diff --git a/Lib/multiprocessing/managers.py b/Lib/multiprocessing/managers.py index a5d2f536139..040f4674d73 100644 --- a/Lib/multiprocessing/managers.py +++ b/Lib/multiprocessing/managers.py @@ -759,22 +759,29 @@ class BaseProxy(object): _address_to_local = {} _mutex = util.ForkAwareThreadLock() + # Each instance gets a `_serial` number. Unlike `id(...)`, this number + # is never reused. + _next_serial = 1 + def __init__(self, token, serializer, manager=None, authkey=None, exposed=None, incref=True, manager_owned=False): with BaseProxy._mutex: - tls_idset = BaseProxy._address_to_local.get(token.address, None) - if tls_idset is None: - tls_idset = util.ForkAwareLocal(), ProcessLocalSet() - BaseProxy._address_to_local[token.address] = tls_idset + tls_serials = BaseProxy._address_to_local.get(token.address, None) + if tls_serials is None: + tls_serials = util.ForkAwareLocal(), ProcessLocalSet() + BaseProxy._address_to_local[token.address] = tls_serials + + self._serial = BaseProxy._next_serial + BaseProxy._next_serial += 1 # self._tls is used to record the connection used by this # thread to communicate with the manager at token.address - self._tls = tls_idset[0] + self._tls = tls_serials[0] - # self._idset is used to record the identities of all shared - # objects for which the current process owns references and + # self._all_serials is a set used to record the identities of all + # shared objects for which the current process owns references and # which are in the manager at token.address - self._idset = tls_idset[1] + self._all_serials = tls_serials[1] self._token = token self._id = self._token.id @@ -857,20 +864,20 @@ def _incref(self): dispatch(conn, None, 'incref', (self._id,)) util.debug('INCREF %r', self._token.id) - self._idset.add(self._id) + self._all_serials.add(self._serial) state = self._manager and self._manager._state self._close = util.Finalize( self, BaseProxy._decref, - args=(self._token, self._authkey, state, - self._tls, self._idset, self._Client), + args=(self._token, self._serial, self._authkey, state, + self._tls, self._all_serials, self._Client), exitpriority=10 ) @staticmethod - def _decref(token, authkey, state, tls, idset, _Client): - idset.discard(token.id) + def _decref(token, serial, authkey, state, tls, idset, _Client): + idset.discard(serial) # check whether manager is still alive if state is None or state.value == State.STARTED: diff --git a/Misc/ACKS b/Misc/ACKS index dce322fc867..08cd293eac3 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -733,6 +733,7 @@ Larry Hastings Tim Hatch Zac Hatfield-Dodds Shane Hathaway +Akinori Hattori Michael Haubenwallner Janko Hauser Flavian Hautbois diff --git a/Misc/NEWS.d/next/Library/2022-10-15-10-18-20.gh-issue-71936.MzJjc_.rst b/Misc/NEWS.d/next/Library/2022-10-15-10-18-20.gh-issue-71936.MzJjc_.rst new file mode 100644 index 00000000000..a0959cc086f --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-10-15-10-18-20.gh-issue-71936.MzJjc_.rst @@ -0,0 +1 @@ +Fix a race condition in :class:`multiprocessing.pool.Pool`.