diff --git a/ChangeLog b/ChangeLog
index 3918ad5b4f..8d35baf50d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jul 21 10:25:52 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (prepare_getline_args): check if rs is a string when non-nil
+	  lim is given.  [ruby-dev:35610]
+
 Mon Jul 21 04:55:20 2008  Tanaka Akira  <akr@fsij.org>
 
 	* dir.c (dir_initialize): use rb_convert_type instead of
diff --git a/io.c b/io.c
index 9fa241f6c3..52216cff43 100644
--- a/io.c
+++ b/io.c
@@ -1892,7 +1892,10 @@ prepare_getline_args(int argc, VALUE *argv, VALUE *rsp, long *limit, VALUE io)
     }
     else {
 	rb_scan_args(argc, argv, "11", &rs, &lim);
-	if (NIL_P(lim) && !NIL_P(rs) && TYPE(rs) != T_STRING) {
+	if (!NIL_P(lim)) {
+	    StringValue(rs);
+	}
+	else if (!NIL_P(rs) && TYPE(rs) != T_STRING) {
 	    VALUE tmp = rb_check_string_type(rs);
 
 	    if (NIL_P(tmp)) {