Slower atexit methods do not run to completion

[parantapa]

Description

Cleanup methods that are slower do not run to completion when restarting kernel.

Reproduce

1. Create a new IPython notebook in Jupyter Lab.
2. Create and execute a new cell with the following code

import atexit
import time
from pathlib import Path

def write_hello():
    time.sleep(5)
    Path("hello.txt").write_text("hello")

atexit.register(write_hello)

3. Click on "Restart kernel"
4. The new file "hello.txt" was not created.

Expected behavior

The "hello.txt" should have been created.

Context

• Operating System and version: ArchLinux
• Browser and version: Firefox Developer version 125.0b6
• JupyterLab version: 4.1.6
• Jupyter server version: 2.14.0

Additional info

Jupyter lab shows a TimeoutError on console.

[E 2024-05-02 10:50:31.388 ServerApp] Uncaught exception GET /api/kernels/28d27336-01eb-4fed-9b24-e5b4a1ae8ef4/channels?session_id=3fa3bd68-c341-4029-b71b-92c68bdc3ba6 (127.0.0.1)
    HTTPServerRequest(protocol='http', host='localhost:8888', method='GET', uri='/api/kernels/28d27336-01eb-4fed-9b24-e5b4a1ae8ef4/channels?session_id=3fa3bd68-c341-4029-b71b-92c68bdc3ba6', version='HTTP/1.1', remote_ip='127.0.0.1')
    Traceback (most recent call last):
      File "/home/parantapa/miniconda3/envs/notebook_env/lib/python3.11/site-packages/tornado/web.py", line 1790, in _execute
        result = await result
                 ^^^^^^^^^^^^
      File "/home/parantapa/miniconda3/envs/notebook_env/lib/python3.11/site-packages/jupyter_server/services/kernels/websocket.py", line 65, in get
        await self.pre_get()
      File "/home/parantapa/miniconda3/envs/notebook_env/lib/python3.11/site-packages/jupyter_server/services/kernels/websocket.py", line 59, in pre_get
        await self.connection.prepare()
      File "/home/parantapa/miniconda3/envs/notebook_env/lib/python3.11/site-packages/jupyter_server/services/kernels/connection/channels.py", line 318, in prepare
        raise TimeoutError(msg)
    TimeoutError: Kernel never reached an 'alive' state.

This error is gone when using a larger kernel_info_timeout. However, the atexit method still does not run to completion.

The above code works as expected if run from IPython (inside shell).

I have been trying to find the spot in Jupyter Lab, Jupyter Server and Ipython that is responsible for killing the kernel. But I since I am not familiar enough, I haven't figured it out.

I had posted this issue on JupyterLab https://github.com/jupyterlab/jupyterlab/issues/16276#issue-2275760074 and was told this might be a better place to report the issue.