bpo-19675: Terminate processes if construction of a pool is failing. (GH-5614)

1 files changed, 10 insertions, 2 deletions

diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
index 574b5db5af..7a6d014901 100644
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -174,7 +174,15 @@ class Pool(object):
 
         self._processes = processes
         self._pool = []
-        self._repopulate_pool()
+        try:
+            self._repopulate_pool()
+        except Exception:
+            for p in self._pool:
+                if p.exitcode is None:
+                    p.terminate()
+            for p in self._pool:
+                p.join()
+            raise
 
         self._worker_handler = threading.Thread(
             target=Pool._handle_workers,
@@ -251,10 +259,10 @@ class Pool(object):
                               initargs, maxtasksperchild,
                               wrap_exception)
                        )
-            pool.append(w)
             w.name = w.name.replace('Process', 'PoolWorker')
             w.daemon = True
             w.start()
+            pool.append(w)
             util.debug('added worker')
 
     @staticmethod