Forced termination of aiotools.fork is not working on macOS

[jopemachine]

What Operating System(s) are you seeing this problem on?

macOS 15.0.1

Backend.AI version

main

Describe the bug

After sending a SIGINT signal, if the process does not terminate within a specified period, aiotool.afork() sends a SIGKILL signal to forcibly terminate the process.

This mechanism works without issues on Linux, where it operates via PidfdChildProcess, but it is not functioning on macOS.

Debugging results suggest that the issue may be related to the timing of setting self._terminated to True.

This may be an upstream issue with aiotools, but as it is also affecting the behavior of Backend.AI, I am creating an issue for it.

To Reproduce

1. Start the Backend.AI manager server.
2. Shut down the Redis container.
3. Press Ctrl + C to send the SIGINT signal.
4. Although below log appear, the SIGKILL signal is not actually sent. So, the manager process also does not terminate.

2024-11-06 14:26:38.036 WARNING aiotools.server [10753] Timeout during waiting for child processes; killing all

Note

This example uses the manager component, but the issue can be reproduced with other components as well.

Expected Behavior

The SIGKILL signal is sent successfully, and the manager process terminates.
(Behavior on Linux.)

Anything else?

None