diff --git a/Lib/trace.py b/Lib/trace.py
index 9ce240f..e6316b6 100644
--- a/Lib/trace.py
+++ b/Lib/trace.py
@@ -117,7 +117,7 @@
         self._mods = modules or []
         self._dirs = dirs or []
 
-        self._dirs = map(os.path.normpath, self._dirs)
+        self._dirs = list(map(os.path.normpath, self._dirs))
         self._ignore = { '<string>': 1 }
 
     def names(self, filename, modulename):
diff --git a/Misc/NEWS b/Misc/NEWS
index 0a99773..aa33a4b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -82,6 +82,9 @@
 Library
 -------
 
+- Issue #6666: fix bug in trace.py that applied the list of directories
+  to be ignored only to the first file.  Noted by Bogdan Opanchuk.
+
 - Issue #7597: curses.use_env() can now be called before initscr().
   Noted by Kan-Ru Chen.