gh-146527: Fix memory leak in _PyGC_Fini() - #150969
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vstinner merged 2 commits intoJun 5, 2026
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Free generation_stats allocated by _PyGC_Init(). Fix Python/gc.c: Python/gc_free_threading.c was already fixed.
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For example, the leak can be seen with Valgrind. $ PYTHONMALLOC=malloc valgrind --leak-check=full --show-leak-kinds=all --num-callers=20 ./python -c pass (...) ==3201846== HEAP SUMMARY: ==3201846== in use at exit: 1,112 bytes in 1 blocks ==3201846== total heap usage: 28,765 allocs, 28,764 frees, 6,620,982 bytes allocated ==3201846== ==3201846== 1,112 bytes in 1 blocks are still reachable in loss record 1 of 1 ==3201846== at 0x484862B: calloc (vg_replace_malloc.c:1616) ==3201846== by 0x4FE115: _PyMem_RawCalloc (obmalloc.c:80) ==3201846== by 0x511FC1: PyMem_RawCalloc (obmalloc.c:1222) ==3201846== by 0x62A744: _PyGC_Init (gc.c:137) ==3201846== by 0x65DB65: pycore_interp_init (pylifecycle.c:975) ==3201846== by 0x65DD71: pyinit_config (pylifecycle.c:1040) ==3201846== by 0x666D3A: pyinit_core (pylifecycle.c:1203) ==3201846== by 0x666E13: Py_InitializeFromConfig (pylifecycle.c:1631) ==3201846== by 0x69888E: pymain_init (main.c:69) ==3201846== by 0x698953: pymain_main (main.c:817) ==3201846== by 0x6989E4: Py_BytesMain (main.c:850) ==3201846== by 0x401CEE: main (python.c:15) ==3201846== ==3201846== LEAK SUMMARY: ==3201846== definitely lost: 0 bytes in 0 blocks ==3201846== indirectly lost: 0 bytes in 0 blocks ==3201846== possibly lost: 0 bytes in 0 blocks ==3201846== still reachable: 1,112 bytes in 1 blocks ==3201846== suppressed: 0 bytes in 0 blocks (...) I found the leak when building Python with ASAN. |
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vstinner
enabled auto-merge (squash)
June 5, 2026 13:13
pablogsal
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Jun 5, 2026
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Thanks victor! |
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Thanks @vstinner for the PR 🌮🎉.. I'm working now to backport this PR to: 3.15. |
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GH-150970 is a backport of this pull request to the 3.15 branch. |
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Thanks! |
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philthompson10
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Jun 17, 2026
Free generation_stats allocated by _PyGC_Init(). Fix Python/gc.c: Python/gc_free_threading.c was already fixed.
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Free generation_stats allocated by _PyGC_Init().
Fix Python/gc.c: Python/gc_free_threading.c was already fixed.