mirror of https://github.com/python/cpython
333 lines
12 KiB
Python
333 lines
12 KiB
Python
import contextlib
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import queue
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import signal
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import sys
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import time
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import unittest
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import unittest.mock
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from pickle import PicklingError
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from concurrent import futures
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from concurrent.futures.process import BrokenProcessPool, _ThreadWakeup
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from test import support
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from .util import (
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create_executor_tests, setup_module,
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ProcessPoolForkMixin, ProcessPoolForkserverMixin, ProcessPoolSpawnMixin)
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def _crash(delay=None):
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"""Induces a segfault."""
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if delay:
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time.sleep(delay)
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import faulthandler
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faulthandler.disable()
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faulthandler._sigsegv()
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def _crash_with_data(data):
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"""Induces a segfault with dummy data in input."""
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_crash()
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def _exit():
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"""Induces a sys exit with exitcode 1."""
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sys.exit(1)
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def _raise_error(Err):
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"""Function that raises an Exception in process."""
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raise Err()
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def _raise_error_ignore_stderr(Err):
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"""Function that raises an Exception in process and ignores stderr."""
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import io
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sys.stderr = io.StringIO()
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raise Err()
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def _return_instance(cls):
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"""Function that returns a instance of cls."""
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return cls()
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class CrashAtPickle(object):
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"""Bad object that triggers a segfault at pickling time."""
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def __reduce__(self):
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_crash()
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class CrashAtUnpickle(object):
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"""Bad object that triggers a segfault at unpickling time."""
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def __reduce__(self):
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return _crash, ()
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class ExitAtPickle(object):
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"""Bad object that triggers a process exit at pickling time."""
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def __reduce__(self):
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_exit()
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class ExitAtUnpickle(object):
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"""Bad object that triggers a process exit at unpickling time."""
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def __reduce__(self):
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return _exit, ()
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class ErrorAtPickle(object):
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"""Bad object that triggers an error at pickling time."""
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def __reduce__(self):
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from pickle import PicklingError
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raise PicklingError("Error in pickle")
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class ErrorAtUnpickle(object):
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"""Bad object that triggers an error at unpickling time."""
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def __reduce__(self):
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from pickle import UnpicklingError
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return _raise_error_ignore_stderr, (UnpicklingError, )
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class ExecutorDeadlockTest:
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TIMEOUT = support.LONG_TIMEOUT
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def _fail_on_deadlock(self, executor):
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# If we did not recover before TIMEOUT seconds, consider that the
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# executor is in a deadlock state and forcefully clean all its
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# composants.
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import faulthandler
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from tempfile import TemporaryFile
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with TemporaryFile(mode="w+") as f:
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faulthandler.dump_traceback(file=f)
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f.seek(0)
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tb = f.read()
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for p in executor._processes.values():
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p.terminate()
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# This should be safe to call executor.shutdown here as all possible
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# deadlocks should have been broken.
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executor.shutdown(wait=True)
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print(f"\nTraceback:\n {tb}", file=sys.__stderr__)
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self.fail(f"Executor deadlock:\n\n{tb}")
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def _check_crash(self, error, func, *args, ignore_stderr=False):
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# test for deadlock caused by crashes in a pool
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self.executor.shutdown(wait=True)
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executor = self.executor_type(
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max_workers=2, mp_context=self.get_context())
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res = executor.submit(func, *args)
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if ignore_stderr:
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cm = support.captured_stderr()
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else:
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cm = contextlib.nullcontext()
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try:
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with self.assertRaises(error):
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with cm:
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res.result(timeout=self.TIMEOUT)
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except futures.TimeoutError:
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# If we did not recover before TIMEOUT seconds,
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# consider that the executor is in a deadlock state
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self._fail_on_deadlock(executor)
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executor.shutdown(wait=True)
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def test_error_at_task_pickle(self):
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# Check problem occurring while pickling a task in
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# the task_handler thread
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self._check_crash(PicklingError, id, ErrorAtPickle())
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def test_exit_at_task_unpickle(self):
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# Check problem occurring while unpickling a task on workers
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self._check_crash(BrokenProcessPool, id, ExitAtUnpickle())
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def test_error_at_task_unpickle(self):
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# gh-109832: Restore stderr overriden by _raise_error_ignore_stderr()
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self.addCleanup(setattr, sys, 'stderr', sys.stderr)
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# Check problem occurring while unpickling a task on workers
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self._check_crash(BrokenProcessPool, id, ErrorAtUnpickle())
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def test_crash_at_task_unpickle(self):
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# Check problem occurring while unpickling a task on workers
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self._check_crash(BrokenProcessPool, id, CrashAtUnpickle())
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def test_crash_during_func_exec_on_worker(self):
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# Check problem occurring during func execution on workers
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self._check_crash(BrokenProcessPool, _crash)
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def test_exit_during_func_exec_on_worker(self):
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# Check problem occurring during func execution on workers
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self._check_crash(SystemExit, _exit)
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def test_error_during_func_exec_on_worker(self):
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# Check problem occurring during func execution on workers
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self._check_crash(RuntimeError, _raise_error, RuntimeError)
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def test_crash_during_result_pickle_on_worker(self):
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# Check problem occurring while pickling a task result
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# on workers
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self._check_crash(BrokenProcessPool, _return_instance, CrashAtPickle)
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def test_exit_during_result_pickle_on_worker(self):
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# Check problem occurring while pickling a task result
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# on workers
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self._check_crash(SystemExit, _return_instance, ExitAtPickle)
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def test_error_during_result_pickle_on_worker(self):
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# Check problem occurring while pickling a task result
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# on workers
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self._check_crash(PicklingError, _return_instance, ErrorAtPickle)
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def test_error_during_result_unpickle_in_result_handler(self):
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# gh-109832: Restore stderr overriden by _raise_error_ignore_stderr()
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self.addCleanup(setattr, sys, 'stderr', sys.stderr)
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# Check problem occurring while unpickling a task in
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# the result_handler thread
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self._check_crash(BrokenProcessPool,
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_return_instance, ErrorAtUnpickle,
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ignore_stderr=True)
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def test_exit_during_result_unpickle_in_result_handler(self):
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# Check problem occurring while unpickling a task in
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# the result_handler thread
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self._check_crash(BrokenProcessPool, _return_instance, ExitAtUnpickle)
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def test_shutdown_deadlock(self):
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# Test that the pool calling shutdown do not cause deadlock
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# if a worker fails after the shutdown call.
