Re: [PATCH 2/3] userfaultfd: selftest: Skip test if a feature isn't supported

From: Mike Rapoport
Date: Wed Jul 25 2018 - 10:12:59 EST


Hi,

On Tue, Jul 24, 2018 at 11:42:08PM -0300, Thiago Jung Bauermann wrote:
> If userfaultfd runs on a system that doesn't support some feature it is
> trying to test, it currently ends with error code 1 which indicates
> test failure:
>
> # ./userfaultfd anon 10 10
> nr_pages: 160, nr_pages_per_cpu: 80
> bounces: 9, mode: rnd poll, userfaults: 7 59
> bounces: 8, mode: poll, userfaults: 0 0
> bounces: 7, mode: rnd racing ver, userfaults: 45 2
> bounces: 6, mode: racing ver, userfaults: 3 1
> bounces: 5, mode: rnd ver, userfaults: 55 32
> bounces: 4, mode: ver, userfaults: 69 0
> bounces: 3, mode: rnd racing, userfaults: 1 1
> bounces: 2, mode: racing, userfaults: 65 0
> bounces: 1, mode: rnd, userfaults: 44 1
> bounces: 0, mode:, userfaults: 3 2
> testing UFFDIO_ZEROPAGE: done.
> testing signal delivery: UFFDIO_API
> # echo $?
> 1
>
> Make the testcase return KSFT_SKIP instead, which is more accurate since it
> is not a real test failure:
>
> # ./userfaultfd anon 10 10
> nr_pages: 160, nr_pages_per_cpu: 80
> bounces: 9, mode: rnd poll, userfaults: 3 0
> bounces: 8, mode: poll, userfaults: 6 1
> bounces: 7, mode: rnd racing ver, userfaults: 3 1
> bounces: 6, mode: racing ver, userfaults: 2 1
> bounces: 5, mode: rnd ver, userfaults: 2 1
> bounces: 4, mode: ver, userfaults: 3 47
> bounces: 3, mode: rnd racing, userfaults: 38 0
> bounces: 2, mode: racing, userfaults: 4 61
> bounces: 1, mode: rnd, userfaults: 16 6
> bounces: 0, mode:, userfaults: 55 25
> testing UFFDIO_ZEROPAGE: done.
> testing signal delivery: UFFDIO_API: Invalid argument
> # echo $?
> 4
>
> While at it, also improve the error message of the ioctl(UFFDIO_API) call.

Can you please also make the test return KSFT_SKIP if userfaultfd(2) fails
with ENOSYS?

> Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx>
> ---
> tools/testing/selftests/vm/userfaultfd.c | 41 ++++++++++++++++++++++----------
> 1 file changed, 29 insertions(+), 12 deletions(-)
>
> diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
> index e4099afe7557..bc9ec38fbc34 100644
> --- a/tools/testing/selftests/vm/userfaultfd.c
> +++ b/tools/testing/selftests/vm/userfaultfd.c
> @@ -645,8 +645,11 @@ static int userfaultfd_open(int features)
> uffdio_api.api = UFFD_API;
> uffdio_api.features = features;
> if (ioctl(uffd, UFFDIO_API, &uffdio_api)) {
> - fprintf(stderr, "UFFDIO_API\n");
> - return 1;
> + int errnum = errno;
> +
> + perror("UFFDIO_API");
> +
> + return errnum == EINVAL ? KSFT_SKIP : 1;
> }
> if (uffdio_api.api != UFFD_API) {
> fprintf(stderr, "UFFDIO_API error %Lu\n", uffdio_api.api);
> @@ -852,6 +855,7 @@ static int userfaultfd_zeropage_test(void)
> {
> struct uffdio_register uffdio_register;
> unsigned long expected_ioctls;
> + int err;
>
> printf("testing UFFDIO_ZEROPAGE: ");
> fflush(stdout);
> @@ -859,8 +863,10 @@ static int userfaultfd_zeropage_test(void)
> if (uffd_test_ops->release_pages(area_dst))
> return 1;
>
> - if (userfaultfd_open(0))
> - return 1;
> + err = userfaultfd_open(0);
> + if (err)
> + return err;
> +
> uffdio_register.range.start = (unsigned long) area_dst;
> uffdio_register.range.len = nr_pages * page_size;
> uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
> @@ -902,8 +908,9 @@ static int userfaultfd_events_test(void)
>
> features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
> UFFD_FEATURE_EVENT_REMOVE;
> - if (userfaultfd_open(features))
> - return 1;
> + err = userfaultfd_open(features);
> + if (err)
> + return err;
> fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
>
> uffdio_register.range.start = (unsigned long) area_dst;
> @@ -961,8 +968,9 @@ static int userfaultfd_sig_test(void)
> return 1;
>
> features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
> - if (userfaultfd_open(features))
> - return 1;
> + err = userfaultfd_open(features);
> + if (err)
> + return err;
> fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
>
> uffdio_register.range.start = (unsigned long) area_dst;
> @@ -1027,8 +1035,9 @@ static int userfaultfd_stress(void)
> if (!area_dst)
> return 1;
>
> - if (userfaultfd_open(0))
> - return 1;
> + err = userfaultfd_open(0);
> + if (err)
> + return err;
>
> count_verify = malloc(nr_pages * sizeof(unsigned long long));
> if (!count_verify) {
> @@ -1199,8 +1208,16 @@ static int userfaultfd_stress(void)
> return err;
>
> close(uffd);
> - return userfaultfd_zeropage_test() || userfaultfd_sig_test()
> - || userfaultfd_events_test();
> +
> + err = userfaultfd_zeropage_test();
> + if (err)
> + return err;
> +
> + err = userfaultfd_sig_test();
> + if (err)
> + return err;
> +
> + return userfaultfd_events_test();
> }
>
> /*

--
Sincerely yours,
Mike.