Created on 2021-11-17 21:57 by colesbury, last changed 2021-11-18 16:21 by lukasz.langa. This issue is now closed.
| Files | ||||
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| File name | Uploaded | Description | Edit | |
| issue45835_repro.patch | colesbury, 2021-11-17 21:59 | |||
| Pull Requests | |||
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| URL | Status | Linked | Edit |
| PR 29601 | merged | colesbury, 2021-11-17 22:29 | |
| PR 29612 | merged | miss-islington, 2021-11-18 08:51 | |
| PR 29613 | merged | miss-islington, 2021-11-18 08:51 | |
| Messages (5) | |||
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| msg406498 - (view) | Author: Sam Gross (colesbury) *  |
Date: 2021-11-17 21:57 | |
The test_queue suite has a race condition that can lead to test failures in test_many_threads, test_many_threads_nonblock, and test_many_threads_timeout. Consumers are signaled to exit by a sentinel value (None). The sentinel values are at the end of the input list, but that doesn't mean they are necessarily enqueued at the end of the inter-thread queue when there are multiple "feeder" threads. In particular, a feeder thread may be delayed in enqueueing a non-sentinel value. The other feeder threads may finish popping and enqueueing the remaining values including all the sentinels, leading to the delayed non-sentinel value arriving AFTER all the sentinels. The "consumer" threads exit before processing all the values leading to the assertion error in run_threads() in test_queue.py: self.assertTrue(q.empty()) I will attach a patch that adds a delay in feed() to make the race condition occur more frequently so that the issue is easier to reproduce. |
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| msg406521 - (view) | Author: Antoine Pitrou (pitrou) *  |
Date: 2021-11-18 08:51 | |
New changeset df3e53d86b2ad67da9ac2b5a3f56257d1f394982 by Sam Gross in branch 'main': bpo-45835: Fix race condition in test_queue (#29601) https://github.com/python/cpython/commit/df3e53d86b2ad67da9ac2b5a3f56257d1f394982 |
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| msg406545 - (view) | Author: Łukasz Langa (lukasz.langa) * |
Date: 2021-11-18 16:05 | |
New changeset 5cf05c71d13a4b4a94cc77da4214ee2f0b9c7de7 by Miss Islington (bot) in branch '3.10': bpo-45835: Fix race condition in test_queue (GH-29601) (GH-29612) https://github.com/python/cpython/commit/5cf05c71d13a4b4a94cc77da4214ee2f0b9c7de7 |
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| msg406550 - (view) | Author: miss-islington (miss-islington) | Date: 2021-11-18 16:16 | |
New changeset 9450c751cc2053b1c2e03ec92ed822a41223b142 by Miss Islington (bot) in branch '3.9': bpo-45835: Fix race condition in test_queue (GH-29601) https://github.com/python/cpython/commit/9450c751cc2053b1c2e03ec92ed822a41223b142 |
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| msg406553 - (view) | Author: Łukasz Langa (lukasz.langa) * |
Date: 2021-11-18 16:21 | |
Thanks, Sam! ✨ 🍰 ✨ |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2021-11-18 16:21:05 | lukasz.langa | set | status: open -> closed resolution: fixed messages: + msg406553 stage: patch review -> resolved |
| 2021-11-18 16:16:20 | miss-islington | set | messages: + msg406550 |
| 2021-11-18 16:05:49 | lukasz.langa | set | nosy:
+ lukasz.langa messages: + msg406545 |
| 2021-11-18 08:51:46 | miss-islington | set | pull_requests: + pull_request27849 |
| 2021-11-18 08:51:41 | miss-islington | set | nosy:
+ miss-islington pull_requests: + pull_request27848 |
| 2021-11-18 08:51:34 | pitrou | set | nosy:
+ pitrou messages: + msg406521 |
| 2021-11-17 22:29:03 | colesbury | set | stage: patch review pull_requests: + pull_request27844 |
| 2021-11-17 21:59:50 | colesbury | set | files:
+ issue45835_repro.patch keywords: + patch |
| 2021-11-17 21:57:20 | colesbury | create | |