userfaultfd/selftests: hint the test runner on required privilege
Now userfaultfd test program requires either root or ptrace privilege due
to the signal/event tests. When UFFDIO_API failed, hint the test runner
about this fact verbosely.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Peter Xu <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Mike Rapoport <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 6e482e2..9d8650d 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -794,7 +794,8 @@ 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");
+ fprintf(stderr, "UFFDIO_API failed.\nPlease make sure to "
+ "run with either root or ptrace capability.\n");
return 1;
}
if (uffdio_api.api != UFFD_API) {
