Killing zombie process
Zombie process is an inactive computer process, according to wikipedia article, "...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..."
So how do I find out zombie process?
Use top or ps command:
# top
OR
# ps aux | awk '{ print $8 " " $2 }' | grep -w Z
Output:
Z 4104 Z 5320 Z 2945
How do I kill zombie process?
You cannot kill zombies, as they are already dead. But if you have too many zombies then kill parent process or restart service.
You can kill zombie process using PID obtained from any one of the above command. For example kill zombie proces having PID 4104:
# kill -9 4104
Please note that kill -9 does not guarantee to kill a zombie process (see below for more info).
How do I automate zombie process killing?
Write a script and schedule as a cron job.
See also:
What are these zombie processes that show up in ps? I kill them but they don't go away! by David Newall.
You may also be interested in other helpful articles:
- Best Linux / UNIX Posts of 2007: Part ~ II
- How scriptkiddies turns Linux box into a Zombie
- nixCraft FAQ Roundup ~ July, 30, 2007
- Linux and UNIX interactive, process and users monitoring tool
- Lighttpd web server and php eAccelerator cache problem
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My friend is using something as follow (he calls it as linux zombies kill script.. LOL)
for each in `ps jauxww | grep Z | grep -v PID | awk ‘{print $3}’`; do for every in `ps auxw | grep $each | grep cron | awk ‘{print $2}’`; do kill -9 $every; done; done
Hope it will be useful to someone.
help me…
awk: cmd. line:1: .{print
awk: cmd. line:1: ^ syntax error
awk: cmd. line:2: (END OF FILE)
awk: cmd. line:2: syntax error
ERROR: Conflicting format options.
Just copy and paste the code. I have fixed the css code problem.
grepping for the “word” Z won’t show Zombies that are also session leaders (such as Xorg) which show up as Zs
recommend ending with “| grep Z”
You should read the Wikipedia article more closely. There is no point sending a SIGKILL to a zombie process.
$ cat makezombie.c
#include
#include
#include
#include
int main(int argc, char *argv[])
{
pid_t child;
for (;;)
{
child = fork();
if (0 == child)
{
/* Whaddya know, I am the walrus^Wchild. Announce myself and
* exit immediately, making myself a zombie.
*/
fprintf(stdout, “Child PID is %ld\n”, (signed long int)getpid());
exit(0);
}
else if (child > 0)
{
/* I’m the parent. Loop without
* reaping the child.
*/
for (;;)
{
sleep(1);
}
}
else
{
/* fork() failed. Wait and try again. */
perror(”fork”);
sleep(1);
}
}
}
$ cc makezombie.c -o makezombie
$ ls -l makezombie
-rwxr-x— 1 youngman eng 9871 Mar 27 16:52 makezombie
$ ps
PID TTY TIME CMD
1769 pts/2 00:00:00 bash
2348 pts/2 00:00:00 ps
$ ./makezombie &
[1] 2351
$ Child PID is 2352
ps
PID TTY TIME CMD
1769 pts/2 00:00:00 bash
2351 pts/2 00:00:00 makezombie
2352 pts/2 00:00:00 makezombie
2353 pts/2 00:00:00 ps
$ kill -9 2352; echo $?
0
$ ps
PID TTY TIME CMD
1769 pts/2 00:00:00 bash
2351 pts/2 00:00:00 makezombie
2352 pts/2 00:00:00 makezombie
2356 pts/2 00:00:00 ps
$ kill 2351
$ ps
PID TTY TIME CMD
1769 pts/2 00:00:00 bash
2364 pts/2 00:00:00 ps
[1]+ Terminated ./makezombie
$
Plz tell me !
The difference between a thread and a process.
Plz give a detailed explanation.
I hope you will not let me down.
Thank you.
The first script has major issues with it. This is the one that I use
for each in `ps -ef | grep ” | grep -v PID | awk ‘{ print $3 }’`; do for every in `ps -ef | grep $each | grep -v cron | awk ‘{ print $2 }’`; do kill -9 $every; done; done
thanks.
I Got my ans of zombie Process.
