Avoid ctypes callbacks when listing libraries on Linux. - #242
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Importing ctypes.util or using CFUNCTYPE with dl_iterate_phdr creates libffi closures that can abort after fork on some Linux libffi builds. Enumerate libraries from /proc/self/maps and load libc via CDLL(None). Co-authored-by: Cursor <cursoragent@cursor.com>
joblib#243 already lists libraries from /proc/self/maps. Keep that path and only avoid importing ctypes.util (load libc via CDLL(None), lazy-import dllist off Linux) so the libffi abort after fork from joblib#225 stays fixed. Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
ogrisel
commented
Sep 14, 2026
Bind dllist to None on Linux instead of importing ctypes.util, so _find_libraries_with_python can stay a void finder and the 3.14 branch of _load_libraries does not have to use a boolean return as control flow. Co-authored-by: Olivier Grisel <olivier.grisel@ensta.org>
Keep the finder a void helper by passing the imported dllist callable, and still skip ctypes.util entirely on Linux and emscripten. Co-authored-by: Olivier Grisel <olivier.grisel@ensta.org>
…allbacks-linux Keep dllist imported in _load_libraries and pass it to _find_libraries_with_python, while taking master's OSError warning when dllist listing fails. Co-authored-by: Olivier Grisel <olivier.grisel@ensta.org>
ogrisel
marked this pull request as ready for review
September 15, 2026 13:57
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I think the extra code complexity is fine, let's merge. |
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Workaround for #225 on some system:
Importing ctypes.util or using CFUNCTYPE with dl_iterate_phdr creates libffi closures that can abort after fork on some Linux libffi builds. Enumerate libraries from /proc/self/maps and load libc via CDLL(None).
Disclaimer: this PR was vibecoded although I did ask the agent to use a container to check that it actually workaround the problem on AlmaLinux 9.8 (Olive Jaguar) with libffi-3.4.2-8.el9.
Still, I find the extra complexity in threadpoolctl not justified. I would rather wait for upstream ctypes to fix the problem or wait for all impacted linux distributions to upgrade to a newer libffi.