Re: Introduce Sashiko (agentic review of Linux kernel changes)

Re: Introduce Sashiko (agentic review of Linux kernel changes)

[SeongJae Park]

Hello Roman,

On Tue, 17 Mar 2026 15:31:11 +0000 Roman Gushchin <roman.gushchin@linux.dev> wrote:

> Hello,
> 
> I'm happy to share something my colleagues and I have been working on
> for the last several months:
> Sashiko - an agentic system for Linux kernel changes.
> 
> First, Sashiko is available as a service at:
>   * https://sashiko.dev

Great work.  Thank you!

There are many similar tools but this is the first free web service I know.
I'm still feeling uncomfortable or not prepared for running some AI tools on my
own.  Therefore I was only waiting for some nice people sharing their AI review
results (some people including Chris Mason did, and it was really helpful,
thanks again), or the arrival of this kind of public and just working service.
This feels like the chat-gpt moment to me.

> 
> It reviews all patches sent to LKML and several other Linux kernel
> mailing lists using the Gemini 3.1 Pro model.
> 
> I want to thank my employer, Google, for providing the ML compute
> resources and infrastructure for making this project real.
> 
> Sashiko is written in Rust from scratch, mostly using Gemini CLI. It's
> fully self-contained and does not rely on any CLI coding tools. It
> supports various LLMs (at this moment mostly tested with Gemini
> Pro/Flash and slightly with Claude).
> 
> And finally it's fully open-source:
>   * https://github.com/sashiko-dev/sashiko

Awesome.  I'm still feeling uncomfortable or not prepared to running some AI
tools on my own.  But I will try to find ways to contribute.

> 
> It's licensed under the Apache-2.0 License, and the ownership of the
> project was transferred to the Linux Foundation. Contributions are
> really welcome using DCO.
> 
> Sashiko is based on a set of open-source prompts initially developed by
> Chris Mason:
>   * https://github.com/masoncl/review-prompts/

Kudos to Chris!

> 
> But Sashiko leverages a different multi-stage review protocol, which
> somewhat mimics the human review process and forces the LLM to look at
> the proposed change from different angles.
> 
> In my measurement, Sashiko was able to find 53% of bugs based
> on a completely unfiltered set of 1,000 recent upstream issues using
> "Fixes:" tags (using Gemini 3.1 Pro). Some might say that 53% is not
> that impressive, but 100% of these issues were missed by human reviewers.
> Also, many of these issues (like tricky build failures, performance
> problems, etc) are very hard/impossible to spot from reviewing the code,
> so arguably 100% is not reachable. We started with low 30's a couple of
> months ago; better models and improvements in the review protocol and
> subsystem prompts pushed it to low 50's. With better LLMs and collective
> effort on prompts we can push even further.
> 
> Measuring false positives is much harder, but based on manual reviews of
> reviews, it's pretty good: it's rarely dead wrong, but sometimes it can
> nitpick or find too many low-value issues. In many cases, it can be
> improved with prompt engineering.
> 
> * What's next?
> 
> This is our first version and it's obviously not perfect. There is a
> long list of fixes and improvements to make. Please, don't expect it to
> be 100% reliable, even though we'll try hard to keep it up and running.
> Please use github issues or email me any bug reports and feature
> requests, or send PR's.
> 
> As of now, Sashiko only provides a web interface;
> however, Konstantin Ryabitsev is already adding sashiko.dev support to b4,
> and SeongJae Park is adding support to hkml.
> That was really fast, thank you!

hkml support was available owing to Sashiko providing the decent API, and b4's
use of it is open source.  Kudos to Sashiko team and Konstantin.  I'm planning
to make more integration into hkml, for my workflow and based on other hkml
user feedback.

> 
> We're working on adding an email interface to Sashiko, and soon Sashiko
> will be able to send out reviews over email - similar to what the bpf
> subsystem already has. It will be opt-in by subsystem and will have options
> to CC only the author of the patch, maintainers, volunteers, or send a
> fully public reply. If you're a maintainer and have a strong preference
> to get reviews over email, please let me know.

I, as the maintainer of DAMON subsystem (damon@lists.linux.dev), do have a
strong preference to get reviews over email for all patches that sent to the
mailing list.  I'm already manually doing that.  I'm planning to extend hkml
for doing this easier.  It would be nice and efficient if Sashiko can do this
on its own.

> 
> We also desperately need better benchmarks, especially when it comes to
> false positives. Having a decent vetted set of officially perfect
> commits can help with this.

I'm also curious if there is a public channel for giving feedback about the
reviews.  As you mentioned above, Sashiko sometimes says something that is not
technically correct.  I'm wondering if there is a way to let Sashiko knows such
things for improvement.

> 
> Finally, some subsystems have a good prompts coverage and some don't. It
> doesn't have to be lengthy documentation (and it might actually be
> counter-productive), but having a small list of things to look at - some
> high-level concepts which are hard to grasp from the code, etc. - can
> help a lot with both bug discovery and false positives.

I found there is no prompt for DAMON.  I'm still convinced with Sashiko's
current review, and have no idea for DAMON-custom prompts.  So that's fine for
now.  I will consider adding something if I get some idea, though.

Again, thanks for making this.  Please keep making this improved and available.
I will also try to find ways to help.


Thanks,
SJ

[...]

