Re: [PATCH v1 0/8] Run KUnit tests late and handle faults

Mickaël Salaün
2024-03-01T19:20:03Z

On Fri, Mar 01, 2024 at 03:15:08PM +0800, David Gow wrote:
> On Fri, 1 Mar 2024 at 01:04, Mickaël Salaün <mic@digikod.net> wrote:
> >
> > Hi,
> >
>
> Thanks very much. I think there's a lot going on in this series, and
> it'd probably be easier to address if it were broken up a bit more.
>
> To take things one at a time:
>
> > This patch series moves KUnit test execution at the very end of kernel
> > initialization, just before launching the init process. This opens the
> > way to test any kernel code in its normal state (i.e. fully
> > initialized).
>
> I like the general idea here, but there are a few things to keep in mind:
> - We can already do this with tests built as modules.
> - We have explicit support for testing __init code, so if we want to
> keep that (and I think we do), we'll need to make sure that there
> remains a way to run tests before __init.
> - Behaviour changes here will need to be documented and tested well
> across all tests and architectures, so it's not something I'd want to
> land quickly.
> - The requirement to have a root filesystem set up is another thing
> we'll want to handle carefully.
> - As-is, the patch seems to break arm64.

Fair, I'll remove this patch from the next series.

>
> >
> > This patch series also teaches KUnit to handle kthread faults as errors,
> > and it brings a few related fixes and improvements.
>
> These seem very good overall. I want to look at the last location
> stuff in a bit more detail, but otherwise this is okay.

Thanks!

>
> Personally, I'd like to see this split out into a separate series,
> partly because I don't want to delay it while we sort the other parts
> of this series out, and partly because I have some other changes to
> the thread context stuff I think we need to make.

I'll do that today.

>
> >
> > New tests check NULL pointer dereference and read-only memory, which
> > wasn't possible before.
>
> These look interesting, but I don't like that they are listed as x86-specific.

I was reluctant to make it more broadly available because I only tested
on x86...

>
> >
> > This is useful to test current kernel self-protection mechanisms or
> > future ones such as Heki: https://github.com/heki-linux
> >
> > Regards,
>
> Thanks again. I'll do a more detailed review of the individual patches
> next week, but I'm excited to see this overall.

Good, you'll review the v2 then.

>
> Cheers,
> -- David
>
>
> >
> > Mickaël Salaün (8):
> > kunit: Run tests when the kernel is fully setup
> > kunit: Handle thread creation error
> > kunit: Fix kthread reference
> > kunit: Fix timeout message
> > kunit: Handle test faults
> > kunit: Fix KUNIT_SUCCESS() calls in iov_iter tests
> > kunit: Print last test location on fault
> > kunit: Add tests for faults
> >
> > include/kunit/test.h | 24 +++++-
> > include/kunit/try-catch.h | 3 -
> > init/main.c | 4 +-
> > lib/bitfield_kunit.c | 8 +-
> > lib/checksum_kunit.c | 2 +-
> > lib/kunit/executor.c | 81 ++++++++++++++------
> > lib/kunit/kunit-example-test.c | 6 +-
> > lib/kunit/kunit-test.c | 115 +++++++++++++++++++++++++++-
> > lib/kunit/try-catch.c | 33 +++++---
> > lib/kunit_iov_iter.c | 70 ++++++++---------
> > tools/testing/kunit/kunit_kernel.py | 6 +-
> > 11 files changed, 261 insertions(+), 91 deletions(-)
> >
> >
> > base-commit: d206a76d7d2726f3b096037f2079ce0bd3ba329b
> > --
> > 2.44.0
> >