On Fri, Aug 03, 2018 at 07:00:43PM -0300, Thiago Jung Bauermann wrote:

If the userfaultfd test is run on a kernel with CONFIG_USERFAULTFD=n, it will report that the system call is not available yet go ahead and continue anyway:

# ./userfaultfd anon 30 1 nr_pages: 480, nr_pages_per_cpu: 120 userfaultfd syscall not available in this kernel bounces: 0, mode:, register failure

This is because userfaultfd_open() returns 0 on success and 1 on error but all callers assume that it returns < 0 on error.

Since the convention of the test as a whole is the one used by userfault_open(), fix its callers instead. Now the test behaves correctly:

# ./userfaultfd anon 30 1 nr_pages: 480, nr_pages_per_cpu: 120 userfaultfd syscall not available in this kernel

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

Reviewed-by: Mike Rapoport rppt@linux.vnet.ibm.com

---

tools/testing/selftests/vm/userfaultfd.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index 7b8171e3128a..e4099afe7557 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -859,7 +859,7 @@ static int userfaultfd_zeropage_test(void) if (uffd_test_ops->release_pages(area_dst)) return 1;

• if (userfaultfd_open(0) < 0)

• if (userfaultfd_open(0)) return 1; uffdio_register.range.start = (unsigned long) area_dst; uffdio_register.range.len = nr_pages * page_size;

@@ -902,7 +902,7 @@ static int userfaultfd_events_test(void)

features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP | UFFD_FEATURE_EVENT_REMOVE;

• if (userfaultfd_open(features) < 0)

• if (userfaultfd_open(features)) return 1; fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);

@@ -961,7 +961,7 @@ static int userfaultfd_sig_test(void) return 1;

features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;

• if (userfaultfd_open(features) < 0)

• if (userfaultfd_open(features)) return 1; fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);

@@ -1027,7 +1027,7 @@ static int userfaultfd_stress(void) if (!area_dst) return 1;

• if (userfaultfd_open(0) < 0)

• if (userfaultfd_open(0)) return 1;

  count_verify = malloc(nr_pages * sizeof(unsigned long long));

On Fri, Aug 03, 2018 at 07:00:44PM -0300, Thiago Jung Bauermann wrote:

Since there's no point in doing anything in this case, immediately exit the process.

And take the opportunity to improve the error message.

Before:

# ./userfaultfd shmem 10 10 nr_pages: 160, nr_pages_per_cpu: 40 userfaultfd syscall not available in this kernel # echo $? 1

After:

# ./userfaultfd shmem 10 10 nr_pages: 160, nr_pages_per_cpu: 40 userfaultfd syscall not available in this kernel: Function not implemented # echo $? 4

Suggested-by: Mike Rapoport rppt@linux.vnet.ibm.com Signed-off-by: Thiago Jung Bauermann bauerman@linux.ibm.com

Acked-by: Mike Rapoport rppt@linux.vnet.ibm.com

---

tools/testing/selftests/vm/userfaultfd.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index e4099afe7557..d728bd1cb33c 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -636,9 +636,11 @@ static int userfaultfd_open(int features)

uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); if (uffd < 0) {

• fprintf(stderr,
  

• 	"userfaultfd syscall not available in this kernel\n");
  

• return 1;
  

• int errnum = errno;
  

• perror("userfaultfd syscall not available in this kernel");
  

• exit(errnum == ENOSYS ? KSFT_SKIP : 1);
  

  } uffd_flags = fcntl(uffd, F_GETFD, NULL);

On Fri, Aug 03, 2018 at 07:00:45PM -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 each test return KSFT_SKIP instead, which is more accurate since it is not a real test failure and try to run the other tests which may still work:

# ./userfaultfd anon 10 10 nr_pages: 160, nr_pages_per_cpu: 80 bounces: 9, mode: rnd poll, userfaults: 65 27 bounces: 8, mode: poll, userfaults: 0 0 bounces: 7, mode: rnd racing ver, userfaults: 60 29 bounces: 6, mode: racing ver, userfaults: 58 1 bounces: 5, mode: rnd ver, userfaults: 69 3 bounces: 4, mode: ver, userfaults: 35 27 bounces: 3, mode: rnd racing, userfaults: 44 0 bounces: 2, mode: racing, userfaults: 40 25 bounces: 1, mode: rnd, userfaults: 2 1 bounces: 0, mode:, userfaults: 0 1 testing UFFDIO_ZEROPAGE: done. testing signal delivery: UFFDIO_API: Invalid argument testing events (fork, remap, remove): userfaults: 160 # echo $? 0

While at it, also improve the error message of the ioctl(UFFDIO_API) call.

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

Acked-by: Mike Rapoport rppt@linux.vnet.ibm.com

---

tools/testing/selftests/vm/userfaultfd.c | 42 +++++++++++++++++++++++--------- 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index d728bd1cb33c..c84e44ddf314 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -647,8 +647,11 @@ 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);

@@ -854,6 +857,7 @@ static int userfaultfd_zeropage_test(void) { struct uffdio_register uffdio_register; unsigned long expected_ioctls;

• int err;

  printf("testing UFFDIO_ZEROPAGE: "); fflush(stdout);

@@ -861,8 +865,10 @@ 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;

@@ -904,8 +910,10 @@ 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;

@@ -963,8 +971,9 @@ 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;

@@ -1029,8 +1038,9 @@ 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) {

@@ -1201,8 +1211,16 @@ 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 && err != KSFT_SKIP)

• return err;
  

• err = userfaultfd_sig_test();
• if (err && err != KSFT_SKIP)

• return err;
  

• return userfaultfd_events_test();

}

/*

Hi,

On Fri, Aug 03, 2018 at 07:00:46PM -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

Change userfaultfd_zeropage_test() to return KSFT_SKIP to indicate that the test is being skipped.

