Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 37412)
+++ wp-includes/functions.php	(working copy)
@@ -1604,7 +1604,7 @@
 
 	// We need to find the permissions of the parent folder that exists and inherit that.
 	$target_parent = dirname( $target );
-	while ( '.' != $target_parent && ! is_dir( $target_parent ) ) {
+	while ( '.' != $target_parent && ! is_dir( $target_parent ) && @is_readable( $target_parent ) ) {
 		$target_parent = dirname( $target_parent );
 	}