Re: [PATCH v4] selftests/vm: fix errno handling in mrelease_test

[David Vernet <void@manifault.com>]

On Wed, Jul 06, 2022 at 04:16:02PM +0200, Adam Sindelar wrote:
> mrelease_test should return KSFT_SKIP when process_mrelease is not
> defined, but due to a perror call consuming the errno, it returns
> KSFT_FAIL.
> 
> This patch decides the exit codes before calling perror.
> 
> Fixes: 33776141b812 ("selftests: vm: add process_mrelease tests")
> 
> Signed-off-by: Adam Sindelar <adam@wowsignal.io>
> ---
> v1->v2: Fixed second instance in the same file
> v2->v3: Fixed remaining instances of errno mishandling
> v3->v4: Added a "Fixes:" line for the log
> 
>  tools/testing/selftests/vm/mrelease_test.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/testing/selftests/vm/mrelease_test.c b/tools/testing/selftests/vm/mrelease_test.c
> index 96671c2f7d48..6c62966ab5db 100644
> --- a/tools/testing/selftests/vm/mrelease_test.c
> +++ b/tools/testing/selftests/vm/mrelease_test.c
> @@ -62,19 +62,22 @@ static int alloc_noexit(unsigned long nr_pages, int pipefd)
>  /* The process_mrelease calls in this test are expected to fail */
>  static void run_negative_tests(int pidfd)
>  {
> +	int res;
>  	/* Test invalid flags. Expect to fail with EINVAL error code. */
>  	if (!syscall(__NR_process_mrelease, pidfd, (unsigned int)-1) ||
>  			errno != EINVAL) {
> +		res = (errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
>  		perror("process_mrelease with wrong flags");
> -		exit(errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
> +		exit(res);
>  	}
>  	/*
>  	 * Test reaping while process is alive with no pending SIGKILL.
>  	 * Expect to fail with EINVAL error code.
>  	 */
>  	if (!syscall(__NR_process_mrelease, pidfd, 0) || errno != EINVAL) {
> +		res = (errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
>  		perror("process_mrelease on a live process");
> -		exit(errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
> +		exit(res);
>  	}
>  }
>  
> @@ -100,8 +103,9 @@ int main(void)
>  
>  	/* Test a wrong pidfd */
>  	if (!syscall(__NR_process_mrelease, -1, 0) || errno != EBADF) {
> +		res = (errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
>  		perror("process_mrelease with wrong pidfd");
> -		exit(errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
> +		exit(res);
>  	}
>  
>  	/* Start the test with 1MB child memory allocation */
> @@ -156,8 +160,9 @@ int main(void)
>  	run_negative_tests(pidfd);
>  
>  	if (kill(pid, SIGKILL)) {
> +		res = (errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
>  		perror("kill");
> -		exit(errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
> +		exit(res);
>  	}
>  
>  	success = (syscall(__NR_process_mrelease, pidfd, 0) == 0);
> @@ -172,9 +177,10 @@ int main(void)
>  		if (errno == ESRCH) {
>  			retry = (size <= MAX_SIZE_MB);
>  		} else {
> +			res = (errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
>  			perror("process_mrelease");
>  			waitpid(pid, NULL, 0);
> -			exit(errno == ENOSYS ? KSFT_SKIP : KSFT_FAIL);
> +			exit(res);
>  		}
>  	}
>  
> -- 
> 2.35.1
> 

Thanks, Adam. Looks great.

Reviewed-by: David Vernet <void@manifault.com>