--- ruby-1.8.6-p420/error.c.tainted	2008-08-04 12:16:55.000000000 +0900
+++ ruby-1.8.6-p420/error.c	2011-02-21 04:44:14.000000000 +0900
@@ -404,7 +404,6 @@
     VALUE mesg = rb_attr_get(exc, rb_intern("mesg"));
 
     if (NIL_P(mesg)) return rb_class_name(CLASS_OF(exc));
-    if (OBJ_TAINTED(exc)) OBJ_TAINT(mesg);
     return mesg;
 }
 
@@ -668,10 +667,9 @@
     if (NIL_P(mesg)) return rb_class_name(CLASS_OF(exc));
     StringValue(str);
     if (str != mesg) {
-	rb_iv_set(exc, "mesg", mesg = str);
+	OBJ_INFECT(str, mesg);
     }
-    if (OBJ_TAINTED(exc)) OBJ_TAINT(mesg);
-    return mesg;
+    return str;
 }
 
 /*