gh-101225: Increase the socket backlog when creating a multiprocessing.connection.Listener (GH-113567)
Increase the backlog for multiprocessing.connection.Listener` objects created
by `multiprocessing.manager` and `multiprocessing.resource_sharer` to
significantly reduce the risk of getting a connection refused error when creating
a `multiprocessing.connection.Connection` to them.
(cherry picked from commit c7d59bd8cf)
Co-authored-by: Ronald Oussoren <ronaldoussoren@mac.com>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
gh-113009: Fix multiprocessing Process.terminate() on Windows (GH-113128)
On Windows, Process.terminate() no longer sets the returncode
attribute to always call WaitForSingleObject() in Process.wait().
Previously, sometimes the process was still running after
TerminateProcess() even if GetExitCodeProcess() is not STILL_ACTIVE.
(cherry picked from commit 4026ad5b2c)
Co-authored-by: Victor Stinner <vstinner@python.org>
gh-110036: multiprocessing Popen.terminate() catches PermissionError (GH-110037)
On Windows, multiprocessing Popen.terminate() now catchs
PermissionError and get the process exit code. If the process is
still running, raise again the PermissionError. Otherwise, the
process terminated as expected: store its exit code.
(cherry picked from commit bd4518c60c)
Co-authored-by: Victor Stinner <vstinner@python.org>
Follow-up of gh-107219.
* Only close the connection writer on Windows.
* Also use existing constant _winapi.ERROR_OPERATION_ABORTED instead of
WSA_OPERATION_ABORTED.
(cherry picked from commit 0b4e090422)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
gh-107219: Fix concurrent.futures terminate_broken() (GH-109244)
Fix a race condition in concurrent.futures. When a process in the
process pool was terminated abruptly (while the future was running or
pending), close the connection write end. If the call queue is
blocked on sending bytes to a worker process, closing the connection
write end interrupts the send, so the queue can be closed.
Changes:
* _ExecutorManagerThread.terminate_broken() now closes
call_queue._writer.
* multiprocessing PipeConnection.close() now interrupts
WaitForMultipleObjects() in _send_bytes() by cancelling the
overlapped operation.
(cherry picked from commit a9b1f84790)
Co-authored-by: Victor Stinner <vstinner@python.org>
gh-107275 introduced a regression where a SemLock would fail being passed along nested child processes, as the `is_fork_ctx` attribute would be left missing after the first deserialization.
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(cherry picked from commit add8d45cbe)
Co-authored-by: albanD <desmaison.alban@gmail.com>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Antoine Pitrou <pitrou@free.fr>
gh-77377: Ensure multiprocessing SemLock is valid for spawn-based Process before serializing it (GH-107275)
Ensure multiprocessing SemLock is valid for spawn Process before serializing it.
Creating a multiprocessing SemLock with a fork context, and then trying to pass it to a spawn-created Process, would segfault if not detected early.
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(cherry picked from commit 1700d34d31)
Co-authored-by: albanD <desmaison.alban@gmail.com>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Antoine Pitrou <pitrou@free.fr>
gh-107963: Fix set_forkserver_preload to check the type of given list (GH-107965)
(cherry picked from commit 6515ec3d3d)
gh-107963: Fix set_forkserver_preload to check the type of given list
Co-authored-by: Dong-hee Na <donghee.na@python.org>
gh-90876: Restore the ability to import multiprocessing when `sys.executable` is `None` (GH-106464)
Prevent `multiprocessing.spawn` from failing to *import* in environments
where `sys.executable` is `None`. This regressed in 3.11 with the addition
of support for path-like objects in multiprocessing.
Adds a test decorator to have tests only run when part of test_multiprocessing_spawn to `_test_multiprocessing.py` so we can start to avoid re-running the same not-global-state specific test in all 3 modes when there is no need.
(cherry picked from commit c60df361ce)
Co-authored-by: Gregory P. Smith <greg@krypto.org>
Fix a race condition in the internal `multiprocessing.process` cleanup
logic that could manifest as an unintended `AttributeError` when calling
`BaseProcess.close()`.
(cherry picked from commit ef5d00a592)
Co-authored-by: Luccccifer <lukezhang764@gmail.com>
Co-authored-by: Oleg Iarygin <oleg@arhadthedev.net>
Co-authored-by: Gregory P. Smith <greg@krypto.org>
bpo-40882: Fix a memory leak in SharedMemory on Windows (GH-20684)
In multiprocessing.shared_memory.SharedMemory(), the temporary view
returned by MapViewOfFile() should be unmapped when it is no longer
needed.
(cherry picked from commit 85c128e34d)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>
Linux abstract sockets are insecure as they lack any form of filesystem
permissions so their use allows anyone on the system to inject code into
the process.
