> if a
> thread ends up being created/destroyed, I think we can get a deadlock
> when trying to acquire the head lock. I think it should be turned into
> an open call if possible.

How would you do that in a simple way?

> Also, as noted by Stefan, shouldn't we also iterate over other interpreters?

The problem is that, AFAIK, we don't know which thread states of the other interpreters should be kept alive.