[New-bugs-announce] [issue42335] Python Crashes Exception code 0xc0000374 ntdll.dll

[Charles Staton]

New submission from Charles Staton <cstaton at ftlg.net>:

Hello, I am experiencing crashes of Python 3.8.5 (32 bit) on multiple identical Windows 10 x64 (Enterprise 2016 LTSB) machines. The Crashes are of the sort with the Windows popup "Python has stopped working" and there is no traceback.

The crashes occur sporadically. My program might run several days or just an hour, but invariably Python will crash if you wait long enough. I have attached a zip file containing all of the information provided by Windows in Application Logs, as well as some AppVerifier logs. I do not believe the AppVerifier logs are relevant however, as running my program with AppVerifier turned on causes Python to crash immediately upon startup and the information provided by Windows in Application Logs seems to indicate that it's AppVerifier crashing, not Python.

My program is quite large and is importing several libraries. It has a PyQt5 GUI, and I'm using PyQt5's QThreadpool() to run several threads concurrently which do various things like: communicate with a web API (rauth, requests), communicate with a PLC (pyModbusTCP), communicate with another PLC (python-Snap7), communicate with an RS485 printer (pySerial), write CSV logs to a network drive, et. al. 

I'm running this program in a venv setup by PyCharm. The full information is in the attached zip file but here's an excerpt:

Faulting application name: python.exe, version: 3.8.5150.1013, time stamp: 0x5f15bc04
Faulting module name: ntdll.dll, version: 10.0.14393.206, time stamp: 0x57dacde1
Exception code: 0xc0000374
Fault offset: 0x000d9841
Faulting process id: 0x1550
Faulting application start time: 0x01d6b839c684e37d
Faulting application path: C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\python.exe
Faulting module path: C:\Windows\SYSTEM32\ntdll.dll
Report Id: 24636ab4-7c06-4cd6-b8f8-4e20bfc59dce

Googling various clues has given me a vague clue that this is caused by Python attempting to access memory that it shouldn't. I have no idea how that happens or why. I'm clueless as to how I should go about troubleshooting this. If anyone can help I will be very grateful.

----------
components: Interpreter Core, Library (Lib), ctypes
files: Python Crash Data.zip
messages: 380847
nosy: strantor
priority: normal
severity: normal
status: open
title: Python Crashes Exception code 0xc0000374 ntdll.dll
versions: Python 3.8
Added file: https://bugs.python.org/file49594/Python Crash Data.zip

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue42335>
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