Re: Converting kselftest test modules to kunit

Muhammad Usama Anjum
2024-07-16T08:11:22Z

On 7/15/24 9:40 PM, Kees Cook wrote:
> 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.
I started investigated when I found that kselftest doesn't parse the kernel
logs to mark these tests pass/fail. (kselftest/lib is good example of it)

>
>> 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.
lib
test_bitmap
prime_numbers
test_printf
test_scanf
test_strscpy (already converted, need to remove this test)
lock
test-ww_mutex module
net
test_blackhole_dev
user
test_user_copy (probably already converted, need to remove this test)
firmware
test_firmware
fpu
test_fpu

Most of these modules are found in lib/*.

Would it be desired to move these to kunit?

--
BR,
Muhammad Usama Anjum