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self.executor.shutdown(wait=True)
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with self.executor_type(max_workers=2,
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mp_context=self.get_context()) as executor:
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self.executor = executor # Allow clean up in fail_on_deadlock
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f = executor.submit(_crash, delay=.1)
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executor.shutdown(wait=True)
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with self.assertRaises(BrokenProcessPool):
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f.result()
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def test_shutdown_deadlock_pickle(self):
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# Test that the pool calling shutdown with wait=False does not cause
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# a deadlock if a task fails at pickle after the shutdown call.
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# Reported in bpo-39104.
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self.executor.shutdown(wait=True)
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with self.executor_type(max_workers=2,
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mp_context=self.get_context()) as executor:
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self.executor = executor # Allow clean up in fail_on_deadlock
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# Start the executor and get the executor_manager_thread to collect
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# the threads and avoid dangling thread that should be cleaned up
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# asynchronously.
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executor.submit(id, 42).result()
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executor_manager = executor._executor_manager_thread
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# Submit a task that fails at pickle and shutdown the executor
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# without waiting
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f = executor.submit(id, ErrorAtPickle())
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executor.shutdown(wait=False)
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with self.assertRaises(PicklingError):
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f.result()
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# Make sure the executor is eventually shutdown and do not leave
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# dangling threads
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executor_manager.join()
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def test_crash_big_data(self):
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# Test that there is a clean exception instead of a deadlock when a
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# child process crashes while some data is being written into the
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# queue.
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# https://github.com/python/cpython/issues/94777
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self.executor.shutdown(wait=True)
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data = "a" * support.PIPE_MAX_SIZE
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with self.executor_type(max_workers=2,
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mp_context=self.get_context()) as executor:
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self.executor = executor # Allow clean up in fail_on_deadlock
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with self.assertRaises(BrokenProcessPool):
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list(executor.map(_crash_with_data, [data] * 10))
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executor.shutdown(wait=True)
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def test_gh105829_should_not_deadlock_if_wakeup_pipe_full(self):
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# Issue #105829: The _ExecutorManagerThread wakeup pipe could
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# fill up and block. See: https://github.com/python/cpython/issues/105829
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# Lots of cargo culting while writing this test, apologies if
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# something is really stupid...
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self.executor.shutdown(wait=True)
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if not hasattr(signal, 'alarm'):
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raise unittest.SkipTest(
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"Tested platform does not support the alarm signal")
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def timeout(_signum, _frame):
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import faulthandler
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faulthandler.dump_traceback()
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raise RuntimeError("timed out while submitting jobs?")
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thread_run = futures.process._ExecutorManagerThread.run
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def mock_run(self):
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# Delay thread startup so the wakeup pipe can fill up and block
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time.sleep(3)
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thread_run(self)
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class MockWakeup(_ThreadWakeup):
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"""Mock wakeup object to force the wakeup to block"""
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def __init__(self):
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super().__init__()
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self._dummy_queue = queue.Queue(maxsize=1)
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def wakeup(self):
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self._dummy_queue.put(None, block=True)
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super().wakeup()
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def clear(self):
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super().clear()
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try:
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while True:
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self._dummy_queue.get_nowait()
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except queue.Empty:
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pass
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with (unittest.mock.patch.object(futures.process._ExecutorManagerThread,
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'run', mock_run),
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unittest.mock.patch('concurrent.futures.process._ThreadWakeup',
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MockWakeup)):
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with self.executor_type(max_workers=2,
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mp_context=self.get_context()) as executor:
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self.executor = executor # Allow clean up in fail_on_deadlock
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job_num = 100
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job_data = range(job_num)
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# Need to use sigalarm for timeout detection because
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# Executor.submit is not guarded by any timeout (both
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# self._work_ids.put(self._queue_count) and
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# self._executor_manager_thread_wakeup.wakeup() might
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# timeout, maybe more?). In this specific case it was
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# the wakeup call that deadlocked on a blocking pipe.
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old_handler = signal.signal(signal.SIGALRM, timeout)
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try:
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signal.alarm(int(self.TIMEOUT))
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self.assertEqual(job_num, len(list(executor.map(int, job_data))))
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finally:
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signal.alarm(0)
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signal.signal(signal.SIGALRM, old_handler)
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create_executor_tests(globals(), ExecutorDeadlockTest,
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executor_mixins=(ProcessPoolForkMixin,
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ProcessPoolForkserverMixin,
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ProcessPoolSpawnMixin))
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def setUpModule():
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setup_module()
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if __name__ == "__main__":
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unittest.main()
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