CentOS
ntp package

ntpd seems to add offsets instead of subtracting them

Bug #1414925 reported by Thomas Schweikle
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
ntp (CentOS)
New
Unknown
ntp (Debian)
Fix Released
Undecided
Unassigned
ntp (Ubuntu)
Fix Released
Undecided
Unassigned

Bug Description

ntpd seems to add offsets instead of subtracting them from the running synchronized clock, leading to time running away fast in one direction -- forward if the offset is positive, -- backward if the offset is negative, until the offset reaches its maximum.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ntp 1:4.2.6.p5+dfsg-3ubuntu2.14.04.1
ProcVersionSignature: Ubuntu 3.13.0-44.73-generic 3.13.11-ckt12
Uname: Linux 3.13.0-44-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
Date: Tue Jan 27 08:25:55 2015
InstallationDate: Installed on 2014-02-10 (350 days ago)
InstallationMedia: Xubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016)
KernLog:

NtpStatus: ntpq: read: Connection refused
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: ntp
UpgradeStatus: Upgraded to trusty on 2014-02-18 (342 days ago)
modified.conffile..etc.ntp.conf: [modified]
mtime.conffile..etc.ntp.conf: 2015-01-27T07:41:51.747605

Revision history for this message
Thomas Schweikle (tps) wrote :
Revision history for this message
Thomas Schweikle (tps) wrote :

Seeing this behaviour on all distributions using ntp 4.2.6p5:

- Ubuntu 14.04
- CentOS 6.5
- Orcale Linux 6.5
- Debian 7

Bug seems resolved in ntp 4.2.8 as available from http://www.ntp.org

Revision history for this message
Thomas Schweikle (tps) wrote :

maybe it is a security problem if kerberos used: after a while your clock is of too much and you can't login any more.

Thomas Schweikle (tps)
no longer affects: ntp (CentOS)
Bug Watch Updater (bug-watch-updater)
Changed in ntp (CentOS):
status: Unknown → New
Robie Basak (racb)
Changed in ntp (Ubuntu):
assignee: nobody → Liam Young (gnuoy)
Revision history for this message
Liam Young (gnuoy) wrote :

Hi Thomas,
    I've tried to recreate this bug by having ntp correct a clock that is fast and also one that is slow and ntp seems to be working fine for me. I'll attach the output of the commands I tested with. Could you include the exact steps you went through please ?
Thanks
Liam

Changed in ntp (Ubuntu):
status: New → Incomplete
Christian Ehrhardt  (paelzer)
Changed in ntp (Debian):
status: New → Fix Released
Changed in ntp (Ubuntu):
status: Incomplete → Fix Released
Liam Young (gnuoy)
Changed in ntp (Ubuntu):
assignee: Liam Young (gnuoy) → nobody
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