[PATCH v3 4/4] userfaultfd: selftest: make supported range ioctl verification more robust

Thiago Jung Bauermann
2018-08-28T17:26:43Z

From: Mike Rapoport <rppt@linux.vnet.ibm.com>

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>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.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 c84e44ddf314..676cbedff3db 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;
@@ -856,7 +882,6 @@ static int uffdio_zeropage(int ufd, unsigned long offset)
static int userfaultfd_zeropage_test(void)
{
struct uffdio_register uffdio_register;
- unsigned long expected_ioctls;
int err;

printf("testing UFFDIO_ZEROPAGE: ");
@@ -875,12 +900,8 @@ 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))
@@ -895,7 +916,6 @@ 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;
@@ -922,12 +942,8 @@ 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);
@@ -957,7 +973,6 @@ 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;
@@ -982,12 +997,8 @@ 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);
@@ -1088,8 +1099,6 @@ static int userfaultfd_stress(void)

err = 0;
while (bounces--) {
- unsigned long expected_ioctls;
-
printf("bounces: %d, mode:", bounces);
if (bounces & BOUNCE_RANDOM)
printf(" rnd");
@@ -1115,13 +1124,9 @@ 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)