gh-151510: Fix __lazy_import__ without frame

[aisk]

I did not add a test because the fix is a straightforward, and exercising this would require extra _testcapi scaffolding to call __lazy_import__ without a Python frame.

Test added.

• Issue: bltinmodule.c: lazy_import NULL deref without Python frame #151510

[sobolevn]

Can we test this?

[sobolevn]

LGTM! Thanks!

[pablogsal]

Thanks for the fix @aisk !

[miss-islington-app]

Thanks @aisk for the PR, and @pablogsal for merging it 🌮🎉.. I'm working now to backport this PR to: 3.15.
🐍🍒⛏🤖

[bedevere-app]

GH-151610 is a backport of this pull request to the 3.15 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Debian root 3.x (tier-1) has failed when building commit eff805b.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/345/builds/14521) and take a look at the build logs.
4. Check if the failure is related to this commit (eff805b) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/345/builds/14521

Failed tests:

• test.test_multiprocessing_fork.test_misc

Failed subtests:

• test_large_pool - test.test_multiprocessing_fork.test_misc.MiscTestCase.test_large_pool

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/_test_multiprocessing.py", line 7311, in test_large_pool
rc, out, err = script_helper.assert_python_ok(testfn)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/support/script_helper.py", line 182, in assert_python_okreturn _assert_python(True, *args, **env_vars)
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/support/script_helper.py", line 167, in _assert_python
res.fail(cmd_line)
~~~~~~~~^^^^^^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/support/script_helper.py", line 80, in failraiseAssertionError(f"Process return code is {exitcode}\n"...<10 lines>...f"---")
AssertionError: Process return code is 1
command line: ['/root/buildarea/3.x.angelico-debian-amd64/build/python', '-X', 'faulthandler', '-I', '@test_1237050_tmpæ']
Traceback (most recent call last):
File "<string>", line 1, in <module>import sys; from multiprocessing.forkserver import main; main(10, 11, ['__main__'], sys_argv=sys.argv[1:], **{'sys_path': ['/root/buildarea/3.x.angelico-debian-amd64/build/target/lib/python316.zip', '/root/buildarea/3.x.angelico-debian-amd64/build/Lib', '/root/buildarea/3.x.angelico-debian-amd64/build/build/lib.linux-x86_64-3.16'], 'main_path': '/root/buildarea/3.x.angelico-debian-amd64/build/build/test_python_1237050æ/@test_1237050_tmpæ', 'authkey_r': 13})
~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/forkserver.py", line 406, in main
pid = os.fork()
OSError: [Errno 12] Cannot allocate memory
Traceback (most recent call last):
File "/root/buildarea/3.x.angelico-debian-amd64/build/build/test_python_1237050æ/@test_1237050_tmpæ", line 4, in <module>with multiprocessing.Pool(200) as p:
~~~~~~~~~~~~~~~~~~~~^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/context.py", line 119, in Poolreturn Pool(processes, initializer, initargs, maxtasksperchild,
context=self.get_context())
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/pool.py", line 215, in __init__self._repopulate_pool()
~~~~~~~~~~~~~~~~~~~~~^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/pool.py", line 306, in _repopulate_poolreturnself._repopulate_pool_static(self._ctx, self.Process,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^self._processes,
^^^^^^^^^^^^^^^^...<3 lines>...self._maxtasksperchild,
^^^^^^^^^^^^^^^^^^^^^^^self._wrap_exception)
^^^^^^^^^^^^^^^^^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/pool.py", line 329, in _repopulate_pool_static
w.start()
~~~~~~~^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/process.py", line 121, in startself._popen =self._Popen(self)
~~~~~~~~~~~^^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/context.py", line 309, in _Popenreturn Popen(process_obj)
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/popen_forkserver.py", line 35, in __init__super().__init__(process_obj)
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/popen_fork.py", line 20, in __init__self._launch(process_obj)
~~~~~~~~~~~~^^^^^^^^^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/popen_forkserver.py", line 59, in _launchself.pid = forkserver.read_signed(self.sentinel)
~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/multiprocessing/forkserver.py", line 472, in read_signedraiseEOFError('unexpected EOF')
EOFError: unexpected EOF
---

[aisk]

The buildbot failure should be unrelated.