This removes the default preference for abstract sockets in
multiprocessing introduced in Python 3.9+ via
https://github.com/python/cpython/pull/18866 while fixing
https://github.com/python/cpython/issues/84031.
Explicit use of an abstract socket by a user now generates a
RuntimeWarning. If we choose to keep this warning, it should be
backported to the 3.7 and 3.8 branches.
(cherry picked from commit 49f61068f4)
Co-authored-by: Gregory P. Smith <greg@krypto.org>
Automerge-Triggered-By: GH:gpshead
SharedMemory.unlink() uses the unregister() function from resource_tracker. Previously it was imported in the method, but this can fail if the method is called during interpreter shutdown, for example when unlink is part of a __del__() method.
Moving the import to the top of the file, means that the unregister() method is available during interpreter shutdown.
The register call in SharedMemory.__init__() can also use this imported resource_tracker.
(cherry picked from commit 9a458befdd)
Co-authored-by: samtygier <samtygier@yahoo.co.uk>
One more thing that can help prevent people from using `preexec_fn`.
Also adds conditional skips to two tests exposing ASAN flakiness on the Ubuntu 20.04 Address Sanitizer Github CI system. When that build is run on more modern systems the "problem" does not show up. It seems ASAN implementation related.
Co-authored-by: Zackery Spytz <zspytz@gmail.com>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Just in case there is ever an issue with _posixsubprocess's use of
vfork() due to the complexity of using it properly and potential
directions that Linux platforms where it defaults to on could take, this
adds a failsafe so that users can disable its use entirely by setting
a global flag.
No known reason to disable it exists. But it'd be a shame to encounter
one and not be able to use CPython without patching and rebuilding it.
See the linked issue for some discussion on reasoning.
Also documents the existing way to disable posix_spawn.
Add an optional keyword 'shutdown_timeout' parameter to the
multiprocessing.BaseManager constructor. Kill the process if
terminate() takes longer than the timeout.
Multiprocessing tests pass test.support.SHORT_TIMEOUT
to BaseManager.shutdown_timeout.
This was causing test___all__ to fail on platforms lacking a shared
memory implementation.
Co-Authored-By: Xavier de Gaye <xdegaye@gmail.com>
Co-authored-by: Łukasz Langa <lukasz@langa.pl>
The multiprocessing Server class now explicitly catchs SystemExit and
closes the client connection in this case. It happens when the
Server.serve_client() method reachs the end of file (EOF).
In the case of multiprocessing.synchronize() being missing, the
test_concurrent_futures test suite now skips only the tests that
require multiprocessing.synchronize().
Validate that multiprocessing.synchronize exists as part of
_check_system_limits(), allowing ProcessPoolExecutor to raise
NotImplementedError during __init__, rather than crashing with
ImportError during __init__ when creating a lock imported from
multiprocessing.synchronize.
Use _check_system_limits() to disable tests of
ProcessPoolExecutor on systems without multiprocessing.synchronize.
Running the test suite without multiprocessing.synchronize reveals
that Lib/compileall.py crashes when it uses a ProcessPoolExecutor.
Therefore, change Lib/compileall.py to call _check_system_limits()
before creating the ProcessPoolExecutor.
Note that both Lib/compileall.py and Lib/test/test_compileall.py
were attempting to sanity-check ProcessPoolExecutor by expecting
ImportError. In multiprocessing.resource_tracker, sem_unlink() is also absent
on platforms where POSIX semaphores aren't available. Avoid using
sem_unlink() if it, too, does not exist.
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
Avoid linear runtime of ShareableList.__getitem__ and
ShareableList.__setitem__ by storing running allocated bytes in
ShareableList._allocated_bytes instead of the number of bytes for
a particular stored item.
Co-authored-by: Antoine Pitrou <antoine@python.org>
Add os.waitstatus_to_exitcode() function to convert a wait status to an
exitcode.
Suggest waitstatus_to_exitcode() usage in the documentation when
appropriate.
Use waitstatus_to_exitcode() in:
* multiprocessing, os, subprocess and _bootsubprocess modules;
* test.support.wait_process();
* setup.py: run_command();
* and many tests.
When the pull is not used via the context manager or terminate() is called, there is a system in multiprocessing.util that handles finalization of all pools via an atexit handler (the Finalize) class. This class registers the _terminate_pool handler in the registry of finalizers of the module, and that registry is called on interpreter exit via _exit_function. The problem is that the "happy" path with the context manager or manual call to finalize() does some extra steps that _terminate_pool does not. The step that is not executed when the atexit() handler calls _terminate_pool is pinging the _change_notifier queue to unblock the maintenance threads.
This commit moves the notification to the _terminate_pool function so is called from both code paths.
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
Miss Islington (bot)