From 81dee6b4d4acc061e568e10f976eb77b084ddd26 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <solipsis@pitrou.net>
Date: Mon, 11 Apr 2011 00:18:59 +0200
Subject: [PATCH 1/2] =?UTF-8?q?Issue=20#8428:=20Fix=20a=20race=20condition?=
 =?UTF-8?q?=20in=20multiprocessing.Pool=20when=20terminating=20worker=20pr?=
 =?UTF-8?q?ocesses:=20new=20processes=20would=20be=20spawned=20while=20the?=
 =?UTF-8?q?=20pool=20is=20being=20shut=20down.=20=20Patch=20by=20Charles-F?=
 =?UTF-8?q?ran=C3=A7ois=20Natali.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 Lib/multiprocessing/pool.py | 9 +++++++--
 Misc/NEWS                   | 4 ++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
index ff7c29c85b6..efa0056732b 100644
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -322,6 +322,8 @@ class Pool(object):
         while pool._worker_handler._state == RUN and pool._state == RUN:
             pool._maintain_pool()
             time.sleep(0.1)
+        # send sentinel to stop workers
+        pool._taskqueue.put(None)
         debug('worker handler exiting')
 
     @staticmethod
@@ -440,7 +442,6 @@ class Pool(object):
         if self._state == RUN:
             self._state = CLOSE
             self._worker_handler._state = CLOSE
-            self._taskqueue.put(None)
 
     def terminate(self):
         debug('terminating pool')
@@ -474,7 +475,6 @@ class Pool(object):
 
         worker_handler._state = TERMINATE
         task_handler._state = TERMINATE
-        taskqueue.put(None)                 # sentinel
 
         debug('helping task handler/workers to finish')
         cls._help_stuff_finish(inqueue, task_handler, len(pool))
@@ -484,6 +484,11 @@ class Pool(object):
         result_handler._state = TERMINATE
         outqueue.put(None)                  # sentinel
 
+        # We must wait for the worker handler to exit before terminating
+        # workers because we don't want workers to be restarted behind our back.
+        debug('joining worker handler')
+        worker_handler.join()
+
         # Terminate workers which haven't already finished.
         if pool and hasattr(pool[0], 'terminate'):
             debug('terminating workers')
diff --git a/Misc/NEWS b/Misc/NEWS
index b5dc98b2388..413f387c47d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -53,6 +53,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #8428: Fix a race condition in multiprocessing.Pool when terminating
+  worker processes: new processes would be spawned while the pool is being
+  shut down.  Patch by Charles-François Natali.
+
 - Issue #7311: fix html.parser to accept non-ASCII attribute values.
 
 - Issue #11605: email.parser.BytesFeedParser was incorrectly converting multipart

From bed9a5b6b38e30b4a207237ac9753cbfa0f2ae99 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <solipsis@pitrou.net>
Date: Mon, 11 Apr 2011 00:20:23 +0200
Subject: [PATCH 2/2] Issue #11814: Fix likely typo in
 multiprocessing.Pool._terminate().

---
 Lib/multiprocessing/pool.py | 2 +-
 Misc/NEWS                   | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
index efa0056732b..92170f2ee8c 100644
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -500,7 +500,7 @@ class Pool(object):
         task_handler.join()
 
         debug('joining result handler')
-        task_handler.join()
+        result_handler.join()
 
         if pool and hasattr(pool[0], 'terminate'):
             debug('joining pool workers')
diff --git a/Misc/NEWS b/Misc/NEWS
index 413f387c47d..e0e6bd222a0 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -53,6 +53,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #11814: Fix likely typo in multiprocessing.Pool._terminate().
+
 - Issue #8428: Fix a race condition in multiprocessing.Pool when terminating
   worker processes: new processes would be spawned while the pool is being
   shut down.  Patch by Charles-François Natali.