On 7/16/24 10:59 AM, Kees Cook wrote:
On Tue, Jul 16, 2024 at 01:11:14PM +0500, Muhammad Usama Anjum wrote:
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
Yeah, these would be nice to convert.
test_strscpy (already converted, need to remove this test)
Yup, converted in bb8d9b742aa7 ("string: Merge strscpy KUnit tests into
string_kunit.c")
lock
test-ww_mutex module
net
test_blackhole_dev
I don't know these very well, but yeah worth looking into.
user
test_user_copy (probably already converted, need to remove this test)
This is done in -next via cf6219ee889f ("usercopy: Convert test_user_copy to KUnit
test")
firmware
test_firmware
This might not work to convert: there's a userspace half for testing
firmware loading (see the kselftest side...)
fpu
test_fpu
Seems reasonable.
Most of these modules are found in lib/*.
Would it be desired to move these to kunit?
Checking with the authors/maintainer is probably the first thing to do;
check the git history to see who has been working on them.
Also maybe:
mm
gup_test
This is a classic case of testing a kernel API via ioctl into the
kernel, so I think it meets your criteria for moving to KUnit.
Having said that, I must now go try out KUnit in a bit more depth
before I'm sure that this will work out. But it should.
thanks,
--
John Hubbard
NVIDIA
