diff --git a/Lib/filecmp.py b/Lib/filecmp.py
index 4728317..3a79381 100644
--- a/Lib/filecmp.py
+++ b/Lib/filecmp.py
@@ -268,7 +268,7 @@
 def _cmp(a, b, sh, abs=abs, cmp=cmp):
     try:
         return not abs(cmp(a, b, sh))
-    except os.error:
+    except (os.error, IOError):
         return 2