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@linux.ibm.com

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();

}

/*

Mike Rapoport rppt@linux.vnet.ibm.com writes:

Hi,

On Tue, Jul 24, 2018 at 11:42:09PM -0300, Thiago Jung Bauermann wrote:

...

If userfaultfd runs on a system that doesn't support UFFDIO_ZEROPAGE for shared memory, it currently ends with error code 1 which indicates test failure:

# ./userfaultfd shmem 10 10 nr_pages: 160, nr_pages_per_cpu: 80 bounces: 9, mode: rnd poll, unexpected missing ioctl for anon memory # echo $? 1

This is a real failure, but expected so signal that to the test harness:

I don't think its a real failure. If the kernel does not support UFFDIO_ZEROPAGE for shared memory the userfaultfd_zeropage_test can be simply skipped.

Ok, good point. I'll make that change in v2.

...

# ./userfaultfd shmem 10 10 nr_pages: 160, nr_pages_per_cpu: 80 bounces: 9, mode: rnd poll, UFFDIO_ZEROPAGE unsupported in shmem VMAs # echo $? 2

Signed-off-by: Thiago Jung Bauermann bauerman@linux.ibm.com

tools/testing/selftests/vm/userfaultfd.c | 8 ++++++++ 1 file changed, 8 insertions(+)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index bc9ec38fbc34..686fe96f617f 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -1115,6 +1115,14 @@ static int userfaultfd_stress(void) expected_ioctls = uffd_test_ops->expected_ioctls; if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls) {

• 	if (test_type == TEST_SHMEM &&
  

• 	    (uffdio_register.ioctls & expected_ioctls) ==
  

• 	    UFFD_API_RANGE_IOCTLS_BASIC) {
  

• 		fprintf(stderr,
  

• 			"UFFDIO_ZEROPAGE unsupported in shmem VMAs\n");
  

• 		return KSFT_XFAIL;
  

• 	}
  

By all means, this check should be moved to userfaultfd_zeropage_test().

I made that change in v2.

Ideally, we should call here ksft_test_result_skip() and simply return from the function.

In my understanding, calling ksft_test_result_skip() would require converting the testcase to use the functions that generate TAP output.

Also, returning here isn't actually necessary: from my testing userfaultfd_stress() doesn't require zeropage support in shmem so if the only bit missing from uffdio_register.ioctls is the one for UFFDIO_ZEROPAGE then this error can simply be ignored and the test can continue. Do you agree?

...

	fprintf(stderr,
		"unexpected missing ioctl for anon memory\n");
	return 1;

-- Thiago Jung Bauermann IBM Linux Technology Center

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