Re: Converting kselftest test modules to kunit

Kees Cook
2024-07-15T16:40:01Z

On Mon, Jul 15, 2024 at 03:09:24PM +0500, Muhammad Usama Anjum wrote:
> Hi Kees and All,
>
> There are several tests in kselftest subsystem which load modules to tests
> the internals of the kernel. Most of these test modules are just loaded by
> the kselftest, their status isn't read and reported to the user logs. Hence
> they don't provide benefit of executing those tests.
>
> I've found patches from Kees where he has been converting such kselftests
> to kunit tests [1]. The probable motivation is to move tests output of
> kselftest subsystem which only triggers tests without correctly reporting
> the results. On the other hand, kunit is there to test the kernel's
> internal functions which can't be done by userspace.
>
> Kselftest: Test user facing APIs from userspace
> Kunit: Test kernel's internal functions from kernelspace

I would say this is a reasonable guide to how these things should
be separated, yes. That said, much of what was kind of ad-hoc kernel
internals testing that was triggered via kselftests is better done via
KUnit these days, but not everything.

> This brings me to conclusion that kselftest which are loading modules to
> test kernelspace should be converted to kunit tests. I've noted several
> such kselftests.

I would tend to agree, yes. Which stand out to you? I've mainly been
doing the conversions when I find myself wanting to add new tests, etc.

--
Kees Cook