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 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 --- tools/testing/selftests/timers/raw_skew.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/timers/raw_skew.c b/tools/testing/selftests/timers/raw_skew.c index ca6cd14..d3fc453 100644 --- a/tools/testing/selftests/timers/raw_skew.c +++ b/tools/testing/selftests/timers/raw_skew.c @@ -94,6 +94,7 @@ int main(int argv, char **argc) struct timespec mon, raw, start, end; long long delta1, delta2, interval, eppm, ppm; struct timex tx1, tx2; + int adj_offset_bad = 0;

setbuf(stdout, NULL);

@@ -108,8 +109,10 @@ int main(int argv, char **argc) start = mon; delta1 = diff_timespec(mon, raw);

- if (tx1.offset) + if (tx1.offset) { printf("WARNING: ADJ_OFFSET in progress, this will cause inaccurate results\n"); + adj_offset_bad = 1; + }

printf("Estimating clock drift: "); sleep(120); @@ -134,6 +137,10 @@ int main(int argv, char **argc) printf(" %lld.%i(act)", ppm/1000, abs((int)(ppm%1000)));

if (llabs(eppm - ppm) > 1000) { + if (adj_offset_bad) { + printf(" [SKIP]\n"); + return ksft_exit_skip("ADJ_OFFSET in progress. Shutdown NTPd or other time steering daemons\n"); + } printf(" [FAILED]\n"); return ksft_exit_fail(); }