diff -r 47618b00405b Lib/asyncio/base_events.py
--- a/Lib/asyncio/base_events.py	Sat Oct 19 10:45:48 2013 +0300
+++ b/Lib/asyncio/base_events.py	Sat Oct 19 21:39:04 2013 +0200
@@ -543,11 +543,6 @@
         else:
             self._ready.append(handle)
 
-    def _add_callback_signalsafe(self, handle):
-        """Like _add_callback() but called from a signal handler."""
-        self._add_callback(handle)
-        self._write_to_self()
-
     def _run_once(self):
         """Run one full iteration of the event loop.
 
diff -r 47618b00405b Lib/asyncio/proactor_events.py
--- a/Lib/asyncio/proactor_events.py	Sat Oct 19 10:45:48 2013 +0300
+++ b/Lib/asyncio/proactor_events.py	Sat Oct 19 21:39:04 2013 +0200
@@ -319,7 +319,7 @@
             f.add_done_callback(self._loop_self_reading)
 
     def _write_to_self(self):
-        self._csock.send(b'x')
+        self._csock.send(b'\x00')
 
     def _start_serving(self, protocol_factory, sock, ssl=None, server=None):
         assert not ssl, 'IocpEventLoop is incompatible with SSL.'
diff -r 47618b00405b Lib/asyncio/selector_events.py
--- a/Lib/asyncio/selector_events.py	Sat Oct 19 10:45:48 2013 +0300
+++ b/Lib/asyncio/selector_events.py	Sat Oct 19 21:39:04 2013 +0200
@@ -84,7 +84,8 @@
 
     def _write_to_self(self):
         try:
-            self._csock.send(b'x')
+            # send a payload that can't be a signal number
+            self._csock.send(b'\x00')
         except (BlockingIOError, InterruptedError):
             pass
 
diff -r 47618b00405b Lib/asyncio/unix_events.py
--- a/Lib/asyncio/unix_events.py	Sat Oct 19 10:45:48 2013 +0300
+++ b/Lib/asyncio/unix_events.py	Sat Oct 19 21:39:04 2013 +0200
@@ -8,6 +8,7 @@
 import signal
 import socket
 import stat
+import struct
 import subprocess
 import sys
 
@@ -71,8 +72,10 @@
         handle = events.make_handle(callback, args)
         self._signal_handlers[sig] = handle
 
+        # setup a dummy signal handler: we just want to be notified through the
+        # wakeup FD
         try:
-            signal.signal(sig, self._handle_signal)
+            signal.signal(sig, lambda *args: None)
         except OSError as exc:
             del self._signal_handlers[sig]
             if not self._signal_handlers:
@@ -86,15 +89,22 @@
             else:
                 raise
 
-    def _handle_signal(self, sig, arg):
-        """Internal helper that is the actual signal handler."""
-        handle = self._signal_handlers.get(sig)
-        if handle is None:
-            return  # Assume it's some race condition.
-        if handle._cancelled:
-            self.remove_signal_handler(sig)  # Remove it properly.
+    def _read_from_self(self):
+        try:
+            payload = self._ssock.recv(1)
+            sig = struct.unpack('B', payload)[0]
+        except (BlockingIOError, InterruptedError, struct.error):
+            pass
         else:
-            self._add_callback_signalsafe(handle)
+            handle = self._signal_handlers.get(sig)
+            if handle is None:
+                # it was either a call to _write_to_self()), or some race
+                # condition
+                return
+            if handle._cancelled:
+                self.remove_signal_handler(sig)  # Remove it properly.
+            else:
+                self._add_callback(handle)
 
     def remove_signal_handler(self, sig):
         """Remove a handler for a signal.  UNIX only.
diff -r 47618b00405b Lib/test/test_asyncio/test_events.py
--- a/Lib/test/test_asyncio/test_events.py	Sat Oct 19 10:45:48 2013 +0300
+++ b/Lib/test/test_asyncio/test_events.py	Sat Oct 19 21:39:04 2013 +0200
@@ -397,6 +397,7 @@
         def my_handler():
             nonlocal caught
             caught += 1
+            self.loop.stop()
 
         # Check error behavior first.
         self.assertRaises(
@@ -425,7 +426,7 @@
         self.loop.add_signal_handler(signal.SIGINT, my_handler)
         test_utils.run_briefly(self.loop)
         os.kill(os.getpid(), signal.SIGINT)
-        test_utils.run_briefly(self.loop)
+        self.loop.run_forever()
         self.assertEqual(caught, 1)
         # Removing it should restore the default handler.
         self.assertTrue(self.loop.remove_signal_handler(signal.SIGINT))
diff -r 47618b00405b Lib/test/test_asyncio/test_proactor_events.py
--- a/Lib/test/test_asyncio/test_proactor_events.py	Sat Oct 19 10:45:48 2013 +0300
+++ b/Lib/test/test_asyncio/test_proactor_events.py	Sat Oct 19 21:39:04 2013 +0200
@@ -427,7 +427,7 @@
 
     def test_write_to_self(self):
         self.loop._write_to_self()
-        self.csock.send.assert_called_with(b'x')
+        self.csock.send.assert_called_with(b'\x00')
 
     def test_process_events(self):
         self.loop._process_events([])
diff -r 47618b00405b Lib/test/test_asyncio/test_unix_events.py
--- a/Lib/test/test_asyncio/test_unix_events.py	Sat Oct 19 10:45:48 2013 +0300
+++ b/Lib/test/test_asyncio/test_unix_events.py	Sat Oct 19 21:39:04 2013 +0200
@@ -37,17 +37,6 @@
         self.assertRaises(
             ValueError, self.loop._check_signal, signal.NSIG + 1)
 
-    def test_handle_signal_no_handler(self):
-        self.loop._handle_signal(signal.NSIG + 1, ())
-
-    def test_handle_signal_cancelled_handler(self):
-        h = events.Handle(unittest.mock.Mock(), ())
-        h.cancel()
-        self.loop._signal_handlers[signal.NSIG + 1] = h
-        self.loop.remove_signal_handler = unittest.mock.Mock()
-        self.loop._handle_signal(signal.NSIG + 1, ())
-        self.loop.remove_signal_handler.assert_called_with(signal.NSIG + 1)
-
     @unittest.mock.patch('asyncio.unix_events.signal')
     def test_add_signal_handler_setup_error(self, m_signal):
         m_signal.NSIG = signal.NSIG