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From:   Joe Fradley <joefradley@google.com>
Date:   Mon, 22 Aug 2022 13:47:05 -0700
Message-ID: <CAF-60z2dc=5A9+3a8+v7F-CunKKesUD+2Q6OTEpmrpUa1SvcDA@mail.gmail.com>
Subject: Re: [PATCH 2/2] kunit: no longer call module_info(test, "Y") for
 kunit modules
To:     David Gow <davidgow@google.com>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Brendan Higgins <brendan.higgins@linux.dev>,
        kernel-team@android.com,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>,
        KUnit Development <kunit-dev@googlegroups.com>
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On Fri, Aug 19, 2022 at 1:34 AM David Gow <davidgow@google.com> wrote:
>
> On Thu, Aug 18, 2022 at 12:49 AM Joe Fradley <joefradley@google.com> wrote:
> >
> > Because KUnit test execution is not a guarantee with the kunit.enable
> > parameter we want to be careful to only taint the kernel only if an
> > actual test runs. Calling module_info(test, "Y") for every KUnit module
> > automatically causes the kernel to be tainted upon module load. Therefore,
> > we're removing this call and relying on the KUnit framework to taint the
> > kernel or not.
> >
> > Signed-off-by: Joe Fradley <joefradley@google.com>
> > ---
>
> Thanks!
>
> This definitely fixes an assumption I'd had about KUnit-usage which
> definitely doesn't hold: that all KUnit tests would be in their own
> modules (or at least that those modules wouldn't need to be loaded on
> otherwise production systems). Given this isn't the case for a number
> of modules (thuderbolt, apparmor, probably soon amdgpu), it makles
> sense to get rid of this and only taint the kernel when the test is
> actually run, not just when it's loaded.
>
> This could be considered a fix for c272612cb4a2 ("kunit: Taint the
> kernel when KUnit tests are run"), as it'd already be possible to
> load, e.g., thunderbolt, but prevent the tests from executing with a
> filter glob which doesn't match any tests. That possibly shouldn't
> taint the kernel.

Great, thank you for the review.

>
> Reviewed-by: David Gow <davidgow@google.com>
> Fixes: c272612cb4a2 ("kunit: Taint the kernel when KUnit tests are run")
>
> Cheers,
> -- David
>
> >  include/kunit/test.h | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/include/kunit/test.h b/include/kunit/test.h
> > index c958855681cc..f23d3954aa17 100644
> > --- a/include/kunit/test.h
> > +++ b/include/kunit/test.h
> > @@ -251,7 +251,6 @@ static inline int kunit_run_all_tests(void)
> >  #endif /* IS_BUILTIN(CONFIG_KUNIT) */
> >
> >  #define __kunit_test_suites(unique_array, ...)                                \
> > -       MODULE_INFO(test, "Y");                                                \
> >         static struct kunit_suite *unique_array[]                              \
> >         __aligned(sizeof(struct kunit_suite *))                                \
> >         __used __section(".kunit_test_suites") = { __VA_ARGS__ }
> > --
> > 2.37.1.595.g718a3a8f04-goog
> >