[ntp:questions] Leap second bug?

David L. Mills mills at udel.edu
Fri Jan 4 15:18:36 UTC 2008


Spoon wrote:

> Spoon wrote:
> 
>> ntpd kicked my clock forward one second on January 1 at 00:19:38 UTC.
>>
>> (My ntp.conf lists 12 servers. Delays range from 28 to 48 ms.)
>>
>> Dec 31 23:25:39 offset 0.000329 sec freq -6.715 ppm error 0.000333 poll 8
>> Dec 31 23:28:39 offset 0.000329 sec freq -6.715 ppm error 0.000340 poll 8
>> Dec 31 23:31:39 offset 0.000329 sec freq -6.715 ppm error 0.000424 poll 8
>> Dec 31 23:34:39 offset 0.000403 sec freq -6.714 ppm error 0.000493 poll 8
>> Dec 31 23:37:39 offset 0.000270 sec freq -6.714 ppm error 0.000348 poll 8
>> Dec 31 23:40:39 offset 0.000270 sec freq -6.714 ppm error 0.000337 poll 8
>> Dec 31 23:43:39 offset 0.000268 sec freq -6.714 ppm error 0.000327 poll 8
>> Dec 31 23:46:39 offset 0.000268 sec freq -6.714 ppm error 0.000381 poll 8
>> Dec 31 23:49:39 offset 0.000268 sec freq -6.714 ppm error 0.000446 poll 8
>> Dec 31 23:52:39 offset 0.000268 sec freq -6.714 ppm error 0.000446 poll 8
>> Dec 31 23:55:39 offset 0.000268 sec freq -6.714 ppm error 0.000334 poll 8
>> Dec 31 23:58:39 offset 0.000268 sec freq -6.714 ppm error 0.000317 poll 8
>> Jan  1 00:01:38 offset 0.000268 sec freq -6.714 ppm error 0.000318 poll 8
>> Jan  1 00:04:38 offset 0.000268 sec freq -6.714 ppm error 0.447285 poll 8
>> Jan  1 00:06:47 synchronized to A, stratum 2
>> Jan  1 00:07:38 offset -0.001068 sec freq -6.720 ppm error 0.632509 
>> poll 8
>> Jan  1 00:10:38 offset -0.001068 sec freq -6.720 ppm error 0.632509 
>> poll 8
>> Jan  1 00:13:38 offset -0.001068 sec freq -6.720 ppm error 0.774695 
>> poll 8
>> Jan  1 00:15:39 synchronized to H, stratum 1
>> Jan  1 00:16:38 offset -0.001068 sec freq -6.720 ppm error 0.632382 
>> poll 8
>> +++++
>> Jan  1 00:19:38 time reset +0.999402 s
>> +++++
>> Jan  1 00:19:38 system event 'event_clock_reset' (0x05) status 
>> 'sync_alarm, sync_unspec, 15 events, event_peer/strat_chg' (0xc0f4)
>> Jan  1 00:19:38 system event 'event_peer/strat_chg' (0x04) status 
>> 'sync_alarm, sync_unspec, 15 events, event_clock_reset' (0xc0f5)
>> Jan  1 00:19:39 offset 0.000000 sec freq -6.720 ppm error 0.447203 poll 4
>> Jan  1 00:19:54 peer A event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:19:55 peer B event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:19:59 peer C event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:20:04 peer D event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:20:07 peer E event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:20:08 peer F event 'event_reach' (0x84) status 'unreach, 
>> conf, 4 events, event_reach' (0x8044)
>> Jan  1 00:20:14 peer G event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:20:18 peer H event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:20:24 peer I event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:20:26 peer J event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:20:28 peer K event 'event_reach' (0x84) status 'unreach, 
>> conf, 2 events, event_reach' (0x8024)
>> Jan  1 00:20:39 peer L event 'event_reach' (0x84) status 'unreach, 
>> conf, 4 events, event_reach' (0x8044)
>> Jan  1 00:20:55 synchronized to A, stratum 2
>> Jan  1 00:20:55 system event 'event_sync_chg' (0x03) status 
>> 'leap_none, sync_ntp, 15 events, event_peer/strat_chg' (0x6f4)
>> Jan  1 00:20:55 system event 'event_peer/strat_chg' (0x04) status 
>> 'leap_none, sync_ntp, 15 events, event_sync_chg' (0x6f3)
>> Jan  1 00:21:22 synchronized to H, stratum 1
>>
>> I also noticed that, the day before, the STA_INS (insert leap second) had
>> been set and reset several times.
>>
>> Dec 31 00:14:30 kernel time sync status change 0011
>> Dec 31 00:27:21 kernel time sync status change 0001
>> Dec 31 03:19:46 kernel time sync status change 0011
>> Dec 31 03:52:30 kernel time sync status change 0001
>> Dec 31 04:09:33 kernel time sync status change 0011
>> Dec 31 04:35:11 kernel time sync status change 0001
>> Dec 31 07:26:03 kernel time sync status change 0011
>> Dec 31 07:47:28 kernel time sync status change 0001
>> Dec 31 10:00:51 kernel time sync status change 0011
>> Dec 31 10:17:01 kernel time sync status change 0001
>>
>> (Apparently, the bit was not set when 2007 ended.)
>>
>> Could this be a leap year bug? or did I just lose connectivity at the 
>> wrong
>> time and it's just a coincidence?
>>
>> # ntpq -crv
>> assID=0 status=06f4 leap_none, sync_ntp, 15 events, event_peer/strat_chg,
>> version="ntpd 4.2.4p0 at 1.1472 Fri Mar 16 10:45:43 UTC 2007 (1)",
>> processor="i686", system="Linux/2.6.22.1-rt9", leap=00, stratum=3,
>> precision=-20, rootdelay=30.293, rootdispersion=50.341, peer=39672,
>> refid=145.238.203.10,
>> reftime=cb262893.e5d244fd  Wed, Jan  2 2008 15:13:23.897, poll=8,
>> clock=cb262c3b.dbe5d3de  Wed, Jan  2 2008 15:28:59.858, state=4,
>> offset=0.081, frequency=-6.758, jitter=0.525, noise=0.521,
>> stability=0.001
> 
> 
> Would someone care to venture their best guess as to what caused ntpd
> to step the system clock forward in the above scenario?
> 
> Regards.




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