Crash report

What happened?

The second breakpoint segfaults on Windows (==access violation).

import asyncio async def main(): def inner(): breakpoint() pass asyncio.create_task(asyncio.to_thread(inner)) asyncio.create_task(asyncio.to_thread(inner)) asyncio.ensure_future(main()) asyncio.get_event_loop().run_forever()

Core of the problem is in the myreadline.c module.
Implementing a fix...

CPython versions tested on:

3.12, CPython main branch

Operating systems tested on:

Windows

Output from running 'python -VV' on the command line:

No response

Linked PRs

• gh-123321: Fix Parser/myreadline.c to prevent a segfault during a multi-threaded race #123323
• [3.13] gh-123321: Fix Parser/myreadline.c to prevent a segfault during a multi-threaded race (GH-123323) #123676
• [3.12] gh-123321: Fix Parser/myreadline.c to prevent a segfault during a multi-threaded race (GH-123323) #123677
• gh-123321: Make Parser/myreadline.c locking safe in free-threaded build #123690
• [3.13] gh-123321: Make Parser/myreadline.c locking safe in free-threaded build (GH-123690) #123798