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GeezerVison is showing github.com — gh-104341: Fix threading Module Shutdown by ericsnowcurrently · Pull Request #104560 · python/cpython

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@ericsnowcurrently

@ericsnowcurrently ericsnowcurrently commented May 16, 2023 •
edited by bedevere-bot
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This should fix the frequent crashes in test_threading and test__xxsubinterpreters.

There is some duplication with the threading module which could be removed after this lands. We can also eliminate PyThreadState.on_delete and PyInterpreterState.threads.count, both of which are cases where the state of the threading module leaked out into the runtime.

(Also see gh-63008 and gh-18296.)

  • Issue: test__xxsubinterpreters is Occasionally Crashing #104341

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ericsnowcurrently added 6 commits May 16, 2023 11:02
@ericsnowcurrently
Add module-owned threads to module state.
e5804c1
@ericsnowcurrently
Re-initialize the module threads lock upon fork.
62df3e6
@ericsnowcurrently
Add module_thread.daemonic.
1bf707f
@ericsnowcurrently
Add module_thread.lifetime_mutex.
da78235
@ericsnowcurrently
Add _thread._wait_for_threads_fini().
ad9bbce
@ericsnowcurrently
Wait for all the threads to finalize.
54dc3b5
@ericsnowcurrently ericsnowcurrently added the skip news label May 16, 2023
@bedevere-bot bedevere-bot added the awaiting core review label May 16, 2023
@bedevere-bot bedevere-bot mentioned this pull request May 16, 2023
test__xxsubinterpreters is Occasionally Crashing #104341
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ericsnowcurrently
ericsnowcurrently commented May 16, 2023
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Comment thread Modules/_threadmodule.c Outdated
Comment on lines +86 to +92
PyThread_acquire_lock(threads->mutex, WAIT_LOCK);
while (threads->head != NULL) {
PyThread_release_lock(threads->mutex);
// XXX Sleep?
PyThread_acquire_lock(threads->mutex, WAIT_LOCK);
}
PyThread_release_lock(threads->mutex);

@ericsnowcurrently ericsnowcurrently May 16, 2023

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FYI, this doesn't feel right. I'm going to look at what my options are. A condvar would work, but that doesn't seem to be something we do in CPython outside the GIL.

(I'm also open to ideas.)

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@ericsnowcurrently ericsnowcurrently May 16, 2023

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I've come up with a slightly better approach.

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@ericsnowcurrently
ericsnowcurrently requested review from markshannon, pitrou and tim-one May 16, 2023 19:34
ericsnowcurrently added 3 commits May 16, 2023 13:39
@ericsnowcurrently
Fix Windows.
b15fa9d
@ericsnowcurrently
Fix Windows.
c7a832b
@ericsnowcurrently
Fix Windows.
51d960e
@ericsnowcurrently ericsnowcurrently added the 🔨 test-with-buildbots Test PR w/ buildbots; report in status section label May 16, 2023
@bedevere-bot

bedevere-bot commented May 16, 2023

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🤖 New build scheduled with the buildbot fleet by @ericsnowcurrently for commit 51d960e 🤖

If you want to schedule another build, you need to add the 🔨 test-with-buildbots label again.
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@bedevere-bot bedevere-bot removed the 🔨 test-with-buildbots Test PR w/ buildbots; report in status section label May 16, 2023
@ericsnowcurrently
Wait for all threads that aren't killed daemon threads to finalize.
bddfc46
adr26
adr26 reviewed May 16, 2023
View reviewed changes
Comment thread Modules/_threadmodule.c Outdated
static struct PyModuleDef thread_module;


/* threads owned by the modulo */

@adr26 adr26 May 16, 2023

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typo: module?

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@ericsnowcurrently ericsnowcurrently May 16, 2023

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fixed

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ericsnowcurrently added 2 commits May 16, 2023 16:31
@ericsnowcurrently
Fix a typo.
188d141
@ericsnowcurrently
Silence some warnings.
bd3accd
@ericsnowcurrently

ericsnowcurrently commented May 17, 2023

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FTR, I ran the buildbots on commit 51d960e: https://buildbot.python.org/all/#/changes/22637.
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@ericsnowcurrently

ericsnowcurrently commented May 17, 2023 •
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Based on CI and the buildbots, I'm thinking there may be something wrong with this PR on macOS. I'll take a look.

Run failed when multiple fork-related tests timed out:

  • https://github.com/python/cpython/actions/runs/4996253064/jobs/8949214929 (commit 51d960e)
  • https://github.com/python/cpython/actions/runs/4997616864/jobs/8952165246 (commit bd3accd)
  • https://buildbot.python.org/all/#/builders/721/builds/1163/steps/5/logs/stdio ("ARM64 macOS PR")

On the "x86-64 macOS PR" builder, the run was cancelled 3 times:

  • https://buildbot.python.org/all/#/builders/311/builds/1311
  • https://buildbot.python.org/all/#/builders/311/builds/1310
  • https://buildbot.python.org/all/#/builders/311/builds/1309
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@ericsnowcurrently

ericsnowcurrently commented May 17, 2023 •
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CI run 1

(https://github.com/python/cpython/actions/runs/4996253064/jobs/8949214929)

12 test modules failed before the CI job was canceled.

