Index: Python/ceval.c
===================================================================
--- Python/ceval.c	(revision 60023)
+++ Python/ceval.c	(working copy)
@@ -214,6 +214,7 @@
 
 static PyThread_type_lock interpreter_lock = 0; /* This is the GIL */
 static long main_thread = 0;
+static int stay_forever = 0;
 
 int
 PyEval_ThreadsInitialized(void)
@@ -234,23 +235,34 @@
 void
 PyEval_AcquireLock(void)
 {
+	if (stay_forever && main_thread == PyThread_get_thread_ident())
+		return;
 	PyThread_acquire_lock(interpreter_lock, 1);
 }
 
 void
 PyEval_ReleaseLock(void)
 {
+	if (stay_forever && main_thread == PyThread_get_thread_ident())
+		return;
 	PyThread_release_lock(interpreter_lock);
 }
 
 void
+PyEval_StayForever(void)
+{
+	assert(main_thread == PyThread_get_thread_ident());
+	stay_forever = 1;
+}
+
+void
 PyEval_AcquireThread(PyThreadState *tstate)
 {
 	if (tstate == NULL)
 		Py_FatalError("PyEval_AcquireThread: NULL new thread state");
 	/* Check someone has called PyEval_InitThreads() to create the lock */
 	assert(interpreter_lock);
-	PyThread_acquire_lock(interpreter_lock, 1);
+	PyEval_AcquireLock();
 	if (PyThreadState_Swap(tstate) != NULL)
 		Py_FatalError(
 			"PyEval_AcquireThread: non-NULL old thread state");
@@ -263,7 +275,7 @@
 		Py_FatalError("PyEval_ReleaseThread: NULL thread state");
 	if (PyThreadState_Swap(NULL) != tstate)
 		Py_FatalError("PyEval_ReleaseThread: wrong thread state");
-	PyThread_release_lock(interpreter_lock);
+	PyEval_ReleaseLock();
 }
 
 /* This function is called from PyOS_AfterFork to ensure that newly
@@ -298,7 +310,7 @@
 		Py_FatalError("PyEval_SaveThread: NULL tstate");
 #ifdef WITH_THREAD
 	if (interpreter_lock)
-		PyThread_release_lock(interpreter_lock);
+		PyEval_ReleaseLock();
 #endif
 	return tstate;
 }
@@ -311,7 +323,7 @@
 #ifdef WITH_THREAD
 	if (interpreter_lock) {
 		int err = errno;
-		PyThread_acquire_lock(interpreter_lock, 1);
+		PyEval_AcquireLock();
 		errno = err;
 	}
 #endif
@@ -837,11 +849,11 @@
 
 				if (PyThreadState_Swap(NULL) != tstate)
 					Py_FatalError("ceval: tstate mix-up");
-				PyThread_release_lock(interpreter_lock);
+				PyEval_ReleaseLock();
 
 				/* Other threads may run now */
 
-				PyThread_acquire_lock(interpreter_lock, 1);
+				PyEval_AcquireLock();
 				if (PyThreadState_Swap(tstate) != NULL)
 					Py_FatalError("ceval: orphan tstate");
 
Index: Python/pythonrun.c
===================================================================
--- Python/pythonrun.c	(revision 60023)
+++ Python/pythonrun.c	(working copy)
@@ -440,6 +440,8 @@
 		_Py_PrintReferences(stderr);
 #endif /* Py_TRACE_REFS */
 
+	PyEval_StayForever();
+
 	/* Clear interpreter state */
 	PyInterpreterState_Clear(interp);