py: Fix two segfaults due to accessing uninitialized memory. #18732
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Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## master #18732 +/- ##
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- Coverage 98.41% 98.41% -0.01%
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Files 171 171
Lines 22324 22329 +5
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+ Hits 21971 21975 +4
- Misses 353 354 +1 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Code size report: |
Accessing obj->subobj[0] without verifying that it contains a valid object (instead of a type, or a non-initialized object) is not a good idea. Signed-off-by: Matthias Urlichs <matthias@urlichs.de>
Test basics/subclass_native_exc_noinit.py segfaults without them. Signed-off-by: Matthias Urlichs <matthias@urlichs.de>
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Added testcases to exercise the problem; one of them manages to reproduce the crash. I have no idea why the stackless test fails (works on my system). |
The test required `super().__new__` to exist, which the minimal build doesn't have. Signed-off-by: Matthias Urlichs <matthias@urlichs.de>
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While it might be possible to further improve the diff coverage, IMHO that effort is spent more productively elsewhere. |
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Summary
Accessing obj->subobj[0] without verifying that it contains a valid object (instead of a type, or a non-initialized object) is not a good idea.
Testing
My MoaT package has extensive MicroPython testcases. Before applying this PR the MicroPython process reliably segfaulted. This no longer happens.
Closes #17117 .