diff --git a/ChangeLog b/ChangeLog
index 0e9a1a328f..1f2bf0848c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Tue Jul 12 20:02:35 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* signal.c (reserved_signal_p): reverted a part of r32523.
+	  chikanaga noticed trap(:CHLD) has some realworld usecase.
+	* test/ruby/test_signal.rb (TestSignal#test_reserved_signal):
+	  ditto.
+
 Tue Jul 12 17:12:45 2011  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* vm_method.c (rb_add_method): should not call method_added hook
diff --git a/signal.c b/signal.c
index 103514ae64..3d9a1dbde5 100644
--- a/signal.c
+++ b/signal.c
@@ -896,16 +896,6 @@ int reserved_signal_p(int signo)
 	return 1;
 #endif
 
-/* On some OSs, wait() never return if SIGCHLD handler is installed. */
-#ifdef SIGCHLD
-    if (signo == SIGCHLD)
-	return 1;
-#endif
-#ifdef SIGCLD
-    if (signo == SIGCLD)
-	return 1;
-#endif
-
     return 0;
 }
 
diff --git a/test/ruby/test_signal.rb b/test/ruby/test_signal.rb
index cd1f2c04b1..13bb771120 100644
--- a/test/ruby/test_signal.rb
+++ b/test/ruby/test_signal.rb
@@ -237,12 +237,6 @@ EOS
     assert_raise(ArgumentError) {
       Signal.trap(:VTALRM) {}
     }
-    assert_raise(ArgumentError) {
-      Signal.trap(:CHLD) {}
-    }
-    assert_raise(ArgumentError) {
-      Signal.trap(:CLD) {}
-    }
   end
 
 end