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Date: Fri, 28 Feb 2025 22:50:07 +0530
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Subject: Re: [PATCH v3 02/10] selftests/mm: Skip uffd-stress if userfaultfd
 not available
To: Brendan Jackman <jackmanb@google.com>,
 Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
 Andrew Morton <akpm@linux-foundation.org>, Shuah Khan <shuah@kernel.org>
Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
 linux-kernel@vger.kernel.org
References: <20250228-mm-selftests-v3-0-958e3b6f0203@google.com>
 <20250228-mm-selftests-v3-2-958e3b6f0203@google.com>
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From: Dev Jain <dev.jain@arm.com>
In-Reply-To: <20250228-mm-selftests-v3-2-958e3b6f0203@google.com>
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On 28/02/25 10:24 pm, Brendan Jackman wrote:
> It's pretty obvious that the test wouldn't work if you don't have the
> feature enabled. But, it's still useful to SKIP instead of failing so
> the reader can immediately tell that this is the reason why.
> 
> Signed-off-by: Brendan Jackman <jackmanb@google.com>
> ---
>   tools/testing/selftests/mm/uffd-stress.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
> index a4b83280998ab7ce8d31e91d8f9fbb47ef11d742..ed68436fac62c76e2ca7060c661487f2f8a6ab45 100644
> --- a/tools/testing/selftests/mm/uffd-stress.c
> +++ b/tools/testing/selftests/mm/uffd-stress.c
> @@ -411,8 +411,8 @@ static void parse_test_type_arg(const char *raw_type)
>   	 * feature.
>   	 */
>   
> -	if (uffd_get_features(&features))
> -		err("failed to get available features");
> +	if (uffd_get_features(&features) && errno == ENOENT)
> +		ksft_exit_skip("failed to get available features (%d)\n", errno);

Is it possible that uffd_get_features(&features) returns non-zero 
without errno == ENOENT?