| msg289539 - (view) |
Author: Iryna Shcherbina (ishcherb) * |
Date: 2017-03-13 13:48 |
| I am trying to build Python 3.6.1rc1 on Fedora, and have the following test failing on arm64 (aarch64) architecture: ====================================================================== FAIL: test_pass_by_value (ctypes.test.test_structures.StructureTestCase) ---------------------------------------------------------------------- Traceback (most recent call last): File "/builddir/build/BUILD/Python-3.6.1rc1/Lib/ctypes/test/test_structures.py", line 413, in test_pass_by_value self.assertEqual(s.first, 0xdeadbeef) AssertionError: 195948557 != 3735928559 ---------------------------------------------------------------------- The build log is attached. The test was added in this commit [1] as a fix for bpo-29565. Any idea what this can be related to? [1] https://github.com/python/cpython/commit/3cc5817cfaf5663645f4ee447eaed603d2ad290a |
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| msg289589 - (view) |
Author: Iryna Shcherbina (ishcherb) * |
Date: 2017-03-14 14:23 |
| Hi Vinay, I have added you to the nosy list as you are the author of the fix for bpo-29565, and would like to ask you for insights or ideas on why the test would fail only on one architecture (arm64)? |
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| msg289595 - (view) |
Author: Vinay Sajip (vinay.sajip) *  |
Date: 2017-03-14 15:05 |
| The test checks that a structure passed by value is indeed passed by value - something that is architecture-dependent, as calling conventions differ across architectures. If the test fails, this indicates that the structure isn't being passed by value - a pointer to the structure is probably passed, which is pass-by-reference rather than pass-by-value. This indicates that a change to ctypes or libffi is needed to fix this. See the changes made in Modules/_ctypes/libffi_msvc/ffi.c for bpo-29565 - probably, analogous changes need to be made to the corresponding code for arm64. |
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| msg289669 - (view) |
Author: Charalampos Stratakis (cstratak) * |
Date: 2017-03-15 12:29 |
| Since this newly added assertion [0] fails for aarch64 shouldn't this be considered a regression? And taking into account the timeframe, a release blocker for 3.6.1? |
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| msg289670 - (view) |
Author: Charalampos Stratakis (cstratak) * |
Date: 2017-03-15 12:29 |
| [0] https://github.com/python/cpython/commit/a86339b83fbd0932e0529a3c91935e997a234582#diff-39e8978a35ab16f78e60027c61b810f7R413 |
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| msg289674 - (view) |
Author: Vinay Sajip (vinay.sajip) * |
Date: 2017-03-15 13:32 |
| I don't think it's a regression. It's catching an error that was there, but wasn't tested for before. If it should be a release blocker - that should not be for any reversion of the change to the test, but for implementing the pass-by-value functionality correctly. |
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| msg290065 - (view) |
Author: Ned Deily (ned.deily) * |
Date: 2017-03-23 22:40 |
| Technically speaking, we do not officially support arm64 in our release process as we have no arm64 buildbots nor an identified core developer for the platform; see PEP 11 for the policy details. So there is no place to test a fix if there was one identified. That said, it would be good to fix the problem if someone is willing to provide a fix and test it or determine that the issue here is a libffi problem. It would be even better if we could make arm64 an officially supported platform as outlined. |
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| msg312200 - (view) |
Author: Iryna Shcherbina (ishcherb) * |
Date: 2018-02-15 11:00 |
| PR 1559 fixes the issue in Fedora builds on arm64. The issue is no longer reproducible with Python 3.7. |
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| msg312963 - (view) |
Author: Ned Deily (ned.deily) * |
Date: 2018-02-26 21:53 |
| Vinay, should this backported to 3.6? Otherwise, can the issue be closed? |
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| msg312964 - (view) |
Author: Charalampos Stratakis (cstratak) * |
Date: 2018-02-26 22:02 |
| The bug is still present on the 3.6 branch. |
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| msg312982 - (view) |
Author: Vinay Sajip (vinay.sajip) * |
Date: 2018-02-27 08:48 |
| > Vinay, should this back-ported to 3.6? Yes, I think it should be. |
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| msg313625 - (view) |
Author: Ned Deily (ned.deily) * |
Date: 2018-03-11 22:20 |
| OK, PR 1559 (in 3.7.0) for Issue30353 has been backported to 3.6 in PR 5954 for release in 3.6.5. So based on , I'm going to assume the problem is no longer reproducible in 3.6 and close this issue. If not, please reopen. |
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| msg322956 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2018-08-02 14:05 |
| This issue is mentioned from https://bugzilla.redhat.com/show_bug.cgi?id=1336557 but it seems like the bug has not been fixed in Python 2.7. I created PR 8625 to backport the fix to Python 2.7. |
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| msg322964 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2018-08-02 14:48 |
| New changeset 3243f8c1fb16b6de73f1d7a30f5d09047553bce3 by Victor Stinner in branch '2.7': bpo-29565: Corrected ctypes passing of large structs by value on Windows AMD64 (GH-168) (GH-8625) https://github.com/python/cpython/commit/3243f8c1fb16b6de73f1d7a30f5d09047553bce3 |
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| msg322966 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2018-08-02 14:49 |
| I backported commit a86339b83fbd0932e0529a3c91935e997a234582 from master: commit 3243f8c1fb16b6de73f1d7a30f5d09047553bce3, but I don't have access to arm64, so I cannot test if the backport fixes test_ctypes on arm64. |
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