diff -r 1c54def5947c Python/import.c
--- a/Python/import.c	Mon Nov 05 00:55:06 2012 +0100
+++ b/Python/import.c	Tue Nov 06 16:07:43 2012 +0100
@@ -563,13 +563,12 @@
 
 /* Magic for extension modules (built-in as well as dynamically
    loaded).  To prevent initializing an extension module more than
-   once, we keep a static dictionary 'extensions' keyed by module name
-   (for built-in modules) or by filename (for dynamically loaded
-   modules), containing these modules.  A copy of the module's
-   dictionary is stored by calling _PyImport_FixupExtension()
-   immediately after the module initialization function succeeds.  A
-   copy can be retrieved from there by calling
-   _PyImport_FindExtension(). */
+   once, we keep a static dictionary 'extensions' keyed by by the tuple (module
+   name, module name)  (for built-in modules) or by (filename, module name)
+   (for dynamically loaded modules) , containing these modules.  A copy of the
+   module's dictionary is stored by calling _PyImport_FixupExtension()
+   immediately after the module initialization function succeeds.  A copy can
+   be retrieved from there by calling _PyImport_FindExtension(). */
 
 PyObject *
 _PyImport_FixupExtension(char *name, char *filename)
@@ -593,7 +592,7 @@
     copy = PyDict_Copy(dict);
     if (copy == NULL)
         return NULL;
-    PyDict_SetItemString(extensions, filename, copy);
+    PyDict_SetItem(extensions, Py_BuildValue("(ss)", filename, name), copy);
     Py_DECREF(copy);
     return copy;
 }
@@ -604,7 +603,7 @@
     PyObject *dict, *mod, *mdict;
     if (extensions == NULL)
         return NULL;
-    dict = PyDict_GetItemString(extensions, filename);
+    dict = PyDict_GetItem(extensions, Py_BuildValue("(ss)", filename, name));
     if (dict == NULL)
         return NULL;
     mod = PyImport_AddModule(name);