Re: Clock has stopped (time/date looping over 5 seconds), things are

From: devzero
Date: Fri Apr 04 2008 - 20:51:18 EST


so, this happens on real hardware for you?

i could reproduce this with a linux virtual machine on vmware - whenever i suspended the windows host with a linux vm running in vmware, after resume the linux vm showed exactly this issue.
after some investigation i found, that it would recover from that state after some time - and the time needed for recover was (more or less) proportional to that time the host was in suspend(hibernate) state.

also see http://marc.info/?l=linux-kernel&m=120186717701371&w=2

i thought that was vmware related and i gave a bug report to dan hecht - i didn`t hear anything since then, but i think it`s worth CC`ing him.

not sure if
[PATCH 1/2] Introduce clocksource_forward_now -> http://marc.info/?l=linux-kernel&m=120716471203567&w=2
[PATCH 2/2] Introduce CLOCK_MONOTONIC_RAW -> http://marc.info/?l=linux-kernel&m=120596518521892&w=2
is related ? (also CC`d the patch authors, they will probably know)

regards
roland



List: linux-kernel
Subject: Clock has stopped (time/date looping over 5 seconds), things are
From: Roger Heflin <rogerheflin () gmail ! com>
Date: 2008-04-04 21:27:11
Message-ID: 47F69D2F.8010607 () gmail ! com
[Download message RAW]

So far what I have is that the clock is moving between
10:01:03 to 10:01:07 (when it gets to 07 it goes back to 03), doing rdate -s
results in things changing:

16:12:38 to 16:12:43 (resets back to :38).

Doing this:
while true ; do date; usleep 1000000; done
Fri Apr 4 16:12:39 CDT 2008
Fri Apr 4 16:12:40 CDT 2008
Fri Apr 4 16:12:41 CDT 2008
Fri Apr 4 16:12:42 CDT 2008
Fri Apr 4 16:12:43 CDT 2008

It stops at :43, ^C is required, and you can then restart it with repeatable
results.

This F7 - 2.6.23.15-80.fc7

dmesg/messages contain nothing abnormal.

This machine has done it several times, a freqency of maybe 1x per every couple
of weeks or so. I believe it had also done this with: 2.6.22.9-91.fc7 so it
has been doing this for a while. It used to work with some older kernel (I
don't know which).

Given what the clock is doing, things that sleep at the wrong time hang forever,
and a number of other things fail to work.

vmstat 1 results in a single line being printed out, and then a floating point
exception.

"shutdown -r now" fails to complete, power cycle is required to get the machine
back up.

I don't believe any hardware failure that I can think of would cause the clock
to do what mine is doing.

Ideas?

Roger
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