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From:   Daniel Latypov <dlatypov@google.com>
Date:   Wed, 4 May 2022 14:19:59 -0500
Message-ID: <CAGS_qxoFECVJD3Jby1eTWG741hBWuotuEM78PU-qfyvp-nLV7Q@mail.gmail.com>
Subject: Re: [PATCH v2] kunit: Taint kernel if any tests run
To:     Luis Chamberlain <mcgrof@kernel.org>
Cc:     David Gow <davidgow@google.com>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Lucas De Marchi <lucas.demarchi@intel.com>,
        Aaron Tomlin <atomlin@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        Brendan Higgins <brendanhiggins@google.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        "Guilherme G . Piccoli" <gpiccoli@igalia.com>,
        Sebastian Reichel <sre@kernel.org>,
        John Ogness <john.ogness@linutronix.de>,
        Joe Fradley <joefradley@google.com>,
        kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jani Nikula <jani.nikula@linux.intel.com>
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On Wed, May 4, 2022 at 1:46 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
> OK so, we can just skip tainting considerations for selftests which
> don't use modules for now. There may be selftests which do wonky
> things in userspace but indeed I agree the userspace taint would
> be better for those but I don't think it may be worth bother
> worrying about those at this point in time.
>
> But my point in that sharing a taint between kunit / selftests modules
> does make sense and is easily possible. The unfortunate aspect is just

Yes, I 100% agree that we should share a taint for kernelspace testing
from both kunit/kselftest.
Someone running the system won't care what framework was used.

> that selftests don't have a centralized runner, because I can just
> run tools/testing/selftests/sysctl/sysctl.sh for example and that's it.
> So I think we have no other option but to just add the module info
> manually for selftests at this time.

Somewhat tangential: there's a number of other test modules that
aren't explicitly part of kselftest.
Long-term, I think most of them should be converted to kselftest or
kunit as appropriate, so they'll get taken care of eventually.

A number of these modules depend on CONFIG_DEBUG_KERNEL=y, but we
can't pre-emptively set this new taint flag by checking for it as it's
too widely used :\
E.g. the debian-based distro I'm using right now has it set
$ grep 'CONFIG_DEBUG_KERNEL=y' /boot/config-$(uname -r)
CONFIG_DEBUG_KERNEL=y

-Daniel