diff --git a/ChangeLog b/ChangeLog
index 4432e1d3b0..609ab87068 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Mar  8 23:49:45 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* process.c (proc_setgroups): cleanup.
+
 Tue Mar  8 23:40:30 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* test/misc/test_ruby_mode.rb: test for ruby-mode.el.
diff --git a/process.c b/process.c
index 08a0258c13..559fe1d838 100644
--- a/process.c
+++ b/process.c
@@ -4639,10 +4639,10 @@ proc_setgroups(VALUE obj, VALUE ary)
 
     Check_Type(ary, T_ARRAY);
 
-    if (RARRAY_LEN(ary) > maxgroups())
+    ngroups = RARRAY_LENINT(ary);
+    if (ngroups > maxgroups())
 	rb_raise(rb_eArgError, "too many groups, %d max", maxgroups());
 
-    ngroups = RARRAY_LENINT(ary);
     groups = ALLOCA_N(rb_gid_t, ngroups);
 
     for (i = 0; i < ngroups; i++) {