Re: Introduce Sashiko (agentic review of Linux kernel changes)

[Roman Gushchin]

SeongJae Park <sj@kernel.org> writes:

> Hello Roman,
>
> On Tue, 17 Mar 2026 15:31:11 +0000 Roman Gushchin <roman.gushchin@linux.dev> wrote:
>
>> Hello,
>> 
>> I'm happy to share something my colleagues and I have been working on
>> for the last several months:
>> Sashiko - an agentic system for Linux kernel changes.
>> 
>> First, Sashiko is available as a service at:
>>   * https://sashiko.dev
>
> Great work.  Thank you!
>
> There are many similar tools but this is the first free web service I know.
> I'm still feeling uncomfortable or not prepared for running some AI tools on my
> own.  Therefore I was only waiting for some nice people sharing their AI review
> results (some people including Chris Mason did, and it was really helpful,
> thanks again), or the arrival of this kind of public and just working service.
> This feels like the chat-gpt moment to me.

Thank you!

>> 
>> It reviews all patches sent to LKML and several other Linux kernel
>> mailing lists using the Gemini 3.1 Pro model.
>> 
>> I want to thank my employer, Google, for providing the ML compute
>> resources and infrastructure for making this project real.
>> 
>> Sashiko is written in Rust from scratch, mostly using Gemini CLI. It's
>> fully self-contained and does not rely on any CLI coding tools. It
>> supports various LLMs (at this moment mostly tested with Gemini
>> Pro/Flash and slightly with Claude).
>> 
>> And finally it's fully open-source:
>>   * https://github.com/sashiko-dev/sashiko
>
> Awesome.  I'm still feeling uncomfortable or not prepared to running some AI
> tools on my own.  But I will try to find ways to contribute.
>
>> 
>> It's licensed under the Apache-2.0 License, and the ownership of the
>> project was transferred to the Linux Foundation. Contributions are
>> really welcome using DCO.
>> 
>> Sashiko is based on a set of open-source prompts initially developed by
>> Chris Mason:
>>   * https://github.com/masoncl/review-prompts/
>
> Kudos to Chris!
>
>> 
>> But Sashiko leverages a different multi-stage review protocol, which
>> somewhat mimics the human review process and forces the LLM to look at
>> the proposed change from different angles.
>> 
>> In my measurement, Sashiko was able to find 53% of bugs based
>> on a completely unfiltered set of 1,000 recent upstream issues using
>> "Fixes:" tags (using Gemini 3.1 Pro). Some might say that 53% is not
>> that impressive, but 100% of these issues were missed by human reviewers.
>> Also, many of these issues (like tricky build failures, performance
>> problems, etc) are very hard/impossible to spot from reviewing the code,
>> so arguably 100% is not reachable. We started with low 30's a couple of
>> months ago; better models and improvements in the review protocol and
>> subsystem prompts pushed it to low 50's. With better LLMs and collective
>> effort on prompts we can push even further.
>> 
>> Measuring false positives is much harder, but based on manual reviews of
>> reviews, it's pretty good: it's rarely dead wrong, but sometimes it can
>> nitpick or find too many low-value issues. In many cases, it can be
>> improved with prompt engineering.
>> 
>> * What's next?
>> 
>> This is our first version and it's obviously not perfect. There is a
>> long list of fixes and improvements to make. Please, don't expect it to
>> be 100% reliable, even though we'll try hard to keep it up and running.
>> Please use github issues or email me any bug reports and feature
>> requests, or send PR's.
>> 
>> As of now, Sashiko only provides a web interface;
>> however, Konstantin Ryabitsev is already adding sashiko.dev support to b4,
>> and SeongJae Park is adding support to hkml.
>> That was really fast, thank you!
>
> hkml support was available owing to Sashiko providing the decent API, and b4's
> use of it is open source.  Kudos to Sashiko team and Konstantin.  I'm planning
> to make more integration into hkml, for my workflow and based on other hkml
> user feedback.

Thank you for doing this!

>> 
>> We're working on adding an email interface to Sashiko, and soon Sashiko
>> will be able to send out reviews over email - similar to what the bpf
>> subsystem already has. It will be opt-in by subsystem and will have options
>> to CC only the author of the patch, maintainers, volunteers, or send a
>> fully public reply. If you're a maintainer and have a strong preference
>> to get reviews over email, please let me know.
>
> I, as the maintainer of DAMON subsystem (damon@lists.linux.dev), do have a
> strong preference to get reviews over email for all patches that sent to the
> mailing list.  I'm already manually doing that.  I'm planning to extend hkml
> for doing this easier.  It would be nice and efficient if Sashiko can do this
> on its own.

Noted. I'll enable it as soon as we'll have it.

>
>> 
>> We also desperately need better benchmarks, especially when it comes to
>> false positives. Having a decent vetted set of officially perfect
>> commits can help with this.
>
> I'm also curious if there is a public channel for giving feedback about the
> reviews.  As you mentioned above, Sashiko sometimes says something that is not
> technically correct.  I'm wondering if there is a way to let Sashiko knows such
> things for improvement.

As of now, I suggest using Github issues. Later on, you could simple
reply to Sashiko's emails.

But also realistically I likely won't be able to look into every single
false positive, so I'd really appreciate some initial analysis: e.g. if
there is a common pattern or a number of similar reviews with the same
problem.

>> 
>> Finally, some subsystems have a good prompts coverage and some don't. It
>> doesn't have to be lengthy documentation (and it might actually be
>> counter-productive), but having a small list of things to look at - some
>> high-level concepts which are hard to grasp from the code, etc. - can
>> help a lot with both bug discovery and false positives.
>
> I found there is no prompt for DAMON.  I'm still convinced with Sashiko's
> current review, and have no idea for DAMON-custom prompts.  So that's fine for
> now.  I will consider adding something if I get some idea, though.

My suggestion is to read through a number of DAMON-specific reviews and
see if there are any common patterns of false positives or missed
errors. Once you have a feeling like "Damn, Sashiko doesn't really
understand X about the DAMON!" then you put it into the prompt.

Thanks!