`Windows fatal exception: access violation` in thick mode

[CaselIT]

1. What versions are you using?

platform.platform: Windows-10-10.0.19044-SP0
sys.maxsize > 2**32: True
platform.python_version: 3.10.4
oracledb.__version__: 1.0.0

I'm using oracle 21.3.0.0, with client version (21, 3, 0, 0, 0)

2. Is it an error or a hang or a crash?
   A crash of the python interpreter

3. What error(s) or behavior you are seeing?

Windows fatal exception: access violation

Current thread 0x00001558 (most recent call first):
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\oracledb\connection.py", line 302 in close
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\lib\sqlalchemy\engine\default.py", line 599 in do_close
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\lib\sqlalchemy\pool\base.py", line 316 in _close_connection
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\lib\sqlalchemy\pool\base.py", line 812 in __close
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\lib\sqlalchemy\pool\base.py", line 745 in invalidate
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\lib\sqlalchemy\pool\base.py", line 1343 in invalidate
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\lib\sqlalchemy\engine\base.py", line 633 in invalidate
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\test\engine\test_reconnect.py", line 1112 in test_rollback_on_invalid_twophase
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\lib\sqlalchemy\testing\exclusions.py", line 121 in _do
  File "C:\Users\my_user\Dev\GitHub\sqlalchemy\lib\sqlalchemy\testing\exclusions.py", line 93 in decorate
  File "<string>", line 2 in test_rollback_on_invalid_twophase
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\python.py", line 192 in pytest_pyfunc_call
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_callers.py", line 39 in _multicall
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_manager.py", line 80 in _hookexec
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_hooks.py", line 265 in __call__
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\python.py", line 1761 in runtest
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\runner.py", line 166 in pytest_runtest_call
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_callers.py", line 39 in _multicall
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_manager.py", line 80 in _hookexec
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_hooks.py", line 265 in __call__
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\runner.py", line 259 in <lambda>
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\runner.py", line 338 in from_call
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\runner.py", line 258 in call_runtest_hook
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\runner.py", line 219 in call_and_report
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\runner.py", line 130 in runtestprotocol
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\runner.py", line 111 in pytest_runtest_protocol
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_callers.py", line 39 in _multicall
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_manager.py", line 80 in _hookexec
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_hooks.py", line 265 in __call__
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\main.py", line 347 in pytest_runtestloop
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_callers.py", line 39 in _multicall
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_manager.py", line 80 in _hookexec
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_hooks.py", line 265 in __call__
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\main.py", line 322 in _main
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\main.py", line 268 in wrap_session
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\main.py", line 315 in pytest_cmdline_main
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_callers.py", line 39 in _multicall
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_manager.py", line 80 in _hookexec
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\pluggy\_hooks.py", line 265 in __call__
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\config\__init__.py", line 164 in main
  File "C:\Users\my_user\miniconda3\envs\sa\lib\site-packages\_pytest\config\__init__.py", line 187 in console_main
  File "C:\Users\my_user\miniconda3\envs\sa\Scripts\pytest.exe\__main__.py", line 7 in <module>
  File "C:\Users\my_user\miniconda3\envs\sa\lib\runpy.py", line 86 in _run_code
  File "C:\Users\my_user\miniconda3\envs\sa\lib\runpy.py", line 196 in _run_module_as_main
Windows fatal exception: code 0xebadebad

4. Does your application call init_oracle_client()?

yes

5. Include a runnable Python script that shows the problem.

Sadly I cannot reproduce it. I've tried multiple times re-running the same command but it does not reproduce.
The crash happened while implementing support for the oracledb driver in sqlalchemy, running pytest --dburi oracle+oracledb://scott:tiger@127.0.0.1:1521/?service_name=XEPDB1 .\test\engine\ and momentarily enabling the thick mode.

The interpreter crashed while executing this test:
test/engine/test_reconnect.py::RealReconnectTest_oracle+oracledb_21_3_0_0_0::test_rollback_on_invalid_twophase
https://github.com/sqlalchemy/sqlalchemy/blob/ad86d32f7fbd1c6deda8ff3bebe0595c0f2986cc/test/engine/test_reconnect.py#L1108-L1112

I know it's not much to work on, but it's all I have.
I've reported since from the stack trace it seems to be a double free or similar since it happened in the close method, so maybe something useful can be gathered from it event with this few information.

Let me know if I can be of further help

[cjbj]

Thanks for logging it; we will do some code reviews etc and see if we can identify what's going on.

[CaselIT]

Ok, a colleague of mine had an unrelated crash of python and mentioned that windows logs an event if an application crashes. I've checked on the machine where I encountered this crash and sure enough there's a log in there, reported below.

seems that KERNELBASE.dll module crashed. Not sure if it can be of any help.

Faulting application name: python.exe, version: 3.10.4150.1013, time stamp: 0x62445d6c
Faulting module name: KERNELBASE.dll, version: 10.0.19041.1706, time stamp: 0x458acb5b
Exception code: 0xc0000005
Fault offset: 0x0000000000034fd9
Faulting process id: 0x61ec
Faulting application start time: 0x01d877760a6b901c
Faulting application path: C:\Users\my_user\miniconda3\envs\sa\python.exe
Faulting module path: C:\Windows\System32\KERNELBASE.dll
Report Id: 21a4f758-4c54-45e1-b886-deeb98f11563
Faulting package full name: 
Faulting package-relative application ID: 

just fyi I've never reproduced it again (but I've not used oracledb much after adding support for it in sqlalchemy)

[anthony-tuininga]

I believe this issue was resolved in the 1.4.2 release. We had another report that was not intermittent and were able to get to the bottom of it, thankfully!

[CaselIT]

Thanks for following up. Glad you had a reproducible report