diff --git a/ChangeLog b/ChangeLog
index 14bc6693b5..5447ffb0d3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Sep  5 01:22:23 2008  Tanaka Akira  <akr@fsij.org>
+
+	* io.c (argf_mark): mark p->encs.ecopts.
+
 Fri Sep  5 00:45:07 2008  Tanaka Akira  <akr@fsij.org>
 
 	* transcode_data.h (rb_transcoder): rename fields:
diff --git a/io.c b/io.c
index ced821a6b5..e44d2cfe22 100644
--- a/io.c
+++ b/io.c
@@ -5679,6 +5679,7 @@ argf_mark(void *ptr)
     rb_gc_mark(p->current_file);
     rb_gc_mark(p->lineno);
     rb_gc_mark(p->argv);
+    rb_gc_mark(p->encs.ecopts);
 }
 
 static void