zombie-process

I was having a discussion with a teammate about locking in .NET. He's a really bright guy with an extensive background in both lower-level and higher-level programming, but his experience with lower level programming far exceeds mine. Anyway, He argued that .NET locking should be avoided on critical systems expected to be under heavy-load if at all possible in order to avoid the admittedly small possibility of a "zombie thread" crashing a system. I routinely use locking and I didn't know what a "zombie thread" was, so I asked. The impression I got from his explanation is that a zombie thread

I can find questions about zombies but none that directly addresses what they are and why and how they occur. There are a couple that address what zombie processes are in the context of answering a specific question but don't address the cause. There are also questions regarding zombie processes and questions about Objective-C/Cocoa-related zombie objects. What are the differences or how are these related? Is an "EXEC_BAD_ACCESS" on Mac/iPhone (or similar error on other platforms) synonymous with a zombie? How can one prevent zombies and are there any best practices that will help avoid them?

I launched my program in the foreground (a daemon program), and then I killed it with kill -9 , but I get a zombie remaining and I m not able to kill it with kill -9 . How to kill a zombie process? If the zombie is a dead process (already killed), how I remove it from the output of ps aux ? root@OpenWrt:~# anyprogramd & root@OpenWrt:~# ps aux | grep anyprogram 1163 root 2552 S anyprogramd 1167 root 2552 S anyprogramd 1169 root 2552 S anyprogramd 1170 root 2552 S anyprogramd 10101 root 944 S grep anyprogram root@OpenWrt:~# pidof anyprogramd 1170 1169 1167 1163 root@OpenWrt:~# kill -9 1170 1169

Is there a way to ensure all created subprocess are dead at exit time of a Python program? By subprocess I mean those created with subprocess.Popen(). If not, should I iterate over all of the issuing kills and then kills -9? anything cleaner? You can use atexit for this, and register any clean up tasks to be run when your program exits. atexit.register(func[, *args[, **kargs]]) In your cleanup process, you can also implement your own wait, and kill it when a your desired timeout occurs. >>> import atexit >>> import sys >>> import time >>> >>> >>> >>> def cleanup(): ... timeout_sec = 5 ... for