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Memory leak in test_capi with subinterpreter creation #140301

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Memory leak in test_capi with subinterpreter creation#140301
Labels
testsTests in the Lib/test dirtopic-C-APItopic-subinterpreterstype-bugAn unexpected behavior, bug, or error

Description

@ashm-dev
ashm-dev
opened on Oct 18, 2025

Bug report

Bug description:

LeakSanitizer detects memory leaks when running test_capi with refleak detection. The leaks occur during subinterpreter creation via Py_NewInterpreterFromConfig().

Affected Versions

  • Python 3.12
  • Python 3.13
  • Python 3.14
  • CPython main branch

Steps to Reproduce

  1. Build CPython with AddressSanitizer and debug mode:
CC=clang CXX=clang++ ./configure --with-address-sanitizer --with-pydebug --with-undefined-behavior-sanitizer --disable-optimizations && make -j$(nproc)
  1. Run test_capi with refleak detection:
./python -X dev -X showrefcount -m test -R 5:5 test_capi -j$(nproc)

Logs

312.log
313.log
314.log
main.log

CPython versions tested on:

3.15, CPython main branch, 3.14, 3.13, 3.12

Operating systems tested on:

Linux

Linked PRs

Activity

  1. ashm-dev
    added
    type-bugAn unexpected behavior, bug, or error
    on Oct 18, 2025
  2. StanFromIreland
    added
    performancePerformance or resource usage
    testsTests in the Lib/test dir
    topic-C-API
    on Oct 18, 2025
  3. ZeroIntensity
    removed
    performancePerformance or resource usage
    on Oct 18, 2025

  4. ZeroIntensity commented on Oct 18, 2025

    @ZeroIntensity
    ZeroIntensity
    on Oct 18, 2025
    Member

    In the future, would you mind including locations (preferably a GitHub source link) in your reports? It's extra work for us when you just drop large log files.

  5. ZeroIntensity
    added
    topic-subinterpreters
    on Oct 18, 2025
  6. github-project-automation
    moved this to Todo in Subinterpreterson Oct 18, 2025
  7. github-project-automation
    added this to Subinterpreterson Oct 18, 2025

  8. ashm-dev commented on Oct 18, 2025

    @ashm-dev
    ashm-dev
    on Oct 18, 2025
    ContributorAuthor

    Sure, I'll include GitHub source links in future reports. Thanks for the feedback!

  9. ashm-dev commented on Oct 18, 2025

    @ashm-dev
    ashm-dev
    on Oct 18, 2025
    ContributorAuthor

    I'll take a shot at fixing this, but no promises :)

  10. ashm-dev
    added a commit that references this issue on Oct 18, 2025

    pythongh-140301: Fix memory leak in subinterpreter PyConfig cleanup

    4adb87e
  11. kumaraditya303
    added a commit that references this issue on Oct 20, 2025

    gh-140301: Fix memory leak in subinterpreter `PyConfig` cleanup (#140303

    a615fb4
  12. miss-islington
    added a commit that references this issue on Oct 20, 2025

    pythongh-140301: Fix memory leak in subinterpreter `PyConfig` cleanup (…

    9d293ea
  13. kumaraditya303
    closed this as completedon Oct 20, 2025
  14. github-project-automation
    moved this from Todo to Done in Subinterpreterson Oct 20, 2025
  15. kumaraditya303
    added a commit that references this issue on Oct 20, 2025

    [3.14] gh-140301: Fix memory leak in subinterpreter `PyConfig` cleanup (

    d7fe4e9
  16. ashm-dev
    added 3 commits that reference this issue on Oct 27, 2025

    pythongh-140301: Fix memory leak in subinterpreter `PyConfig` cleanup (…

    c38ad5e

    [3.13] pythongh-140301: Fix memory leak in subinterpreter PyConfig cl…

    affa9be

    [3.13] pythongh-140301: Fix memory leak in subinterpreter `PyConfig` …

    6adce9a
  17. kumaraditya303
    added a commit that references this issue on Oct 27, 2025

    [3.13] gh-140301: Fix memory leak in subinterpreter PyConfig cleanup (G…

    fd6df66
  18. StanFromIreland
    added a commit that references this issue on Dec 6, 2025

    pythongh-140301: Fix memory leak in subinterpreter `PyConfig` cleanup (…

    459785b
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