diff --git a/ChangeLog b/ChangeLog
index 4a79c668d8..de473c22ee 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Tue Oct  7 23:40:16 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* signal.c (rb_f_kill): get rid of deadlock as unhandled and
+	  discarded signals do not make interrupt_cond signaled.
+	  based on the patch by Kazuki Tsujimoto at [ruby-dev:48606].
+	  [Bug #9820]
+
 Tue Oct  7 22:43:44 2014  Masaki Suketa <masaki.suketa@nifty.ne.jp>
 
 	* ext/win32ole/win32ole_method.c: use typed data.
diff --git a/signal.c b/signal.c
index 171f5ac971..c42ce0aee0 100644
--- a/signal.c
+++ b/signal.c
@@ -487,7 +487,8 @@ rb_f_kill(int argc, const VALUE *argv)
 		  default:
 		    t = signal_ignored(sig);
 		    if (t) {
-			if (t < 0) ruby_kill(pid, sig);
+			if (t < 0 && kill(pid, sig))
+			    rb_sys_fail(0);
 			break;
 		    }
 		    signal_enque(sig);
diff --git a/test/ruby/test_signal.rb b/test/ruby/test_signal.rb
index 32068a407a..e74a2c4e1e 100644
--- a/test/ruby/test_signal.rb
+++ b/test/ruby/test_signal.rb
@@ -286,5 +286,10 @@ EOS
       assert_predicate(status, :signaled?, bug9820)
       assert_equal(trap, status.termsig, bug9820)
     end
+
+    if Signal.list['CONT']
+      bug9820 = '[ruby-dev:48606] [Bug #9820]'
+      assert_ruby_status(['-e', 'Process.kill(:CONT, $$)'])
+    end
   end if Process.respond_to?(:kill)
 end