selftests/mm: fix two -Wformat-security warnings in uffd builds

The uffd tests generate two compile time warnings from clang's
-Wformat-security setting. These trigger at the call sites for
uffd_test_start() and uffd_test_skip().

1) Fix the uffd_test_start() issue by removing the intermediate
test_name variable (thanks to David Hildenbrand for showing how to do
this).

2) Fix the uffd_test_skip() issue by observing that there is no need for
a macro and a variable args approach, because all callers of
uffd_test_skip() pass in a simple char* string, without any format
specifiers. So just change uffd_test_skip() into a regular C function.

Link: https://lkml.kernel.org/r/20230606071637.267103-7-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c
index 269c867..04d91f1 100644 (file)
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -109,12 +109,11 @@ static void uffd_test_pass(void)
                ksft_inc_fail_cnt();            \
        } while (0)
 
-#define  uffd_test_skip(...)  do {             \
-               printf("skipped [reason: ");    \
-               printf(__VA_ARGS__);            \
-               printf("]\n");                  \
-               ksft_inc_xskip_cnt();           \
-       } while (0)
+static void uffd_test_skip(const char *message)
+{
+       printf("skipped [reason: %s]\n", message);
+       ksft_inc_xskip_cnt();
+}
 
 /*
  * Returns 1 if specific userfaultfd supported, 0 otherwise.  Note, we'll
@@ -1149,7 +1148,6 @@ int main(int argc, char *argv[])
        uffd_test_case_t *test;
        mem_type_t *mem_type;
        uffd_test_args_t args;
-       char test_name[128];
        const char *errmsg;
        int has_uffd, opt;
        int i, j;
@@ -1192,10 +1190,8 @@ int main(int argc, char *argv[])
                        mem_type = &mem_types[j];
                        if (!(test->mem_targets & mem_type->mem_flag))
                                continue;
-                       snprintf(test_name, sizeof(test_name),
-                                "%s on %s", test->name, mem_type->name);
 
-                       uffd_test_start(test_name);
+                       uffd_test_start("%s on %s", test->name, mem_type->name);
                        if (!uffd_feature_supported(test)) {
                                uffd_test_skip("feature missing");
                                continue;