Torvalds Publishes a Linux Kernel Branch Built With Claude Code

Linus Torvalds published a branch in his mainline Linux repository on Sunday, Oct. 11, and its commit message says the code, test programs and review were done with Claude Code under his direction, according to Phoronix.

Phoronix writer Michael Larabel spotted the branch, named noref-filemap-read-with-llm, while waiting for the Linux 7.3-rc7 release. Torvalds normally hosts only the master branch in that repository. Phoronix published its report at 8:16 p.m. Eastern on Oct. 11.

What the noref-filemap-read-with-llm commit says

The change adapts memory management code so reads from the page cache, the kernel's in-memory copy of file data, skip folio reference counts. Phoronix says the target is a bottleneck where many threads making small reads of one file contend on that counting.

The commit message credits the tool in plain terms. As Phoronix quotes it, the code, the test programs, the review behind the commit's list of changes and the first draft of the cover text "were done with an LLM coding assistant (Claude Code) under my direction." The message adds: "The measurements were run on my machine."

Phoronix reports the performance results only in a chart. The commit page returned an error when this article tried to fetch it, so this article does not give the size of the gain.

The assoc_array tag found four bugs dating to 2013

A second Phoronix report, published Oct. 12, covers a tag named assoc-array-fixes that appeared on the same Sunday. Torvalds used LLM tools to make sense of a patch for an obscure bug in the kernel's assoc_array library, reported by Nils Ollrogge. Torvalds wrote that the code "was too obscure for me to follow."

A user-space test harness confirmed Ollrogge's bug and found three others. All four date to the library's first commit in 2013, according to Phoronix. The branch also splits some large functions into smaller ones so the code reads more easily.

In the tag message Torvalds wrote that he "did what I preach," Phoronix reports. That is a tag message, not a standard commit.

Date	What happened	Reported by
Jul. 16	Torvalds on the kernel mailing list: "Linux is not one of those anti-AI projects"	Virtualization Review
Oct. 11	noref-filemap-read-with-llm branch appears, crediting Claude Code	Phoronix
Oct. 12	assoc-array-fixes tag lands, four bugs traced to 2013	Phoronix

What Torvalds wrote in July

David Ramel of Virtualization Review reported on Jul. 16 that Torvalds answered a mailing-list comment calling the kernel's position broadly anti-LLM with: "Yes. And no, that's not the position of the Linux kernel." He wrote that "AI is a tool, just like other tools we use," and that "it's clearly a useful one."

He also wrote that the kernel makes decisions "primarily based on technical merit. Not fear of new tools." The same article lists the objections from other developers: low-quality automated submissions, heavier review loads, unclear code provenance and whether such contributions can be certified under the Developer Certificate of Origin.

The July statements were about what the project would accept from contributors. The October commit is the person with the final say on what merges attaching his own name to an LLM-assisted change and saying how it was made.

What is still unknown about Linux 7.4

Neither branch is in master. Phoronix says the patches will presumably be queued for the Linux 7.4 merge window and that whether the page cache change is merged is unknown. The material reviewed here contains no comment from Torvalds beyond the commit and tag text.

Agent-written changes at volume are straining source control elsewhere: Anthropic replaced Git with Scion after merges hit 30,401 in a day, and AWS's AI-DLC workflow runs 33 stages across seven coding agents.

The next observable event is the 7.4 merge window, which opens after Linux 7.3 ships. Phoronix does not give a date for either.