Description

ashm-dev

opened on Oct 18, 2025

Issue body actions

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)

2. 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

• gh-140301: Fix memory leak in subinterpreter PyConfig cleanup #140303
• [3.14] gh-140301: Fix memory leak in subinterpreter PyConfig cleanup (GH-140303) #140360
• [3.13] gh-140301: Fix memory leak in subinterpreter PyConfig cleanup (GH-140303) #140684

Activity

1. ashm-dev

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Oct 18, 2025
2. StanFromIreland

   added

   performancePerformance or resource usagePerformance or resource usage

   testsTests in the Lib/test dirTests in the Lib/test dir

   topic-C-API

   on Oct 18, 2025
3. ZeroIntensity

   removed

   performancePerformance or resource usagePerformance or resource usage

   on Oct 18, 2025
4. ZeroIntensity commented on Oct 18, 2025

   

   ZeroIntensity

   on Oct 18, 2025

   Member

   More actions

   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.

   Reacted by Shamil
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

   on Oct 18, 2025

   ContributorAuthor

   More actions

   Sure, I'll include GitHub source links in future reports. Thanks for the feedback!
9. ashm-dev commented on Oct 18, 2025

   

   ashm-dev

   on Oct 18, 2025

   ContributorAuthor

   More actions

   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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