diff --git a/ChangeLog b/ChangeLog
index 6ff17fbbcb..54e4e824d4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jan 16 18:03:10 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (pipe_open, rb_io_s_popen): clear temporary object to release
+	  and prevent from GC.
+
 Wed Jan 16 17:55:07 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* numeric.c (fix_quo): typo. a patch from Shin-ichiro HARA
diff --git a/io.c b/io.c
index f1ce12e865..597f56cfe0 100644
--- a/io.c
+++ b/io.c
@@ -3626,6 +3626,7 @@ pipe_open(const char *cmd, int argc, VALUE *argv, const char *mode)
 	exename = cmd;
 	cmdbuf = rb_str_tmp_new(rb_w32_argv_size(args));
 	cmd = rb_w32_join_argv(RSTRING_PTR(cmdbuf), args);
+	rb_str_resize(argbuf, 0);
     }
     while ((pid = rb_w32_pipe_exec(cmd, exename, openmode, &fd, &write_fd)) == -1) {
 	/* exec failed */
@@ -3775,6 +3776,7 @@ rb_io_s_popen(int argc, VALUE *argv, VALUE klass)
 	tmp = rb_ary_dup(tmp);
 	RBASIC(tmp)->klass = 0;
 	port = pipe_open_v(RARRAY_LEN(tmp), RARRAY_PTR(tmp), mode);
+	rb_ary_clear(tmp);
     }
     else {
 	SafeStringValue(pname);