In the past we've warned when ADJ_OFFSET was in progress, usually caused by ntpd or some other time adjusting daemon running in non steady sate, which can cause the skew calculations to be incorrect

Thus, this patch sets a flag which we check if the clock was being adjusted when we fail so that we don't cause false negatives.

Cc: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@kernel.org Cc: Miroslav Lichvar mlichvar@redhat.com Cc: Richard Cochran richardcochran@gmail.com Cc: Prarit Bhargava prarit@redhat.com Cc: Stephen Boyd sboyd@kernel.org Cc: Shuah Khan shuah@kernel.org Cc: linux-kselftest@vger.kernel.org Suggested-by: Miroslav Lichvar mlichvar@redhat.com Signed-off-by: John Stultz john.stultz@linaro.org --- v2: Widened the checks to look for other clock adjustments that could happen, as suggested by Miroslav --- tools/testing/selftests/timers/raw_skew.c | 5 +++++ 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/timers/raw_skew.c b/tools/testing/selftests/timers/raw_skew.c index ca6cd14..dcf73c5 100644 --- a/tools/testing/selftests/timers/raw_skew.c +++ b/tools/testing/selftests/timers/raw_skew.c @@ -134,6 +134,11 @@ int main(int argv, char **argc) printf(" %lld.%i(act)", ppm/1000, abs((int)(ppm%1000)));

if (llabs(eppm - ppm) > 1000) { + if (tx1.offset || tx2.offset || + tx1.freq != tx2.freq || tx1.tick != tx2.tick) { + printf(" [SKIP]\n"); + return ksft_exit_skip("The clock was adjusted externally. Shutdown NTPd or other time sync daemons\n"); + } printf(" [FAILED]\n"); return ksft_exit_fail(); }