_asyncio.Task.__new__(_asyncio.Task).get_context() segfaults

[BHUVANSH855]

Crash report

What happened?

Calling _asyncio.Task.get_context() on an uninitialized Task created via __new__() crashes the interpreter with a segmentation fault.

Minimal reproducer

import _asyncio

_asyncio.Task.__new__(_asyncio.Task).get_context()

A more realistic case is an asyncio.Task subclass that overrides __init__() without calling super().__init__().

import asyncio

class MyTask(asyncio.Task):
    def __init__(self, *args, **kwargs):
        pass

MyTask.__new__(MyTask).get_context()

Actual behavior

The interpreter crashes with a segmentation fault (exit code 139).

Expected behavior

The interpreter should not crash. Accessing get_context() on an uninitialized Task should either return a well-defined value or raise a Python exception.

Analysis

Task instances are allocated using PyType_GenericNew, so fields are initially zero-initialized. The task_context field is initialized only in _asyncio_Task___init__().

However, _asyncio_Task_get_context_impl() currently does:

return Py_NewRef(self->task_context);

without checking whether task_context has been initialized. Calling Py_NewRef(NULL) dereferences a null pointer and crashes the interpreter.

For comparison, the adjacent methods _asyncio_Task_get_coro_impl() and _asyncio_Task_get_name_impl() both guard their corresponding fields before returning them, so the same half-initialized object does not crash when calling get_coro() or get_name().

The pure Python implementation also exposes get_context() by returning self._context, so bypassing initialization would result in a normal Python exception rather than a hard interpreter crash.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

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

Python 3.16.0a0 (heads/fix-154835-odict-desync-dirty:8b048eb35eb, Jul 28 2026, 20:03:25) [GCC 13.3.0]

Linked PRs

• gh-154871: Fix asyncio.Task.get_context() crash #154898

[picnixz]

Messing with C extensions with __new__ and __init__ is usually not considered a legitimate issue but if @kumaraditya303 wants to fix this, we can accept the patch.

I do not remember whether we fixed similar issues in the past though with missing super() calls.

Please avoid creating such issues in the future though.

[johnslavik]

I think in the second example the OP meant to show this:

import asyncio

class MyTask(asyncio.Task):
    def __init__(self, *args, **kwargs):
        pass

MyTask().get_context()  # crashes

Asyncio lets you set your own task factories, we do subclass asyncio.Task in tests (test_create_task and test_set_task_factory), many people subclass asyncio.Task: https://github.com/search?q=%2F%5CS%2B%5C%28asyncio%5C.Task%5C%29%3A%2F&type=code.

If I were to throw my two cents, I think this is worth fixing. To me it does look like it could randomly occur.

[picnixz]

Oh so if it's like that yes.