[GoLUG] *** Was: Linux Campfire Tales and now is a small Zombie Apocalypse of the process table

[Kyle Terrien]

On 4/5/24 13:19, David Billsbrough wrote:
> My understanding is that parent process runs and creates a child
> process and then at some point in the future termintates and then
> the child process has no one to return its final exit code to return
> to whom spawned it.   ... or something like that!!

Yeah, those are orphans, a similar concept.  Zombies exit before their 
parent processes.  Orphans, on the other hand, outlive their parent 
processes.

When a process is orphaned, it is re-parented to PID 1, which runs a 
special init process.  You can also have orphaned zombies: if a process 
exits, and its parent exits without ever calling wait() on the process, 
then the process gets re-parented to PID 1.  It becomes an orphan and a 
zombie.

For that reason, one of the duties of PID 1 is to call wait() on its 
children to cleanup orphaned zombies.

I can't remember how Void integrates runit (does it bootstrap off of 
Miquel van Smoorenburg's init, is it using suckless sinit, or something 
else unusual?), and I wasn't present at the story.  So, it sounds 
unusual that PID 1 isn't reaping children.

-- 
[*] Kyle Terrien
     Containerizing chaos to get to the root of the problem.
   @ kyle at terren.us
   @ kyleterrien at gmail.com
   W https://terren.us/