I took a deeper look at what userfaultfd_zeropage_test() does and, apparently, I've mislead you. The test checks if the range has UFFDIO_ZEROPAGE and verifies that it works if yes; otherwise the test verifies that EINVAL is returned.

Can you please check if the patch below works in your environment?

From 7a34c84c0461b5073742275638c44b6535d19166 Mon Sep 17 00:00:00 2001

From: Mike Rapoport rppt@linux.vnet.ibm.com Date: Tue, 7 Aug 2018 09:44:19 +0300 Subject: [PATCH] userfaultfd: selftest: make supported range ioctl verification more robust

When userfaultfd tests runs on older kernel that does not support UFFDIO_ZEROPAGE for shared memory it fails at the ioctl verification.

Split out the verification that supported ioctls are superset of the expected ioctls and relax the checks for UFFDIO_ZEROPAGE for shared memory areas.

Signed-off-by: Mike Rapoport rppt@linux.vnet.ibm.com --- tools/testing/selftests/vm/userfaultfd.c | 63 +++++++++++++++++--------------- 1 file changed, 34 insertions(+), 29 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index 7b8171e3128a..a64bc38bc0e1 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -271,6 +271,32 @@ static int my_bcmp(char *str1, char *str2, size_t n) return 0; }

+static int verify_ioctls(unsigned long supported_ioctls) +{ + unsigned long expected_ioctls = uffd_test_ops->expected_ioctls; + + if ((supported_ioctls & expected_ioctls) == expected_ioctls) + return 0; + + /* + * For older kernels shared memory may not have UFFDIO_ZEROPAGE. + * In this case we just mask it out from the + * expected_ioctls. The userfaultfd_zeropage_test will then + * verify that an attempt to use UFFDIO_ZEROPAGE returns + * EINVAL + */ + if (test_type == TEST_SHMEM) { + expected_ioctls &= ~(1 << _UFFDIO_ZEROPAGE); + if ((supported_ioctls & expected_ioctls) == expected_ioctls) { + uffd_test_ops->expected_ioctls = expected_ioctls; + return 0; + } + } + + fprintf(stderr, "unexpected missing ioctl\n"); + return 1; +} + static void *locking_thread(void *arg) { unsigned long cpu = (unsigned long) arg; @@ -851,7 +877,6 @@ static int uffdio_zeropage(int ufd, unsigned long offset) static int userfaultfd_zeropage_test(void) { struct uffdio_register uffdio_register; - unsigned long expected_ioctls;

printf("testing UFFDIO_ZEROPAGE: "); fflush(stdout); @@ -867,12 +892,8 @@ static int userfaultfd_zeropage_test(void) if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) fprintf(stderr, "register failure\n"), exit(1);

- expected_ioctls = uffd_test_ops->expected_ioctls; - if ((uffdio_register.ioctls & expected_ioctls) != - expected_ioctls) - fprintf(stderr, - "unexpected missing ioctl for anon memory\n"), - exit(1); + if (verify_ioctls(uffdio_register.ioctls)) + return 1;

if (uffdio_zeropage(uffd, 0)) { if (my_bcmp(area_dst, zeropage, page_size)) @@ -887,7 +908,6 @@ static int userfaultfd_zeropage_test(void) static int userfaultfd_events_test(void) { struct uffdio_register uffdio_register; - unsigned long expected_ioctls; unsigned long userfaults; pthread_t uffd_mon; int err, features; @@ -912,12 +932,8 @@ static int userfaultfd_events_test(void) if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) fprintf(stderr, "register failure\n"), exit(1);

- expected_ioctls = uffd_test_ops->expected_ioctls; - if ((uffdio_register.ioctls & expected_ioctls) != - expected_ioctls) - fprintf(stderr, - "unexpected missing ioctl for anon memory\n"), - exit(1); + if (verify_ioctls(uffdio_register.ioctls)) + return 1;

if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, NULL)) perror("uffd_poll_thread create"), exit(1); @@ -947,7 +963,6 @@ static int userfaultfd_events_test(void) static int userfaultfd_sig_test(void) { struct uffdio_register uffdio_register; - unsigned long expected_ioctls; unsigned long userfaults; pthread_t uffd_mon; int err, features; @@ -971,12 +986,8 @@ static int userfaultfd_sig_test(void) if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) fprintf(stderr, "register failure\n"), exit(1);

- expected_ioctls = uffd_test_ops->expected_ioctls; - if ((uffdio_register.ioctls & expected_ioctls) != - expected_ioctls) - fprintf(stderr, - "unexpected missing ioctl for anon memory\n"), - exit(1); + if (verify_ioctls(uffdio_register.ioctls)) + return 1;

if (faulting_process(1)) fprintf(stderr, "faulting process failed\n"), exit(1); @@ -1076,8 +1087,6 @@ static int userfaultfd_stress(void)

err = 0; while (bounces--) { - unsigned long expected_ioctls; - printf("bounces: %d, mode:", bounces); if (bounces & BOUNCE_RANDOM) printf(" rnd"); @@ -1103,13 +1112,9 @@ static int userfaultfd_stress(void) fprintf(stderr, "register failure\n"); return 1; } - expected_ioctls = uffd_test_ops->expected_ioctls; - if ((uffdio_register.ioctls & expected_ioctls) != - expected_ioctls) { - fprintf(stderr, - "unexpected missing ioctl for anon memory\n"); + + if (verify_ioctls(uffdio_register.ioctls)) return 1; - }

if (area_dst_alias) { uffdio_register.range.start = (unsigned long)