diff --git a/ChangeLog b/ChangeLog
index c25f72594c..a38f86ed3a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri May  2 23:55:15 2008  Tanaka Akira  <akr@fsij.org>
+
+	* variable.c (rb_define_hooked_variable): guard *var from GC to
+	  prevent collecting argf under RUBY_DEBUG=gc_stress.
+
 Fri May  2 17:29:59 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* range.c (range_step): call to_int if step is not a numeric
diff --git a/variable.c b/variable.c
index 154f0872b0..a935c51d3a 100644
--- a/variable.c
+++ b/variable.c
@@ -455,13 +455,20 @@ rb_define_hooked_variable(
     void  (*setter)(ANYARGS))
 {
     struct global_variable *gvar;
-    ID id = global_id(name);
+    ID id;
+    VALUE tmp;
+    
+    if (var)
+        tmp = *var;
 
+    id = global_id(name);
     gvar = rb_global_entry(id)->var;
     gvar->data = (void*)var;
     gvar->getter = getter?getter:var_getter;
     gvar->setter = setter?setter:var_setter;
     gvar->marker = var_marker;
+
+    RB_GC_GUARD(tmp);
 }
 
 void