[ntp:questions] Ruh, roh. Leap Second?

Martin Burnicki martin.burnicki at meinberg.de
Wed Jul 2 07:59:46 UTC 2008


David L. Mills wrote:
> Peter,
> I head the same comment over the jungle telegraph. However, in the
> distributions that leave here there is no such comment, so it would have
> to come from somewhere else or from a modified distribution. 

The message:

  Clock: inserting leap second 23:59:60 UTC

can be found in the Linux kernel sources. So this indicates ntpd has indeed
received a leap second announcement from an upstream time source and has
passed that announcement to the kernel which has then inserted the leap
second. AFAIK that's the way leap seconds should be handled on systems
which provide a kernel PLL.

The following "time reset" happened after that to undo the faulty leap
second and step back to the correct time. 

So the basic question is from which upstream time source the faulty leap
second announcement has been received. 

> To help 
> spot feckless fingers, recent versions have a protostats file in the
> statistics collection and "official" reports go there, as well as the
> system log if configured. These reports are described in the decode.html
> page in the docuentation.

I'm not familiar with the protostats file, but I assume it is only generated
if explicitely configured in ntp.conf, similar to the other stats files.

Since such faulty leap second announcements have been reported here several
times I'd really appreciate if there would be a log entry generated by
default if a leap second announcement is received. That log entry should
also indicate from which time source that announcement has been received,
so a faulty time source could easily be identified and fixed or discarded
in order to prevent those faults the next time.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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