Understanding and Eliminating Zombie Processes in Linux

In Linux systems, zombie processes are a special type of process that has terminated but still remains in the system. Zombie processes do not consume many resources individually, but having too many of them can lead to system resource exhaustion or other issues. This article introduces how to correctly terminate zombie processes.

1. Linux Zombie Processes

When a child process completes its task but its parent process fails to timely check its status, the child process becomes a zombie process. The child process has finished its task but is waiting for its parent process to acknowledge it. The zombie process will be retained until the parent process checks and confirms its completion, otherwise, it remains as a zombie process, lingering in the system.

To check if there are zombie processes in the system, simply run the top command, which displays all running processes along with any zombie processes present in the system (if any).

‘top’ Command Result

From the above image, you can see the PID of processes in Linux, and in the top right corner, it shows that there are no zombie processes in this system.

Are Zombie Processes Harmful to the System?