diff --git a/ChangeLog b/ChangeLog
index 3c1ba5d4b9..31f9f28b2b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Dec 11 00:10:18 2004  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* io.c (io_reopen): [ruby-dev:25150]
+
 Fri Dec 10 08:39:27 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/socket/socket.c (sock_listen): get OpenFile just before calling
diff --git a/io.c b/io.c
index 1e77e5b4ba..ec16438ffd 100644
--- a/io.c
+++ b/io.c
@@ -3172,6 +3172,7 @@ io_reopen(io, nfile)
 	}
 	else {
 	    fclose(fptr->f);
+	    fptr->f = NULL;
 	    if (dup2(fd2, fd) < 0)
 		rb_sys_fail(orig->path);
 	    fptr->f = rb_fdopen(fd, mode);