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

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

[devzero]

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

[Roger Heflin]

devzero@web.de wrote:
> 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
> 
> 

This is real hardware, it is a always on desktop MB machine, nothing too weird, 
right now I am putting 2.6.24.4 on it, and we will see in a few weeks if it does 
it again.

I am getting it fairly consistently, so any ideas of what to turn on, or watch 
for in the next event would be useful.    I did try collect several samples of 
information from /proc of things that looked useful, the most telling thing I 
found was that it appeared that in /proc/timer_list

now at 7300171087468 nsecs (number was different).

was actually looping similar to the time/date and not rising as it should have 
been, this is a 32 bit on an AMD Sempron(tm) Processor 3400+, it is 64bit 
capable. I did have files that containing several samples of /proc/timer_list, 
but apparently the alt-sysrq-s then u before the b failed to save the 
information or the general state of the machine was just so bad that it did not 
get written out to disk, the last 2 times I have had this happen, it completely 
failed to shutdown gracefully and s-u-b at least enabled me to force a reboot 
without having to go to the machine and power cycle it.

 From previous data, the shortest time is 14 days 11 hours, and the longest is 
about 23 days.


                                Roger