Linus Lays down the Law
The Linux kernel team spent 6 months debating LLM usage in kernel development. They've now published an official policy.
What happened
A developer named Sasha Levin submitted a 19-line kernel patch (replacing an old hash table with a new define_hashtable function). It was reviewed and merged into Linux 6.15. However, it had a subtle bug – the __read_mostly annotation was removed, causing a performance regression.
The real controversy erupted when Sasha gave a talk at the Open Source Summit revealing the patch was LLM-generated – without having disclosed that during the review process. Reviewers were upset: “If I had known it was AI-generated, I would have reviewed it more carefully.”
Prime's take
- On “I would have reviewed harder” :: Prime is skeptical of this argument. A code review is a code review – you should put on your thinking cap regardless of who wrote it. Even he, as a self-described layman, could see the
__read_mostlydifference in 19 lines. He sees this as “cope” from reviewers who missed the bug. - On the new policy :: The kernel team published an “AI Coding Assistance” document requiring:
- All AI-assisted code must be license-compatible
- AI agents cannot add
Signed-off-bytags – onlyAssisted-bytags - A human must own the code, fully understand it, and vouch for it
Prime thinks this is “a pretty good approach” but predicts it's a stopgap – within 1-2 years, the volume of AI-generated patches could 10x and overwhelm human reviewers.
- On the junior developer problem :: Quotes a comment: if juniors outsource their understanding to LLMs, there will be fewer future reviewers. Prime sympathizes – learning is his “culture.”
- On coding being the fun part :: Strongly agrees with the comment that “writing code is already the easiest and most enjoyable part of software development.” The hard part is figuring out what to build. Yet that fun part is what AI is automating.
- On copyright :: Believes there's serious legal gray area – can you have “clean room engineering” if the AI has copyrighted code in its weights? Notes Microsoft offers legal indemnity for Copilot users. Ends with a pointed remark that AI companies face no consequences for mass scraping while Aaron Swartz was prosecuted for far less.
Bottom line: Prime remains cautiously optimistic – expertise will be needed “for quite some time,” and this is still “one of the greatest days to be writing software.”