[1/6] selftests/mm: Report errno when things fail

Just reporting failure doesn't tell you what went wrong. This can fail
in different ways so report errno to help the reader get started
debugging.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
 tools/testing/selftests/mm/gup_longterm.c | 32 +++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

On 20/02/25 8:33 pm, Brendan Jackman wrote:
> Just reporting failure doesn't tell you what went wrong. This can fail
> in different ways so report errno to help the reader get started
> debugging.

IMHO it would be even better if we reported strerror(errno).

> 
> Signed-off-by: Brendan Jackman <jackmanb@google.com>
> ---
>   tools/testing/selftests/mm/gup_longterm.c | 32 +++++++++++++++----------------
>   1 file changed, 16 insertions(+), 16 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/gup_longterm.c b/tools/testing/selftests/mm/gup_longterm.c
> index 9423ad439a6140163bdef2974615bb86406a8c14..46a2139b3a646f6c050eb031a770f615be76c433 100644
> --- a/tools/testing/selftests/mm/gup_longterm.c
> +++ b/tools/testing/selftests/mm/gup_longterm.c
> @@ -96,13 +96,13 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared)
>   	int ret;
>   
>   	if (ftruncate(fd, size)) {
> -		ksft_test_result_fail("ftruncate() failed\n");
> +		ksft_test_result_fail("ftruncate() failed (%d)\n", errno);
>   		return;
>   	}
>   
>   	if (fallocate(fd, 0, 0, size)) {
>   		if (size == pagesize)
> -			ksft_test_result_fail("fallocate() failed\n");
> +			ksft_test_result_fail("fallocate() failed (%d)\n", errno);
>   		else
>   			ksft_test_result_skip("need more free huge pages\n");
>   		return;
> @@ -112,7 +112,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared)
>   		   shared ? MAP_SHARED : MAP_PRIVATE, fd, 0);
>   	if (mem == MAP_FAILED) {
>   		if (size == pagesize || shared)
> -			ksft_test_result_fail("mmap() failed\n");
> +			ksft_test_result_fail("mmap() failed (%d)\n", errno);
>   		else
>   			ksft_test_result_skip("need more free huge pages\n");
>   		return;
> @@ -130,7 +130,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared)
>   		 */
>   		ret = mprotect(mem, size, PROT_READ);
>   		if (ret) {
> -			ksft_test_result_fail("mprotect() failed\n");
> +			ksft_test_result_fail("mprotect() failed (%d)\n", errno);
>   			goto munmap;
>   		}
>   		/* FALLTHROUGH */
> @@ -165,18 +165,18 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared)
>   		args.flags |= rw ? PIN_LONGTERM_TEST_FLAG_USE_WRITE : 0;
>   		ret = ioctl(gup_fd, PIN_LONGTERM_TEST_START, &args);
>   		if (ret && errno == EINVAL) {
> -			ksft_test_result_skip("PIN_LONGTERM_TEST_START failed\n");
> +			ksft_test_result_skip("PIN_LONGTERM_TEST_START failed (EINVAL)n");
>   			break;
>   		} else if (ret && errno == EFAULT) {
>   			ksft_test_result(!should_work, "Should have failed\n");
>   			break;
>   		} else if (ret) {
> -			ksft_test_result_fail("PIN_LONGTERM_TEST_START failed\n");
> +			ksft_test_result_fail("PIN_LONGTERM_TEST_START failed (%d)\n", errno);
>   			break;
>   		}
>   
>   		if (ioctl(gup_fd, PIN_LONGTERM_TEST_STOP))
> -			ksft_print_msg("[INFO] PIN_LONGTERM_TEST_STOP failed\n");
> +			ksft_print_msg("[INFO] PIN_LONGTERM_TEST_STOP failed (%d)\n", errno);
>   
>   		/*
>   		 * TODO: if the kernel ever supports long-term R/W pinning on
> @@ -202,7 +202,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared)
>   		/* Skip on errors, as we might just lack kernel support. */
>   		ret = io_uring_queue_init(1, &ring, 0);
>   		if (ret < 0) {
> -			ksft_test_result_skip("io_uring_queue_init() failed\n");
> +			ksft_test_result_skip("io_uring_queue_init() failed (%d)\n", errno);
>   			break;
>   		}
>   		/*
> @@ -215,13 +215,13 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared)
>   		/* Only new kernels return EFAULT. */
>   		if (ret && (errno == ENOSPC || errno == EOPNOTSUPP ||
>   			    errno == EFAULT)) {
> -			ksft_test_result(!should_work, "Should have failed\n");
> +			ksft_test_result(!should_work, "Should have failed (%d)\n", errno);
>   		} else if (ret) {
>   			/*
>   			 * We might just lack support or have insufficient
>   			 * MEMLOCK limits.
>   			 */
> -			ksft_test_result_skip("io_uring_register_buffers() failed\n");
> +			ksft_test_result_skip("io_uring_register_buffers() failed (%d)\n", errno);
>   		} else {
>   			ksft_test_result(should_work, "Should have worked\n");
>   			io_uring_unregister_buffers(&ring);
> @@ -249,7 +249,7 @@ static void run_with_memfd(test_fn fn, const char *desc)
>   
>   	fd = memfd_create("test", 0);
>   	if (fd < 0) {
> -		ksft_test_result_fail("memfd_create() failed\n");
> +		ksft_test_result_fail("memfd_create() failed (%d)\n", errno);
>   		return;
>   	}
>   
> @@ -266,13 +266,13 @@ static void run_with_tmpfile(test_fn fn, const char *desc)
>   
>   	file = tmpfile();
>   	if (!file) {
> -		ksft_test_result_fail("tmpfile() failed\n");
> +		ksft_test_result_fail("tmpfile() failed (%d)\n", errno);
>   		return;
>   	}
>   
>   	fd = fileno(file);
>   	if (fd < 0) {
> -		ksft_test_result_fail("fileno() failed\n");
> +		ksft_test_result_fail("fileno() failed (%d)\n", errno);
>   		goto close;
>   	}
>   
> @@ -290,12 +290,12 @@ static void run_with_local_tmpfile(test_fn fn, const char *desc)
>   
>   	fd = mkstemp(filename);
>   	if (fd < 0) {
> -		ksft_test_result_fail("mkstemp() failed\n");
> +		ksft_test_result_fail("mkstemp() failed (%d)\n", errno);
>   		return;
>   	}
>   
>   	if (unlink(filename)) {
> -		ksft_test_result_fail("unlink() failed\n");
> +		ksft_test_result_fail("unlink() failed (%d)\n", errno);
>   		goto close;
>   	}
>   
> @@ -317,7 +317,7 @@ static void run_with_memfd_hugetlb(test_fn fn, const char *desc,
>   
>   	fd = memfd_create("test", flags);
>   	if (fd < 0) {
> -		ksft_test_result_skip("memfd_create() failed\n");
> +		ksft_test_result_skip("memfd_create() failed (%d)\n", errno);
>   		return;
>   	}
>   
>