selftests/harness: Handle TEST_F()'s explicit exit codes

If TEST_F() explicitly calls exit(code) with code different than 0, then
_metadata->exit_code is set to this code (e.g. KVM_ONE_VCPU_TEST()).  We
need to keep in mind that _metadata->exit_code can be KSFT_SKIP while
the process exit code is 0.

Cc: Jakub Kicinski <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Will Drewry <[email protected]>
Reported-by: Sean Christopherson <[email protected]>
Tested-by: Sean Christopherson <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 0710a1a ("selftests/harness: Merge TEST_F_FORK() into TEST_F()")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mickaël Salaün <[email protected]>

Author: l0kod

tools/testing/selftests/kselftest_harness.h

@@ -462,9 +462,13 @@ static inline pid_t clone3_vfork(void)
 		munmap(teardown, sizeof(*teardown)); \
 		if (self && fixture_name##_teardown_parent) \
 			munmap(self, sizeof(*self)); \
-		if (!WIFEXITED(status) && WIFSIGNALED(status)) \
+		if (WIFEXITED(status)) { \
+			if (WEXITSTATUS(status)) \
+				_metadata->exit_code = WEXITSTATUS(status); \
+		} else if (WIFSIGNALED(status)) { \
 			/* Forward signal to __wait_for_test(). */ \
 			kill(getpid(), WTERMSIG(status)); \
+		} \
 		__test_check_assert(_metadata); \
 	} \
 	static struct __test_metadata *_##fixture_name##_##test_name##_object; \