diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -764,9 +764,6 @@ def checkfolding(path):
     except:
         return True
 
-_umask = os.umask(0)
-os.umask(_umask)
-
 def checkexec(path):
     """
     Check whether the given path is on a filesystem with UNIX-like exec flags