Kernel Guidelines for Tool-Generated Content

Purpose

Kernel contributors have been using tooling to generate contributions for a long time. These tools can increase the volume of contributions. At the same time, reviewer and maintainer bandwidth is a scarce resource. Understanding which portions of a contribution come from humans versus tools is helpful to maintain those resources and keep kernel development healthy.

The goal here is to clarify community expectations around tools. This lets everyone become more productive while also maintaining high degrees of trust between submitters and reviewers.

Out of Scope

These guidelines do not apply to tools that make trivial tweaks to preexisting content. Nor do they pertain to tooling that helps with menial tasks. Some examples:

  • Spelling and grammar fix ups, like rephrasing to imperative voice

  • Typing aids like identifier completion, common boilerplate or trivial pattern completion

  • Purely mechanical transformations like variable renaming

  • Reformatting, like running Lindent, clang-format or rust-fmt

Even whenever your tool use is out of scope, you should still always consider if it would help reviewing your contribution if the reviewer knows about the tool that you used.

In Scope

These guidelines apply when a meaningful amount of content in a kernel contribution was not written by a person in the Signed-off-by chain, but was instead created by a tool.

Detection of a problem and testing the fix for it is also part of the development process; if a tool was used to find a problem addressed by a change, that should be noted in the changelog. This not only gives credit where it is due, it also helps fellow developers find out about these tools.

Some examples:

  • Any tool-suggested fix such as checkpatch.pl --fix

  • Coccinelle scripts

  • A chatbot generated a new function in your patch to sort list entries.

  • A .c file in the patch was originally generated by a coding assistant but cleaned up by hand.

  • The changelog was generated by handing the patch to a generative AI tool and asking it to write the changelog.

  • The changelog was translated from another language.

If in doubt, choose transparency and assume these guidelines apply to your contribution.

Guidelines

First, read the Developer’s Certificate of Origin: Submitting patches: the essential guide to getting your code into the kernel. Its rules are simple and have been in place for a long time. They have covered many tool-generated contributions. Ensure that you understand your entire submission and are prepared to respond to review comments.

Second, when making a contribution, be transparent about the origin of content in cover letters and changelogs. You can be more transparent by adding information like this:

  • What tools were used?

  • The input to the tools you used, like the Coccinelle source script.

  • If code was largely generated from a single or short set of prompts, include those prompts. For longer sessions, include a summary of the prompts and the nature of resulting assistance.

  • Which portions of the content were affected by that tool?

  • How is the submission tested and what tools were used to test the fix?

As with all contributions, individual maintainers have discretion to choose how they handle the contribution. For example, they might:

  • Treat it just like any other contribution.

  • Reject it outright.

  • Treat the contribution specially, for example, asking for extra testing, reviewing with extra scrutiny, or reviewing at a lower priority than human-generated content.

  • Ask for some other special steps, like asking the contributor to elaborate on how the tool or model was trained.

  • Ask the submitter to explain in more detail about the contribution so that the maintainer can be assured that the submitter fully understands how the code works.

  • Suggest a better prompt instead of suggesting specific code changes.

If tools permit you to generate a contribution automatically, expect additional scrutiny in proportion to how much of it was generated.

As with the output of any tooling, the result may be incorrect or inappropriate. You are expected to understand and to be able to defend everything you submit. If you are unable to do so, then do not submit the resulting changes.

If you do so anyway, maintainers are entitled to reject your series without detailed review.