[issue35235] Access violation on alloc in Windows x86-64 python, pymalloc_alloc

Victor Milovanov added the comment: A bit more information: pool->freeblock for the broken pool looks like this: 0xXYZ? while pool itself looks like this: 0x??XYZ000 -- ___ Python tracker

[issue35235] Access violation on alloc in Windows x86-64 python, pymalloc_alloc

Victor Milovanov added the comment: In my case it always happens in pymalloc_alloc when size == 5, e.g. when accessing usedpools[10]. Specifically freeblock pointer in usedpools[10] is wy off (essentially, seemingly random number looking like 0xX000) where it is supposed to be (e.g.

[issue35235] Access violation on alloc in Windows x86-64 python, pymalloc_alloc

Victor Milovanov added the comment: This reproduces stably for me when running unit tests in Python.NET project at commit 5e276d9. -- nosy: +Victor Milovanov ___ Python tracker

[issue35235] Access violation on alloc in Windows x86-64 python, pymalloc_alloc

Mark Inderhees added the comment: Correction to my previous post. I did use capital X, ie '-X dev'. -- ___ Python tracker ___ ___

[issue35235] Access violation on alloc in Windows x86-64 python, pymalloc_alloc

Mark Inderhees added the comment: I have reproduced this with both PYTHONMALLOC=debug and "py -3.7 -x dev ", but it did not print out any allocation debug info. When using this option, it does take many more attempts to hit the issue than if running without debugging turned on. Is there

[issue35235] Access violation on alloc in Windows x86-64 python, pymalloc_alloc

STINNER Victor added the comment: Try to reproduce your bug using PYTHONMALLOC=debug environment variable: https://pythondev.readthedocs.io/debug_tools.html#memory-debugger On Python 3.7, you can use "py -3.7 -X dev program.py" (-X dev option) to enable PYTHONMALLOC=debug. -- nosy:

[issue35235] Access violation on alloc in Windows x86-64 python, pymalloc_alloc

Mark Inderhees added the comment: Actually, I have now seen this in full installed python. I have updated the title. -- title: Access violation on alloc in Windows x86-64 embeddable python, pymalloc_alloc -> Access violation on alloc in Windows x86-64 python, pymalloc_alloc