diff --git a/Lib/logging/config.py b/Lib/logging/config.py
index 9ba3cca..0694d21 100644
--- a/Lib/logging/config.py
+++ b/Lib/logging/config.py
@@ -61,11 +61,14 @@
     """
     import configparser
 
-    cp = configparser.ConfigParser(defaults)
-    if hasattr(fname, 'readline'):
-        cp.read_file(fname)
+    if isinstance(fname, configparser.RawConfigParser):
+        cp = fname
     else:
-        cp.read(fname)
+        cp = configparser.ConfigParser(defaults)
+        if hasattr(fname, 'readline'):
+            cp.read_file(fname)
+        else:
+            cp.read(fname)
 
     formatters = _create_formatters(cp)
 
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index dc49fc1..a2a136b 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -26,6 +26,7 @@
 import logging.config
 
 import codecs
+import configparser
 import datetime
 import pickle
 import io
@@ -1279,6 +1280,24 @@
             # Original logger output is empty.
             self.assert_log_lines([])
 
+    def test_config0_using_cp_ok(self):
+        # A simple config file which overrides the default settings.
+        with captured_stdout() as output:
+            file = io.StringIO(textwrap.dedent(self.config0))
+            cp = configparser.ConfigParser()
+            cp.read_file(file)
+            logging.config.fileConfig(cp)
+            logger = logging.getLogger()
+            # Won't output anything
+            logger.info(self.next_message())
+            # Outputs a message
+            logger.error(self.next_message())
+            self.assert_log_lines([
+                ('ERROR', '2'),
+            ], stream=output)
+            # Original logger output is empty.
+            self.assert_log_lines([])
+
     def test_config1_ok(self, config=config1):
         # A config file defining a sub-parser as well.
         with captured_stdout() as output: