Bug 1191122 – ntpd -x steps clock on leap second

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Bug 1191122 - ntpd -x steps clock on leap second

Summary:	ntpd -x steps clock on leap second

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	ntp (Show other bugs)
Sub Component:
Version:	7.1
Hardware:	All Linux

Priority	urgent Severity high
Target Milestone:	rc
Target Release:	---
Assigned To:	Miroslav Lichvar
QA Contact:	Jakub Prokes
Docs Contact:

URL:
Whiteboard:
Keywords:	ZStream

Depends On:
Blocks:	1205796 1110700 1133060 1191021 1214752
	Show dependency tree / graph

Reported:	2015-02-10 08:47 EST by Miroslav Lichvar
Modified:	2015-11-19 03:38 EST (History)
CC List:	15 users (show)

See Also:
Fixed In Version:	ntp-4.2.6p5-20.el7
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:	1190619
Clones:	1214752 (view as bug list)
Environment:
Last Closed:	2015-11-19 03:38:15 EST
Type:	Bug
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Network Time Protocol	2745	None	None	None	Never
Red Hat Product Errata	RHSA-2015:2231	normal	SHIPPED_LIVE	Moderate: ntp security, bug fix, and enhancement update	2015-11-19 04:03:04 EST

Groups: None (edit)

Description Miroslav Lichvar 2015-02-10 08:47:08 EST

+++ This bug was initially created as a clone of Bug #1190619 +++

Description of problem:
With older ntp versions, the -x option was sometimes used as a workaround to avoid kernel inserting/deleting leap seconds by stepping the clock and possibly upsetting running applications. That no longer works with 4.2.6 as ntpd steps the clock itself when a leap second occurs.

The fix is to treat the one second offset gained during leap second as a normal offset and check the stepping threshold (set by -x or tinker step) to decide if a step should be applied.

Version-Release number of selected component (if applicable):
ntp-4.2.6p5

How reproducible:
Always

Steps to Reproduce:
1. add -x to /etc/sysconfig/ntpd
2. wait for leap second
3. observe how was clock corrected

Actual results:
step

Expected results:
slew

Comment 18 errata-xmlrpc 2015-11-19 03:38:15 EST

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHSA-2015-2231.html

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