Mark dispatch of broadcast message as blocking section

celery/worker/pidbox.py

@@ -3,6 +3,7 @@ from __future__ import absolute_import
 import socket
 import threading
 
+from kombu.async import maybe_block
 from kombu.common import ignore_errors
 from kombu.utils.encoding import safe_str
 
@@ -34,7 +35,8 @@ class Pidbox(object):
         self._forward_clock()  # just increase clock as clients usually don't
                                # have a valid clock to adjust with.
         try:
-            self.node.handle_message(body, message)
+            with maybe_block():
+                self.node.handle_message(body, message)
         except KeyError as exc:
             error('No such control command: %s', exc)
         except Exception as exc: