gh-142534: Avoid TSan warnings in dictobject.c#142544
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colesbury merged 3 commits intopython:mainfrom Dec 11, 2025
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There are places we use "relaxed" loads where C11 requires "consume" or stronger. Unfortunately, compilers don't really implement "consume" so fake it for our use in a way that avoids upsetting TSan.
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@DinoV - with this PR, I no longer get warnings for |
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Yeah, I think that makes sense. |
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I've confirmed this fixes the issues on the lazy imports branch w/ the object.c and unicodeobject.c changes in this diff backed out: https://fb.workplace.com/chat/t/6551713648259080#:~:text=https%3A//github.com/LazyImportsCabal/cpython/commit/470b9e436222ef099c86dde640ea739acf0d5456 |
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Thanks @colesbury for the PR 🌮🎉.. I'm working now to backport this PR to: 3.14. |
miss-islington
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Dec 11, 2025
There are places we use "relaxed" loads where C11 requires "consume" or stronger. Unfortunately, compilers don't really implement "consume" so fake it for our use in a way that avoids upsetting TSan. (cherry picked from commit 0a62f82) Co-authored-by: Sam Gross <colesbury@gmail.com>
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GH-142603 is a backport of this pull request to the 3.14 branch. |
fatelei
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There are places we use "relaxed" loads where C11 requires "consume" or stronger. Unfortunately, compilers don't really implement "consume" so fake it for our use in a way that avoids upsetting TSan.
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Feb 18, 2026
Summary: Building wheels is broken right now because cibuildwheel is using a docker container with Python 3.14.2, but our borrowed file now expects Python 3.14.3. See https://github.com/facebookincubator/cinderx/actions/runs/22123173632/job/63947574316 as what an example failure here looks like, the build is complaining about something that was fixed in python/cpython#142544 and landed in Python 3.14.3. There's no great way to map Python version to manylinux docker container version. Claude tells me this is how we would switch to using the latest one. This is a bit of a mess... Reviewed By: yoney Differential Revision: D93613525 fbshipit-source-id: 4531f7dda97ebc3e4f6880154f0fc3c3456f7ab8
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Feb 21, 2026
Summary: FT_ATOMIC_LOAD_PTR_CONSUME was added in 3.14.3. When we try to build CinderX for 3.14.2, it breaks because this isn't defined. Follow what the original PR was doing and define it to acquire semantics, which are stronger than consume. See python/cpython#142544 that added this. Reviewed By: yoney Differential Revision: D93925688 fbshipit-source-id: f032caaed424b0f6e883d61627664a8bbd1c5379
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There are places we use "relaxed" loads where C11 requires "consume" or stronger. Unfortunately, compilers don't really implement "consume" so fake it for our use in a way that avoids upsetting TSan.