diff --git a/ChangeLog b/ChangeLog
index 5e1e360a6c..e9db07a855 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sat Aug 18 15:59:52 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* process.c (detach_process_watcher): should not pass the pointer
+	  to an auto variable to the thread to be created.  pointed and
+	  fix by KUBO Takehiro <kubo at jiubao.org>  [ruby-dev:30618]
+
 Sat Aug 18 12:24:30 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* sample/test.rb, test/ruby/test_system.rb(valid_syntax?): keep
diff --git a/process.c b/process.c
index 7df42393c6..bd1e5cea53 100644
--- a/process.c
+++ b/process.c
@@ -848,23 +848,22 @@ proc_waitall()
 }
 
 static VALUE
-detach_process_watcher(pid_p)
-    int *pid_p;
+detach_process_watcher(arg)
+    void *arg;
 {
-    int cpid, status;
+    int pid = (int)arg, status;
 
-    for (;;) {
-	cpid = rb_waitpid(*pid_p, &status, WNOHANG);
-	if (cpid != 0) return Qnil;
+    while (rb_waitpid(pid, &status, WNOHANG) == 0) {
 	rb_thread_sleep(1);
     }
+    return Qnil;
 }
 
 VALUE
 rb_detach_process(pid)
     int pid;
 {
-    return rb_thread_create(detach_process_watcher, (void*)&pid);
+    return rb_thread_create(detach_process_watcher, (void*)pid);
 }