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

[Andrew Jones]

On Wed, Dec 04, 2024 at 06:57:10PM -0800, 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;
> +	}

Could make a wrapper function for pwrite() to avoid duplicating the ret
value check.

> +
> +	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL,
> +			 "sysctl disabled\n");

Why is this changed from expecting 0 for the return and being the
"sysctrl enabled" test? We still write '0' to tagged_addr_disabled here.

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

Not part of this patch, but now that I looked at
test_tagged_addr_abi_sysctl() I see that
ksft_test_result_skip() is duplicated.

Thanks,
drew

> 
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