Issue #14666: stop multiprocessing's resource-sharing thread after the tests are done.

Also, block delivery of signals to that thread. Patch by Richard Oudkerk.

This will hopefully fix sporadic freezes on the FreeBSD 9.0 buildbot.

Lib/multiprocessing/reduction.py

@@ -40,6 +40,7 @@
 import socket
 import threading
 import struct
+import signal
 
 from multiprocessing import current_process
 from multiprocessing.util import register_after_fork, debug, sub_debug
@@ -209,6 +210,7 @@ def __init__(self):
         self._lock = threading.Lock()
         self._listener = None
         self._address = None
+        self._thread = None
         register_after_fork(self, ResourceSharer._afterfork)
 
     def register(self, send, close):
@@ -227,6 +229,24 @@ def get_connection(ident):
         c.send((key, os.getpid()))
         return c
 
+    def stop(self, timeout=None):
+        from .connection import Client
+        with self._lock:
+            if self._address is not None:
+                c = Client(self._address, authkey=current_process().authkey)
+                c.send(None)
+                c.close()
+                self._thread.join(timeout)
+                if self._thread.is_alive():
+                    sub_warn('ResourceSharer thread did not stop when asked')
+                self._listener.close()
+                self._thread = None
+                self._address = None
+                self._listener = None
+                for key, (send, close) in self._cache.items():
+                    close()
+                self._cache.clear()
+
     def _afterfork(self):
         for key, (send, close) in self._cache.items():
             close()
@@ -239,6 +259,7 @@ def _afterfork(self):
             self._listener.close()
         self._listener = None
         self._address = None
+        self._thread = None
 
     def _start(self):
         from .connection import Listener
@@ -249,12 +270,18 @@ def _start(self):
         t = threading.Thread(target=self._serve)
         t.daemon = True
         t.start()
+        self._thread = t
 
     def _serve(self):
+        if hasattr(signal, 'pthread_sigmask'):
+            signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
         while 1:
             try:
                 conn = self._listener.accept()
-                key, destination_pid = conn.recv()
+                msg = conn.recv()
+                if msg is None:
+                    break
+                key, destination_pid = msg
                 send, close = self._cache.pop(key)
                 send(conn, destination_pid)
                 close()

Lib/test/test_multiprocessing.py

@@ -1965,6 +1965,11 @@ class _TestPicklingConnections(BaseTestCase):
 
     ALLOWED_TYPES = ('processes',)
 
+    @classmethod
+    def tearDownClass(cls):
+        from multiprocessing.reduction import resource_sharer
+        resource_sharer.stop(timeout=5)
+
     @classmethod
     def _listener(cls, conn, families):
         for fam in families: