BUG: fix memory leak in np.zeros when fill-zero loop raises#31320
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seberg
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Apr 25, 2026
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Thanks a lot, looks good to me! (Will hold off merging a moment.)
I guess adding a test that fails during the zero filling is annoying, but your DType tested this (maybe accidentally, so?).
(Our CI now has leak sanitizer running even, but we have no dtype that can be made to fail unless we write one just for this...)
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| fail: | ||
| NPY_traverse_info_xfree(&fill_zero_info); | ||
| Py_XDECREF(fa->mem_handler); |
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Hah, "fun" that the old logic worked out here because the owndata flag wasn't set yet and mem_handler was never deallocated.
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OK, let's put this in, thanks again. |
charris
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Apr 28, 2026
BUG: fix memory leak in np.zeros when fill-zero loop raises
charris
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Apr 28, 2026
BUG: fix memory leak in np.zeros when fill-zero loop raises (#31320)
MaanasArora
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May 7, 2026
BUG: fix memory leak in np.zeros when fill-zero loop raises
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PR summary
This PR fixes a memory leak in np.zeros that occurs when the fill-zero loop raises an exception (which can happen for custom user-defined dtypes). It does this by setting NPY_ARRAY_OWNDATA earlier to ensure the data will be deallocated, combined with changes to mem_handler cleanup to avoid a double-decref.
I'm not entirely sure whether this is the most appropriate way to fix the leak, but it does seem to work correctly based on testing with
tracemalloc.AI Disclosure
The bug was detected through testing with
tracemalloc, then located and fixed by Claude Opus 4.7.Full AI-generated description: https://gist.github.com/MaartenBaert/f3eadd280f84ef6896586025f59788ec