(details)

test module timed out after 20 minutes (1200s):

  • test_multiprocessing_main_handling (test_directory_compiled)
  • test_httpservers (test_accept)
  • test_fork1 (test_wait in fork_wait.py)
  • test_thread (test_forkinthread)
  • test_socketserver (test_forking_handled)
  • test_asyncio (test_fork_asyncio_run)
  • test_os (test_fork_warns_when_non_python_thread_exists)

individual tests timed out:

  • test.fork_wait.ForkWait.test_wait, via test_wait4 (300s)
  • test.test_wait4.Wait4Test.test_wait (30s)
  • test.test_tracemalloc.TestTracemallocEnabled.test_fork (300s)
  • test.test_pty.PtyTest.test_fork
  • test.test_pty.PtyTest.test_spawn_doesnt_hang
  • test.test_uuid.TestUUIDWithExtModule.testIssue8621 (300s)
  • test.test_uuid.TestUUIDWithoutExtModule.testIssue8621 (300s)
  • test.test_support.TestSupport.test_reap_children (30s)
  • test.test_support.TestSupport.test_temp_dir__forked_child (300s)

still running:

  • test_mailbox
  • test_wait3
  • test_tempfile
  • test_random

CI run 2

(https://github.com/python/cpython/actions/runs/4997616864/jobs/8952165246)

12 test modules failed before the CI job was canceled.

(details)

test module timed out after 20 minutes (1200s):

  • test_thread (test_forkinthread)
  • test_subprocess (test_close_fds_after_preexec)
  • test_concurrent_futures (tearDown)
  • test_builtin (test_input_no_stdout_fileno)
  • test_socketserver (test_forking_handled)
  • test_httpservers (test_accept)
  • test.test_asyncio.test_unix_events (test_fork_asyncio_run)

individual tests timed out:

  • test.fork_wait.ForkWait.test_wait, via test_wait3 (300s)
  • test.test_wait3.Wait3Test.test_wait (30s)
  • test.test_uuid.TestUUIDWithExtModule.testIssue8621 (300s)
  • test.test_uuid.TestUUIDWithoutExtModule.testIssue8621 (300s)
  • test.fork_wait.ForkWait.test_wait, via test_wait4 (300s)
  • test.test_wait4.Wait4Test.test_wait (30s)
  • test.test_pty.PtyTest.test_fork
  • test.test_logging.HandlerTest.test_post_fork_child_no_deadlock (300s)

still running:

  • test_multiprocessing_spawn
  • test_multiprocessing_main_handling
  • test_os
  • test_tempfile

Buildbot (ARM64 macOS PR)

(https://buildbot.python.org/all/#/builders/721/builds/1163/steps/5/logs/stdio)

25 test modules failed

(details)

test module timed out after 15 minutes (900s):

  • test_httpservers (test_accept)
  • test_threading (test_clear_threads_states_after_fork)
  • test_fork1 (test_wait in fork_wait.py)
  • test_concurrent_futures (test_duplicate_futures)
  • test_multiprocessing_spawn (test_context)
  • test_tempfile (test_noinherit)
  • test_socketserver (test_forking_handled)
  • test_os (test_fork_warns_when_non_python_thread_exists)
  • test_mailbox (test_lock_conflict)
  • test_subprocess (test_close_fds_after_preexec)
  • test_thread (test_forkinthread)
  • test.test_asyncio.test_unix_events (test_fork_asyncio_run)
  • test_multiprocessing_main_handling (test_directory)
  • test_builtin (test_input_no_stdout_fileno)
  • test_cmd_line (test_no_std_streams)
  • test_random (test_after_fork)
  • test_multiprocessing_forkserver (test_closefd)

individual tests timed out:

  • test.test_tracemalloc.TestTracemallocEnabled.test_fork (300s)
  • test.fork_wait.ForkWait.test_wait, via test_wait4 (300s)
  • test.test_wait4.Wait4Test.test_wait (30s)
  • test.test_support.TestSupport.test_reap_children (30s)
  • test.test_support.TestSupport.test_temp_dir__forked_child (300s)
  • test.fork_wait.ForkWait.test_wait, via test_wait3 (300s)
  • test.test_wait3.Wait3Test.test_wait (30s)
  • test.test_platform.PlatformTest.test_mac_ver_with_fork (300s)
  • test.test_pty.PtyTest.test_fork
  • test.test_pty.PtyTest.test_spawn_doesnt_hang
  • test.test_logging.HandlerTest.test_post_fork_child_no_deadlock (300s)
  • test.test_uuid.TestUUIDWithExtModule.testIssue8621 (300s)
  • test.test_uuid.TestUUIDWithoutExtModule.testIssue8621 (300s)
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@arhadthedev

arhadthedev commented May 17, 2023 •
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I reran the job and got the same result (the tests are not done yet but started to time out already).
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@ericsnowcurrently
ericsnowcurrently marked this pull request as draft May 18, 2023 16:57
@bedevere-bot bedevere-bot removed the awaiting core review label May 18, 2023
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github-actions Bot commented Apr 13, 2026

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This PR is stale because it has been open for 30 days with no activity.
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@github-actions github-actions Bot added the stale Stale PR or inactive for long period of time. label Apr 13, 2026
@ambv

ambv commented Oct 20, 2026

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This PR is attached to gh-104341, which is already completed: the fix for that issue landed through other changes, and this PR's approach was not taken or has since become obsolete. Closing to cull the number of open pull requests. Do not reopen this pull request without getting a go-ahead from a triager or core developer.
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@ambv ambv closed this Oct 20, 2026
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@pitrou pitrou Awaiting requested review from pitrou
@tim-one tim-one Awaiting requested review from tim-one
@markshannon markshannon Awaiting requested review from markshannon
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@ericsnowcurrently @bedevere-bot @arhadthedev @ambv @adr26
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