> To me, it doesn't seem dangerous to backport that, but I would love to hear what Eryk and others think :)

In my experience, any change is dangerous :-)

The initial bug doesn't contain any reproducer. I'm talking about:

> If one of the processes in that list is gone, then (...) "The handle is invalid" (...) will prevent you from creating any new processes with Popen after that

It's the first time that I see such bug report. It seems like subprocess works for most people :-) Can you elobrate how to reproduce this issue to justify a backport?