diff -r 2028aed246c0 Lib/multiprocessing/synchronize.py
--- a/Lib/multiprocessing/synchronize.py	Fri Oct 23 09:51:16 2015 -0700
+++ b/Lib/multiprocessing/synchronize.py	Sat Oct 24 01:29:15 2015 +0100
@@ -259,7 +259,12 @@
 
         try:
             # wait for notification or timeout
-            return self._wait_semaphore.acquire(True, timeout)
+            notified = self._wait_semaphore.acquire(True, timeout)
+        except:
+            notified = False
+            raise
+        else:
+            return notified
         finally:
             # indicate that this thread has woken
             self._woken_count.release()
@@ -268,16 +273,15 @@
             for i in range(count):
                 self._lock.acquire()
 
+            # decrement counters since wasn't notified
+            if not notified:
+                self._woken_count.acquire(False)
+                self._sleeping_count.acquire(False)
+
     def notify(self):
         assert self._lock._semlock._is_mine(), 'lock is not owned'
         assert not self._wait_semaphore.acquire(False)
 
-        # to take account of timeouts since last notify() we subtract
-        # woken_count from sleeping_count and rezero woken_count
-        while self._woken_count.acquire(False):
-            res = self._sleeping_count.acquire(False)
-            assert res
-
         if self._sleeping_count.acquire(False): # try grabbing a sleeper
             self._wait_semaphore.release()      # wake up one sleeper
             self._woken_count.acquire()         # wait for the sleeper to wake
@@ -289,12 +293,6 @@
         assert self._lock._semlock._is_mine(), 'lock is not owned'
         assert not self._wait_semaphore.acquire(False)
 
-        # to take account of timeouts since last notify*() we subtract
-        # woken_count from sleeping_count and rezero woken_count
-        while self._woken_count.acquire(False):
-            res = self._sleeping_count.acquire(False)
-            assert res
-
         sleepers = 0
         while self._sleeping_count.acquire(False):
             self._wait_semaphore.release()        # wake up one sleeper