Logged In: YES 
user_id=323786


True -- there are many platform specific issues on the
interaction of forking and threading.

However the _active_limbo_lock is entirely a Python issue (I
think it can deadlock on any platform, unless the platform
releases locks in child process after fork).

After forking, python already resets the GIL, and it should
also reset any other locks that have global impact like
_active_limbo_lock.