os.PIDFD_NONBLOCK is missing, yet according to documentation it should be present

[n6koma7a]

Bug report

Bug description:

# Add a code block here, if required
import os
os.PIDFD_NONBLOCK

https://docs.python.org/3/library/os.html#os.PIDFD_NONBLOCK

python3.13 Wed 04 Dec 2024 01:57:39 AM +03
Python 3.13.0 (main, Oct 8 2024, 00:00:00) [GCC 14.2.1 20240912 (Red Hat 14.2.1-3)] on linux
Type "help", "copyright", "credits" or "license" for more information.

import os
os.PIDFD_NONBLOCK
Traceback (most recent call last):
File "", line 1, in
os.PIDFD_NONBLOCK
AttributeError: module 'os' has no attribute 'PIDFD_NONBLOCK'. Did you mean: 'EFD_NONBLOCK'?

CPython versions tested on:

3.13

Operating systems tested on:

Linux

[JelleZijlstra]

The docs say the constant is available on Linux >= 5.10.

However, I can replicate this on a Linux system running kernel 5.15 using current main:

$ uname -a
Linux devshared41 5.15.0-1070-aws #76~20.04.1-Ubuntu SMP Mon Sep 2 12:20:36 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
$ ./python -c 'import os; print(hasattr(os, "PIDFD_NONBLOCK"))'
False

The code looks correct:

cpython/Modules/posixmodule.c

Line 17410 in 12397a5

#ifdef PIDFD_NONBLOCK

And manpages confirm the constant should exist: https://man7.org/linux/man-pages/man2/pidfd_open.2.html

Maybe we're missing an #include?

cc @kumaraditya303 who added this in #93313

[stephen-hansen]

just browsing through here, looks like relevant kernel thread: https://lore.kernel.org/all/ZkrZb91EgZoaOybZ@t420/T/

Seems like the missing #include is on <linux/pidfd.h>.

[kumaraditya303]

Fixed by #127593