How to kill a zombie process

When you have a zombie process that does not respond to kill -9, then we can try a few more options.

Option 1: sending a signal to the parent process

Use the kill command and send the SIGCHLD signal. This might trigger the required wait() function and return things in a normal state. kill -SIGCHLD PID-OF-PARENT-PROCESS

Option 2: kill the parent process

If the first option does not work, then try stopping the parent process. Sometimes this might properly close the child process as well.

Option 3: reboot

Both options not working? Then a reboot will, as this will stop everything and start the system with a fresh process table.