diff --git a/mitogen/master.py b/mitogen/master.py
index 4fb535f0..e069902d 100644
--- a/mitogen/master.py
+++ b/mitogen/master.py
@@ -136,8 +136,14 @@ def is_stdlib_name(modname):
     if module is None:
         return False
 
+    try:
+        import importlib
+        return modname in importlib.sys.stdlib_module_names
+    except ImportError:
+        pass
+
     # six installs crap with no __file__
-    modpath = os.path.abspath(getattr(module, '__file__', ''))
+    modpath = os.path.abspath(getattr(module, '__file__', '') or '')
     return is_stdlib_path(modpath)