Index: Lib/threading.py
===================================================================
--- Lib/threading.py	(revision 65077)
+++ Lib/threading.py	(working copy)
@@ -814,7 +814,11 @@
 # and make it available for the interpreter
 # (Py_Main) as threading._shutdown.
 
-_shutdown = _MainThread()._exitfunc
+_shutdown = None
+def __init_threading():
+    global _shutdown
+    _shutdown = _MainThread()._exitfunc
+__init_threading()
 
 # get thread-local implementation, either from the thread
 # module, or from the python fallback
@@ -839,11 +843,8 @@
     new_active = {}
     current = current_thread()
     with _active_limbo_lock:
-        for ident, thread in _active.iteritems():
-            if thread is current:
-                # There is only one active thread.
-                new_active[ident] = thread
-            else:
+        for thread in _active.itervalues():
+            if thread is not current:
                 # All the others are already stopped.
                 # We don't call _Thread__stop() because it tries to acquire
                 # thread._Thread__block which could also have been held while
@@ -852,10 +853,10 @@
 
         _limbo.clear()
         _active.clear()
-        _active.update(new_active)
-        assert len(_active) == 1
 
+    __init_threading()
 
+
 # Self-test code
 
 def _test():