Re: [PATCH v2 RFC 0/7] KFuzzTest: a new kernel fuzzing framework

[Ethan Graham <ethan.w.s.graham@gmail.com>]

On Thu, Sep 4, 2025 at 11:11 AM David Gow <davidgow@google.com> wrote:
> Thanks, Ethan. I've had a bit of a play around with the
> kfuzztest-bridge tool, and it seems to work pretty well here. I'm
> definitely looking forward to trying out
>
> The only real feature I'd find useful would be to have a
> human-readable way of describing the data (as well as the structure),
> which could be useful when passing around reproducers, and could make
> it possible to hand-craft or adapt cases to work cross-architecture,
> if that's a future goal. But I don't think that it's worth holding up
> an initial version for.

That's a great idea for a future iteration.

> On the subject of architecture support, I don't see anything
> particularly x86_64-specific in here (or at least, nothing that
> couldn't be relatively easily fixed). While I don't think you need to
> support lots of architectures immediately, it'd be nice to use
> architecture-independant things (like the shared
> include/asm-generic/vmlinux.lds.h) where possible. And even if you're

You're absolutely right. I made some modifications locally, and there
seems to be no reason not to add all of the required section
definitions into the /include/asm-generic/vmlinux.lds.h.

> focusing on x86_64, supporting UML -- which is still x86
> under-the-hood, but has its own linker scripts -- would be a nice
> bonus if it's easy. Other things, like supporting 32-bit or big-endian
> setups are nice-to-have, but definitely not worth spending too much
> time on immediately (though if we start using some of the
> formats/features here for KUnit, we'll want to support them).
>
> Finally, while I like the samples and documentation, I think it'd be
> nice to include a working example of using kfuzztest-bridge alongside
> the samples, even if it's something as simple as including a line
> like:
> ./kfuzztest-bridge "some_buffer { ptr[buf] len[buf, u64]}; buf {
> arr[u8, 128] };"  "test_underflow_on_buffer" /dev/urandom

Definitely. I'll be sure to add that into the docs.