Re: [PATCH v2 1/2] selftests: mm: ksm: Fix incorrect evaluation of parameter

From: Stefan Roesch <shr@devkernel.io>
To: Ayush Jain <ayush.jain3@amd.com>
Cc: akpm@linux-foundation.org, shuah@kernel.org,
	pasha.tatashin@soleen.com, zhansayabagdaulet@gmail.com,
	tyhicks@linux.microsoft.com, raghavendra.kt@amd.com,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
	linux-kernel@vger.kernel.org, Narasimhan.V@amd.com,
	Santosh.Shukla@amd.com, David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH v2 1/2] selftests: mm: ksm: Fix incorrect evaluation of parameter
Date: Tue, 08 Aug 2023 10:31:24 -0700	[thread overview]
Message-ID: <qvqwfs4tphip.fsf@devbig1114.prn1.facebook.com> (raw)
In-Reply-To: <20230728163952.4634-1-ayush.jain3@amd.com>

Ayush Jain <ayush.jain3@amd.com> writes:

> A missing break in kms_tests leads to kselftest hang when the
> parameter -s is used.
> In current code flow because of missing break in -s, -t parses
> args spilled from -s and as -t accepts only valid values as 0,1
> so any arg in -s >1 or <0, gets in ksm_test failure
>
> This went undetected since, before the addition of option -t,
> the next case -M would immediately break out of the switch
> statement but that is no longer the case
>
> Add the missing break statement.
>
> ----Before----
> ./ksm_tests -H -s 100
> Invalid merge type
>
> ----After----
> ./ksm_tests -H -s 100
> Number of normal pages:    0
> Number of huge pages:    50
> Total size:    100 MiB
> Total time:    0.401732682 s
> Average speed:  248.922 MiB/s
>
> Fixes: 07115fcc15b4 ("selftests/mm: add new selftests for KSM")
>
> Signed-off-by: Ayush Jain <ayush.jain3@amd.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> ---
> v1 -> v2
> collect Reviewed-by from David
> Updated Fixes tag from commit 9e7cb94ca218 to 07115fcc15b4
>
>  tools/testing/selftests/mm/ksm_tests.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c
> index 435acebdc325..380b691d3eb9 100644
> --- a/tools/testing/selftests/mm/ksm_tests.c
> +++ b/tools/testing/selftests/mm/ksm_tests.c
> @@ -831,6 +831,7 @@ int main(int argc, char *argv[])
>  				printf("Size must be greater than 0\n");
>  				return KSFT_FAIL;
>  			}
> +			break;
>  		case 't':
>  			{
>  				int tmp = atoi(optarg);

Acked-by: Stefan Roesch <shr@devkernel.io>