linux-kernel - Re: [PATCH 3/4] selftests/lkdtm: Reset WARN

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Message-ID: <a5808685-88bf-2e04-1973-a9dbdb23f5e3@linuxfoundation.org>
Date:   Fri, 29 May 2020 14:22:10 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     Kees Cook <keescook@...omium.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Prasad Sodagudi <psodagud@...eaurora.org>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Amit Daniel Kachhap <amit.kachhap@....com>,
        linux-kselftest@...r.kernel.org,
        clang-built-linux@...glegroups.com, linux-kernel@...r.kernel.org,
        Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH 3/4] selftests/lkdtm: Reset WARN_ONCE to avoid false
 negatives

On 5/29/20 2:03 PM, Kees Cook wrote:
> Since we expect to see warnings every time for many tests, just reset
> the WARN_ONCE flags each time the script runs.
> 
> Signed-off-by: Kees Cook <keescook@...omium.org>
> ---
>   tools/testing/selftests/lkdtm/run.sh | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/tools/testing/selftests/lkdtm/run.sh b/tools/testing/selftests/lkdtm/run.sh
> index ee64ff8df8f4..8383eb89d88a 100755
> --- a/tools/testing/selftests/lkdtm/run.sh
> +++ b/tools/testing/selftests/lkdtm/run.sh
> @@ -8,6 +8,7 @@
>   #
>   set -e
>   TRIGGER=/sys/kernel/debug/provoke-crash/DIRECT
> +CLEAR_ONCE=/sys/kernel/debug/clear_warn_once
>   KSELFTEST_SKIP_TEST=4
>   
>   # Verify we have LKDTM available in the kernel.
> @@ -67,6 +68,11 @@ cleanup() {
>   }
>   trap cleanup EXIT
>   
> +# Reset WARN_ONCE counters so we trip it each time this runs.
> +if [ -w $CLEAR_ONCE ] ; then
> +	echo 1 > $CLEAR_ONCE
> +fi
> +
>   # Save existing dmesg so we can detect new content below
>   dmesg > "$DMESG"
>   
> 

Acked-by: Shuah Khan <skhan@...uxfoundation.org>

thanks,
-- Shuah