diff --git a/lib/linux/chmod.c b/lib/linux/chmod.c
index 235b3456..54509b53 100644
--- a/lib/linux/chmod.c
+++ b/lib/linux/chmod.c
@@ -25,5 +25,7 @@
 int
 chmod (char const *file_name, mode_t mask)
 {
-  return _sys_call2 (SYS_chmod, (long) file_name, (long) mask);
+  long long_file_name = file_name;
+  long long_mask = mask;
+  return _sys_call2 (SYS_chmod, long_file_name, long_mask);
 }