[ntp:questions] Leap second indication (Linux NTPD specifically)

Phil Fisher Phil.Fisher at ipaccess.com
Tue Mar 6 10:28:21 UTC 2012

Hi folks
I have spent some time recently looking through the results of various G***le searches relating to LI and Leap Second and other related matters and cannot find an answer to the below.
I would appreciate help since we need to cover the scenario where our 2.6.9 Linux kernel may crash/hang when a leap Second insert occurs (due to the printk bug).

Some context to avoid repetitive simple answers along lines of upgrade XYZ:
* we cannot move to the later 2.6.29 kernel for commercial reasons
* we have an old NTP implementation: ntpd: ntpd 4.2.0a at 1.1190-r Mon Oct 11 09:10:20 EDT 2004 (1)
and again we cannot upgrade this -- certainly in the timeframe prior to June 2012.

In view of the above, my question(s) are:

+ is there a way to disable the kernel from implementing the leap second from a prior announcement? (I.e. during June the NTPD receives a LI notification and tells kernel -- my reading of various posts and RFC/protocol suggests that this can occur anytime in June and specifically in the 24 hours prior to leap second implementation)
+ will stopping NTPD temporarily for a few days around the end of June avoid having the leap second implemented? (Re-enabling NTPD post the 30 June should re-synchronise time after some interval, correct?)
These two questions are related to a potential strategy for covering the leap second hiatus.


Phil Fisher| BSC Platform Engineer (Linux)
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