Re: [PATCH 2/2] kunit: string: add strnlen SIZE_MAX test coverage

[Feng Jiang]

On 2026/7/22 14:40, Gao Rui wrote:
> Extend string_test_strnlen to validate strnlen behavior with
> SIZE_MAX input:
> 
> - Add explicit test case for strnlen(s, SIZE_MAX).
> - Ensure fallback to generic path returns correct length when
>   string has no NUL terminator.
> - Complements existing tests for non-terminated strings and
>   boundary conditions.
> 
> This improves KUnit coverage for extreme inputs and verifies
> the correctness of the new fallback logic in strnlen.S.
> 
> Signed-off-by: Gao Rui <gao.rui@xxxxxxxxxx>
> ---
>  lib/tests/string_kunit.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c
> index 0819ace5b027..8e2e8980aa75 100644
> --- a/lib/tests/string_kunit.c
> +++ b/lib/tests/string_kunit.c
> @@ -155,6 +155,16 @@ static void string_test_strnlen(struct kunit *test)
>  
>  	for (size_t offset = 0; offset < STRING_TEST_MAX_OFFSET; offset++) {
>  		for (size_t len = 0; len <= STRING_TEST_MAX_LEN; len++) {
> +			/* Test strings without NUL terminator */
> +			s = buf + buf_size - offset - len;
> +			if (len > 0)
> +				KUNIT_EXPECT_EQ(test, strnlen(s, len - 1), len - 1);
> +			if (len > 1)
> +				KUNIT_EXPECT_EQ(test, strnlen(s, len - 2), len - 2);
> +
> +			KUNIT_EXPECT_EQ(test, strnlen(s, len), len);
> +
> +			/* Test strings with NUL terminator */
>  			s = buf + buf_size - 1 - offset - len;
>  			s[len] = '\0';
>  
> @@ -169,6 +179,9 @@ static void string_test_strnlen(struct kunit *test)
>  			KUNIT_EXPECT_EQ(test, strnlen(s, len + 2), len);
>  			KUNIT_EXPECT_EQ(test, strnlen(s, len + 10), len);
>  
> +			/* Test Count overflow fallback */
> +			KUNIT_EXPECT_EQ(test, strnlen(s, SSIZE_MAX), len);
> +
>  			s[len] = 'A';
>  		}
>  	}

A similar patch has already been submitted:

https://lore.kernel.org/all/20260526085913.429049-1-min_halo@xxxxxxx/

-- 
With Best Regards,
Feng Jiang