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From:   Brendan Higgins <brendanhiggins@google.com>
Date:   Tue, 17 May 2022 16:45:00 -0400
Message-ID: <CAFd5g46dQ=q5UuXaoXwh32kjGoFi0m59L-frm6T5Xcwo81m0Hg@mail.gmail.com>
Subject: Re: [PATCH v3 1/3] panic: Taint kernel if tests are run
To:     David Gow <davidgow@google.com>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Luis Chamberlain <mcgrof@kernel.org>,
        "Guilherme G . Piccoli" <gpiccoli@igalia.com>,
        Sebastian Reichel <sre@kernel.org>,
        John Ogness <john.ogness@linutronix.de>,
        Joe Fradley <joefradley@google.com>,
        Daniel Latypov <dlatypov@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>,
        Lucas De Marchi <lucas.demarchi@intel.com>,
        Aaron Tomlin <atomlin@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org
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On Fri, May 13, 2022 at 4:32 AM David Gow <davidgow@google.com> wrote:
>
> Most in-kernel tests (such as KUnit tests) are not supposed to run on
> production systems: they may do deliberately illegal things to trigger
> errors, and have security implications (for example, KUnit assertions
> will often deliberately leak kernel addresses).
>
> Add a new taint type, TAINT_TEST to signal that a test has been run.
> This will be printed as 'N' (originally for kuNit, as every other
> sensible letter was taken.)
>
> This should discourage people from running these tests on production
> systems, and to make it easier to tell if tests have been run
> accidentally (by loading the wrong configuration, etc.)
>
> Signed-off-by: David Gow <davidgow@google.com>

Aside from Luis' comment (which I agree with), this looks good. I am
not an expert on the taint mechanism, but this seems pretty
straightforward.

Reviewed-by: Brendan Higgins <brendanhiggins@google.com>