logging: Added threading interlock in basicConfig().

Lib/logging/__init__.py

@@ -1459,6 +1459,10 @@ def basicConfig(**kwargs):
     using sys.stdout or sys.stderr), whereas FileHandler closes its stream
     when the handler is closed.
     """
+    # Add thread safety in case someone mistakenly calls
+    # basicConfig() from multiple threads
+    _acquireLock()
+    try:
         if len(root.handlers) == 0:
             filename = kwargs.get("filename")
             if filename:
@@ -1475,6 +1479,8 @@ def basicConfig(**kwargs):
             level = kwargs.get("level")
             if level is not None:
                 root.setLevel(level)
+    finally:
+        _releaseLock()
 
 #---------------------------------------------------------------------------
 # Utility functions at module level.