diff -r 430a2b541709 Lib/asyncio/base_subprocess.py
--- a/Lib/asyncio/base_subprocess.py	Thu Feb 12 22:49:18 2015 +0100
+++ b/Lib/asyncio/base_subprocess.py	Thu Feb 12 22:54:30 2015 +0100
@@ -212,6 +212,7 @@ class BaseSubprocessTransport(transports
                 waiter.set_result(returncode)
         self._exit_waiters = None
 
+    @coroutine
     def _wait(self):
         """Wait until the process exit and return the process return code.
 
diff -r 430a2b541709 Lib/asyncio/locks.py
--- a/Lib/asyncio/locks.py	Thu Feb 12 22:49:18 2015 +0100
+++ b/Lib/asyncio/locks.py	Thu Feb 12 22:54:30 2015 +0100
@@ -162,6 +162,7 @@ class Lock:
         # always raises; that's how the with-statement works.
         pass
 
+    @coroutine
     def __iter__(self):
         # This is not a coroutine.  It is meant to enable the idiom:
         #
@@ -362,6 +363,7 @@ class Condition:
     def __exit__(self, *args):
         pass
 
+    @coroutine
     def __iter__(self):
         # See comment in Lock.__iter__().
         yield from self.acquire()
@@ -446,6 +448,7 @@ class Semaphore:
     def __exit__(self, *args):
         pass
 
+    @coroutine
     def __iter__(self):
         # See comment in Lock.__iter__().
         yield from self.acquire()
diff -r 430a2b541709 Lib/asyncio/streams.py
--- a/Lib/asyncio/streams.py	Thu Feb 12 22:49:18 2015 +0100
+++ b/Lib/asyncio/streams.py	Thu Feb 12 22:54:30 2015 +0100
@@ -378,6 +378,7 @@ class StreamReader:
             else:
                 self._paused = True
 
+    @coroutine
     def _wait_for_data(self, func_name):
         """Wait until feed_data() or feed_eof() is called."""
         # StreamReader uses a future to link the protocol feed_data() method