The thread is some thing like background job for the process smiler to project count from 1 till 100 and the main purpose of the project is get each number value.
eg in our daily life is some programs can’t do any thing until it’s main job done like some sort of Anti Virus’s when you tried to do another job the program dosen’t respond to any command in the main time i’s in the same process but it take her own mem space
i hope i was any useful for you
#!/usr/bin/bash # # zombie_slayer [OPTIONS] # # -d # Just display the zombie processes and exit # # -h | help # Display help # # Default is to show processes and the ask what to kill (exits if any errors when killing processes) # function Z_Display { echo "" echo "Proc - PID - PPID - State - User" UNIX95= ps -eo comm,pid,ppid,state,user | awk '$4 ~ /Z/ { print $1,$2,$3,$4,$5 }' echo "" } function Z_Kill { read -p "Enter PPID to kill or 'exit' : " SLAY_PPID if [ "$SLAY_PPID" = "exit" ] || [ "$SLAY_PPID" = "" ] then exit fi ps -p $SLAY_PPID | grep -q $SLAY_PPID if [ $? -eq 0 ] then UNIX95= ps -o pid,user,state,comm -p $SLAY_PPID | \ awk '$1 ~ /^[0-9]*$/ { print "The program " $4 " with PID " $1 " is being run by the user " $2 " and is currently in state " $3 }' read -p "Are you sure you want to kill PID $SLAY_PPID ? Y|N : " COMMIT_KILL if [ "$COMMIT_KILL" = "Y" ] || [ "$COMMIT_KILL" = "y" ] then kill -9 $SLAY_PPID if [$? -eq 0] then echo "" read -p "Killed PID $SLAY_PPID. Run again? Y/N : " GO_AGAIN fi else Z_Kill fi else echo "Invalid PID. Try again." echo "" Z_Kill fi } function help { echo "Usage: zombie_slayer [-h | help -d]" echo "-d just display zombie processes and exit" echo "-h | help : This help" exit } if [ "$1" = "-h" ] || [ "$1" = "help" ] then help fi if [ "$1" = "-d" ] then Z_Display else Z_Display Z_Kill fi if [ "$GO_AGAIN" = "Y" ] || [ "$GO_AGAIN" = "y" ] then Z_Display Z_Kill fi echo ""Updated and tested with HP-UX 11i, Solaris 10, Debian, RHEL4 and SUSE 10
#!/usr/bin/bash # # Zombie Slayer # # zombie_slayer [OPTIONS] # # -d # Just diplay the zombie processes and exit # # -h | help # Display help # # Default is to show processes and the ask what to kill # function Z_Display { echo "" echo "PID - PPID - State - User - Proc" UNIX95= ps -eo pid,ppid,state,user,comm | awk 'BEGIN { count=0 } $3 ~ /Z/ { count++; print $1,$2,$3,$4,$5 } END { print "\n" count " Zombie(s) to slay." }' echo "" } function Z_Kill { read -p "Enter PPID to kill or 'exit' : " SLAY_PPID if [ "$SLAY_PPID" = "exit" ] || [ "$SLAY_PPID" = "" ] then exit fi ps -p $SLAY_PPID | grep -q $SLAY_PPID if [ $? -eq 0 ] then UNIX95= ps -o pid,user,state,comm -p $SLAY_PPID | \ awk '$1 ~ /^[0-9]*$/ { print "The program " $4 " with PID " $1 " is being run by the user " $2 " and is currently in state " $3 }' read -p "Are you sure you want to kill PID $SLAY_PPID ? Y|N : " COMMIT_KILL if [ "$COMMIT_KILL" = "Y" ] || [ "$COMMIT_KILL" = "y" ] then kill -9 $SLAY_PPID echo "" read -p "Killed PID $SLAY_PPID. Run again? Y/N : " GO_AGAIN else Z_Kill fi else echo "Invalid PID. Try again." echo "" Z_Kill fi } function help { echo "Usage: zombie_slayer [-h | help -d]" echo "-d just display zombie processes and exit" echo "-h | help : This help" exit } if [ "$1" = "-h" ] || [ "$1" = "help" ] then help fi if [ "$1" = "-d" ] then Z_Display else Z_Display Z_Kill fi if [ "$GO_AGAIN" = "Y" ] || [ "$GO_AGAIN" = "y" ] then Z_Display Z_Kill fi echo ""