Why does this hang the system up

[Able98]

Parallel(n_jobs=-1)(delayed(attempt)(w, pw) for pw in pwds)

What is Parallel?  What's delayed?
delayed looks like a decorator, but what does it do?

From that line, my guess is that you're creating a single spare process, which is passed a generator of attempted passwords.  Although hopefully that's not the case, since attempt uses global variables and writes to sys.stdout.

As I understand it, the Parallel does parallel processing and is part of the joblib library. I had hoped those here would know more than I.

If I understand you correctly, I will replace sys.stdout stuff with "print" and rename the attempt procedure.

My main suspect is the for loop which I would like to rewrite and have the attempt procedure set a flag for it to stop and exit. I do not see where the "raise PasswordFoundException call is needed at all and as I see it causing the problem. Please suggest a way to rewrite the for loop.