[PATCH] selftests: fix build failure with NOLIBC

[Oleg Nesterov <oleg@redhat.com>]

As Mark explains ksft_min_kernel_version() can't be compiled with nolibc,
it doesn't implement uname().

Fixes: 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/all/f0523b3a-ea08-4615-b0fb-5b504a2d39df@sirena.org.uk/
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 tools/testing/selftests/kselftest.h           | 6 ++++++
 tools/testing/selftests/timers/posix_timers.c | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
index 973b18e156b2..0d9ed3255f5e 100644
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -392,6 +392,11 @@ static inline __printf(1, 2) int ksft_exit_skip(const char *msg, ...)
 static inline int ksft_min_kernel_version(unsigned int min_major,
 					  unsigned int min_minor)
 {
+#ifdef NOLIBC
+	ksft_print_msg("NOLIBC: Can't check kernel version: "
+			"Function not implemented\n");
+	return -1;
+#else
 	unsigned int major, minor;
 	struct utsname info;
 
@@ -399,6 +404,7 @@ static inline int ksft_min_kernel_version(unsigned int min_major,
 		ksft_exit_fail_msg("Can't parse kernel version\n");
 
 	return major > min_major || (major == min_major && minor >= min_minor);
+#endif
 }
 
 #endif /* __KSELFTEST_H */
diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c
index d86a0e00711e..878496d2a656 100644
--- a/tools/testing/selftests/timers/posix_timers.c
+++ b/tools/testing/selftests/timers/posix_timers.c
@@ -241,7 +241,7 @@ static int check_timer_distribution(void)
 
 	if (!ctd_failed)
 		ksft_test_result_pass("check signal distribution\n");
-	else if (ksft_min_kernel_version(6, 3))
+	else if (ksft_min_kernel_version(6, 3) > 0)
 		ksft_test_result_fail("check signal distribution\n");
 	else
 		ksft_test_result_skip("check signal distribution (old kernel)\n");
-- 
2.25.1.362.g51ebf55