userfaultfd: selftest: explicit failure if the SIGBUS test failed

Showing zero in the output isn't very self explanatory as a successful
result.  Show a more explicit error output if the test fails.

Link: http://lkml.kernel.org/r/20170802165145.22628-4-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Alexey Perevalov <a.perevalov@samsung.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 4549ae4..a2c53a3 100644 (file)
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -987,7 +987,9 @@ static int userfaultfd_sig_test(void)
                return 1;
 
        printf("done.\n");
-       printf(" Signal test userfaults: %ld\n", userfaults);
+       if (userfaults)
+               fprintf(stderr, "Signal test failed, userfaults: %ld\n",
+                       userfaults);
        close(uffd);
        return userfaults != 0;
 }