kaxil opened a new pull request, #64874: URL: https://github.com/apache/airflow/pull/64874
On macOS, the task supervisor's bare os.fork() copies the parent's Objective-C runtime state into the child process. When the child later triggers ObjC class initialization (e.g. socket.getaddrinfo -> system DNS resolver -> Security.framework -> +[NSNumber initialize]), the runtime detects the corrupted state and crashes with SIGABRT/SIGSEGV. This is a well-documented macOS platform limitation -- Apple's ObjC runtime, CoreFoundation, and libdispatch are not fork-safe. CPython changed multiprocessing's default start method to "spawn" on macOS in 3.8 for this reason, but Airflow's TaskSDK supervisor uses os.fork() directly. The fix: on macOS, immediately call os.execv() after os.fork() for task execution subprocesses. The exec replaces the child's address space, giving it clean ObjC state. The socketpair FDs survive across exec (marked inheritable) and the child reads their numbers from an environment variable. Only task execution (target=_subprocess_main) uses fork+exec. DAG processor and triggerer pass different targets and keep bare fork -- they don't make network calls that trigger the macOS crash. References: - https://github.com/python/cpython/issues/105912 - https://github.com/python/cpython/issues/58037 - https://github.com/apache/airflow/discussions/24463 <!-- SPDX-License-Identifier: Apache-2.0 https://www.apache.org/licenses/LICENSE-2.0 --> <!-- Thank you for contributing! Please provide above a brief description of the changes made in this pull request. Write a good git commit message following this guide: http://chris.beams.io/posts/git-commit/ Please make sure that your code changes are covered with tests. And in case of new features or big changes remember to adjust the documentation. Feel free to ping (in general) for the review if you do not see reaction for a few days (72 Hours is the minimum reaction time you can expect from volunteers) - we sometimes miss notifications. In case of an existing issue, reference it using one of the following: * closes: #ISSUE * related: #ISSUE --> --- ##### Was generative AI tooling used to co-author this PR? <!-- If generative AI tooling has been used in the process of authoring this PR, please change below checkbox to `[X]` followed by the name of the tool, uncomment the "Generated-by". --> - [ ] Yes (please specify the tool below) <!-- Generated-by: [Tool Name] following [the guidelines](https://github.com/apache/airflow/blob/main/contributing-docs/05_pull_requests.rst#gen-ai-assisted-contributions) --> --- * Read the **[Pull Request Guidelines](https://github.com/apache/airflow/blob/main/contributing-docs/05_pull_requests.rst#pull-request-guidelines)** for more information. Note: commit author/co-author name and email in commits become permanently public when merged. * For fundamental code changes, an Airflow Improvement Proposal ([AIP](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+Improvement+Proposals)) is needed. * When adding dependency, check compliance with the [ASF 3rd Party License Policy](https://www.apache.org/legal/resolved.html#category-x). * For significant user-facing changes create newsfragment: `{pr_number}.significant.rst`, in [airflow-core/newsfragments](https://github.com/apache/airflow/tree/main/airflow-core/newsfragments). You can add this file in a follow-up commit after the PR is created so you know the PR number. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
