diff --git a/ChangeLog b/ChangeLog
index c5243aae9d..1ab47f768d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Oct 26 13:30:28 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (read_all): use the given buffer to read when needs readconv.
+	  based on the patch by wanabe <s.wanabe AT gmail.com> at
+	  [ruby-dev:36931].
+
 Sun Oct 26 07:57:35 2008  Eric Hodel  <drbrain@segment7.net>
 
 	* lib/rubygems*:  Update to RubyGems 1.3.1 r1909.
diff --git a/io.c b/io.c
index bfeefef432..125180b925 100644
--- a/io.c
+++ b/io.c
@@ -1556,7 +1556,7 @@ read_all(rb_io_t *fptr, long siz, VALUE str)
     int cr;
 
     if (NEED_READCONV(fptr)) {
-        VALUE str = rb_str_new(NULL, 0);
+        if (!NIL_P(str)) rb_str_set_len(str, 0);
         make_readconv(fptr);
         while (1) {
             if (fptr->cbuf_len) {