Re: [PATCH] kasan: Enable KUnit integration whenever CONFIG_KUNIT is enabled

[Andrey Konovalov <andreyknvl@gmail.com>]

On Wed, Oct 19, 2022 at 10:58 AM 'David Gow' via kasan-dev
<kasan-dev@googlegroups.com> wrote:
>
> Enable the KASAN/KUnit integration even when the KASAN tests are
> disabled, as it's useful for testing other things under KASAN.
> Essentially, this reverts commit 49d9977ac909 ("kasan: check CONFIG_KASAN_KUNIT_TEST instead of CONFIG_KUNIT").
>
> To mitigate the performance impact slightly, add a likely() to the check
> for a currently running test.
>
> There's more we can do for performance if/when it becomes more of a
> problem, such as only enabling the "expect a KASAN failure" support wif
> the KASAN tests are enabled, or putting the whole thing behind a "kunit
> tests are running" static branch (which I do plan to do eventually).
>
> Fixes: 49d9977ac909 ("kasan: check CONFIG_KASAN_KUNIT_TEST instead of CONFIG_KUNIT")
> Signed-off-by: David Gow <davidgow@google.com>
> ---
>
> Basically, hiding the KASAN/KUnit integration broke being able to just
> pass --kconfig_add CONFIG_KASAN=y to kunit_tool to enable KASAN
> integration. We didn't notice this, because usually
> CONFIG_KUNIT_ALL_TESTS is enabled, which in turn enables
> CONFIG_KASAN_KUNIT_TEST. However, using a separate .kunitconfig might
> result in failures being missed.
>
> Take, for example:
> ./tools/testing/kunit/kunit.py run --kconfig_add CONFIG_KASAN=y \
>         --kunitconfig drivers/gpu/drm/tests
>
> This should run the drm tests with KASAN enabled, but even if there's a
> KASAN failure (such as the one fixed by [1]), kunit_tool will report
> success.

Hi David,

How does KUnit detect a KASAN failure for other tests than the KASAN
ones? I thought this was only implemented for KASAN tests. At least, I
don't see any code querying kunit_kasan_status outside of KASAN tests.

I'm currently switching KASAN tests from using KUnit resources to
console tracepoints [1], and those patches will be in conflict with
yours.

Thanks!

[1] https://lore.kernel.org/linux-mm/ebf96ea600050f00ed567e80505ae8f242633640.1666113393.git.andreyknvl@google.com/