](https://stackoverflow.com/questions/19215177/gdb-ptrace-operation-not-permitted) suggests the problem is with proc.sys.kernel.yama.ptrace_scope, or that I might not be root, but that sysctl isn't present on my system, and I _am_ running as root: serenity ~ # sysctl -a | grep ptrace sysctl: reading key "net.ipv6.conf.all.stable_secret" sysctl: reading key "net.ipv6.conf.default.stable_secret" sysctl: reading key "net.ipv6.conf.enp4s0.stable_secret" sysctl: reading key "net.ipv6.conf.lo.stable_secret" serenity ~ # whoami root serenity ~ # For reference, my kernel version is 4.9.16-gentoo.

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 the current session. But top and ps -e are working fine. So it seems that there are two problems the filesystem not responding. This is a production machine running virtual machines, so rebooting isn't an option. The following processes ids aren't working: 16181 16765 5985 7427 7547 The parent of these processes is init ├─collectd(16765)─┬─{collectd}(16776) │ ├─{collectd}(16777) │ ├─{collectd}(16778) │ ├─{collectd}(16779) │ ├─{collectd}(16780) │ └─{collectd}(16781) ├─collectd(28642)───{collectd}(28650) ├─collectd(29868)─┬─{collectd}(29873) │ ├─{collectd}(29874) │ ├─{collectd}(29875) │ └─{collectd}(29876) And one of the qemu processes not working |-qemu-system-x86(16181)-+-{qemu-system-x86}(16232) | |-{qemu-system-x86}(16238) | |-{qemu-system-x86}(16803) | |-{qemu-system-x86}(17990) | |-{qemu-system-x86}(17991) | |-{qemu-system-x86}(17992) | |-{qemu-system-x86}(18062) | |-{qemu-system-x86}(18066) | |-{qemu-system-x86}(18072) | |-{qemu-system-x86}(18073) | |-{qemu-system-x86}(18074) | |-{qemu-system-x86}(18078) | |-{qemu-system-x86}(18079) | |-{qemu-system-x86}(18086) | |-{qemu-system-x86}(18088) | |-{qemu-system-x86}(18092) | |-{qemu-system-x86}(18107) | |-{qemu-system-x86}(18108) | |-{qemu-system-x86}(18111) | |-{qemu-system-x86}(18113) | |-{qemu-system-x86}(18114) | |-{qemu-system-x86}(18119) | |-{qemu-system-x86}(23147) | `-{qemu-system-x86}(27051)

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)?

I'm just playing around with zombie processes on WSL. I wrote a quite simple program: #include #include #include #define CHILD 0 int main(){ int p; p = fork(); if(p == CHILD){ printf("Kind-PID: %u\n", getpid()); exit(1); } else if(p > CHILD){ sleep(30); } else return EXIT_FAILURE; return EXIT_SUCCESS; } While I can see the zombie process on a native Linux using ps, I can't see a zombie process on WSL. Can anyone explain why?

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 check if they crash, and in that case restart the crashed process. Also, process “A” runs a separated thread for RTC sync purposes. “A” is started as /bin/sh -c A B C D etc. I am on an embedded environment and I am using a customized kernel derived from Linux 4.4.57. Now to the the problem: it happens sometimes my process “A” becomes zombie! Some observations I made: - the parent process /bin/sh -c, which started “A” is still alive; - none of the child processes “B”, “C”, etc. are dead; - “A” responds to signals; - if I kill the parent process /bin/sh -c, “A”'s parent becomes init (1) but still, the process remains zombie; - the only way to kill the zombie “A” is to issue a kill -9 «pid-of-A»; - the RTC sync thread is still running!; Now, because of “A” responding to signals and the internal thread still running, this zombie process is driving me crazy. What explains such behavior? Might it be something related to kernel build configuration? **EDIT**: I have looked better at the code and found out that “A” is started as a daemon with the following command: start-stop-daemon -b --start --quiet --pidfile /var/run/A.pid --background --exec /bin/sh -- -c "A B C D > /var/log/log 2>&1" **UPDATE**: I've been able to replicate the same exact behavior by calling pthread_exit(). The problem is that I can't find any reference to phread_exit on the original source. Is there any other way the main thread might stop leaving alive all the others?

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 going to call the wait function. I see bash has a builtin wait function, but when I use it to try to reap one of the zombies, I get the following error. # wait 17517 bash: wait: pid 17517 is not a child of this shell I am root, but that does not seem to make a difference. I have a couple questions 1. Can I reap a zombie process if it is not the child of my shell? 2. If not, is there anything I can do? I am not certain I should kill the parent 3. Should I be worried? It seems the parent has a resource leak and is not garbage collecting or whatever.

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 mount points that are found in FSTAB the command works successfully (e.g. df /home). How do I go about troubleshooting this?

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 shows ps running with a PID 1. What did I do wrong? What is the proper way to use the image? me@host:~/app1$ docker run --rm phusion/baseimage ps aux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1 3.0 0.0 29180 1404 ? Rs 01:27 0:00 ps aux