linux-kernel - Re: [PATCH] kunit: make FAULT_TEST default to n when PANIC_ON

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Message-ID: <CABVgOSk4bBLXsB455u-2gBhDKuU=czVNLax0ep2gHw_ajVbE=Q@mail.gmail.com>
Date: Wed, 10 Dec 2025 16:16:26 +0800
From: David Gow <davidgow@...gle.com>
To: Brendan Jackman <jackmanb@...gle.com>
Cc: Brendan Higgins <brendan.higgins@...ux.dev>, Rae Moar <rmoar@...gle.com>, 
	linux-kselftest@...r.kernel.org, kunit-dev@...glegroups.com, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kunit: make FAULT_TEST default to n when PANIC_ON_OOPS

On Sun, 7 Dec 2025 at 10:17, Brendan Jackman <jackmanb@...gle.com> wrote:
>
> As describe in the help string, the user might want to disable these
> tests if they don't like to see stacktraces/BUG etc in their kernel log.
>
> However, if they enable PANIC_ON_OOPS, these tests also crash the
> machine, which it's safe to assume _almost_ nobody wants.
>
> One might argue that _absolutely_ nobody ever wants their kernel to
> crash so this should just be a hard dependency instead of a default.
> However, since this is rather special code that's anyway concerned with
> deliberately doing "bad" things, the normal rules don't seem to apply,
> hence prefer flexibility and allow users to set up a crashing Kconfig if
> they so choose.
>
> Signed-off-by: Brendan Jackman <jackmanb@...gle.com>
> ---

I like this compromise: I think there are still some cases where we
would want PANIC_ON_OOPS + faulting tests, particularly if you're
splitting the test execution over several boots (e.g. --run_isolated),
but it's got to be vanishingly rare.

So this is an excellent default.

Reviewed-by: David Gow <davidgow@...gle.com>

Cheers,
-- David

>  lib/kunit/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/kunit/Kconfig b/lib/kunit/Kconfig
> index 50ecf55d2b9c8a82f2aff7a0b4156bd6179b0a2f..498cc51e493dc9a819e012b8082fb765f25512b9 100644
> --- a/lib/kunit/Kconfig
> +++ b/lib/kunit/Kconfig
> @@ -28,7 +28,7 @@ config KUNIT_FAULT_TEST
>         bool "Enable KUnit tests which print BUG stacktraces"
>         depends on KUNIT_TEST
>         depends on !UML
> -       default y
> +       default !PANIC_ON_OOPS
>         help
>           Enables fault handling tests for the KUnit framework. These tests may
>           trigger a kernel BUG(), and the associated stack trace, even when they
>
> ---
> base-commit: 7bc16e72ddb993d706f698c2f6cee694e485f557
> change-id: 20251207-kunit-fault-no-panic-e9bdce848031
>
> Best regards,
> --
> Brendan Jackman <jackmanb@...gle.com>
>

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