Re: [PATCH v2] riscv: selftests: Fix warnings pointer masking test

[Alexandre Ghiti]

Hi Charlie,

On 05/12/2024 03:57, Charlie Jenkins wrote:
> When compiling the pointer masking tests with -Wall this warning
> is present:
>
> pointer_masking.c: In function ‘test_tagged_addr_abi_sysctl’:
> pointer_masking.c:203:9: warning: ignoring return value of ‘pwrite’
> declared with attribute ‘warn_unused_result’ [-Wunused-result]
>    203 |         pwrite(fd, &value, 1, 0); |
>        ^~~~~~~~~~~~~~~~~~~~~~~~ pointer_masking.c:208:9: warning:
> ignoring return value of ‘pwrite’ declared with attribute
> ‘warn_unused_result’ [-Wunused-result]
>    208 |         pwrite(fd, &value, 1, 0);
>
> I came across this on riscv64-linux-gnu-gcc (Ubuntu
> 11.4.0-1ubuntu1~22.04).
>
> Fix this by checking that the number of bytes written equal the expected
> number of bytes written.
>
> Fixes: 7470b5afd150 ("riscv: selftests: Add a pointer masking test")
> Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
> ---
> Changes in v2:
> - I had ret != 2 for testing, I changed it to be ret != 1.
> - Link to v1: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v1-1-ea1e9665ce7a@xxxxxxxxxxxx
> ---
>   tools/testing/selftests/riscv/abi/pointer_masking.c | 19 +++++++++++++++----
>   1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/riscv/abi/pointer_masking.c b/tools/testing/selftests/riscv/abi/pointer_masking.c
> index dee41b7ee3e3..229d85ccff50 100644
> --- a/tools/testing/selftests/riscv/abi/pointer_masking.c
> +++ b/tools/testing/selftests/riscv/abi/pointer_masking.c
> @@ -189,6 +189,7 @@ static void test_tagged_addr_abi_sysctl(void)
>   {
>   	char value;
>   	int fd;
> +	int ret;
>   
>   	ksft_print_msg("Testing tagged address ABI sysctl\n");
>   
> @@ -200,14 +201,24 @@ static void test_tagged_addr_abi_sysctl(void)
>   	}
>   
>   	value = '1';
> -	pwrite(fd, &value, 1, 0);
> +	ret = pwrite(fd, &value, 1, 0);
> +	if (ret != 1) {
> +		ksft_test_result_fail("Write to /proc/sys/abi/tagged_addr_disabled failed.\n");
> +		return;
> +	}
> +
>   	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL,
>   			 "sysctl disabled\n");
>   
>   	value = '0';
> -	pwrite(fd, &value, 1, 0);
> -	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == 0,
> -			 "sysctl enabled\n");
> +	ret = pwrite(fd, &value, 1, 0);
> +	if (ret != 1) {
> +		ksft_test_result_fail("Write to /proc/sys/abi/tagged_addr_disabled failed.\n");
> +		return;
> +	}
> +
> +	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL,
> +			 "sysctl disabled\n");

Why did you change the test from 0 to -EINVAL here?

Thanks,

Alex


>   
>   	set_tagged_addr_ctrl(0, false);
>   
>
> ---
> base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
> change-id: 20241204-fix_warnings_pointer_masking_tests-3860e4f35429