[gentoo-user] spontaneous reboots.. what to look for

[Harry Putnam <reader@newsguy.com>]

I've been experiencing spontaneous reboots on one gentoo machine
lately.  Looking thru /var/log/messages... I see the restarts but
looking above that... I'm not seeing anything I recognize as being a
culprit. 

Its been happening for a few weeks... but I've been busy and only now
digging into it ( The machine is no kind of server ).

It appears to only happen in X (I'm using xfce4) and I've only noticed
it since I started running 2.6.28 kernels.  Although I couldn't say
that it seemed to be directly related.

I mean I didn't boot into 2.6.28 and suddenly notice spontaneous
rebooting. 

It does not appear to be heat realated... but I am only now using
lm_sensors to keep an accurate record and see if there appears to be a
relationship. 

I've had two today so either its happening more often or I'm just
spending more time on that machine.

It may also be on the first or second time its happened while I as
actually right at the keyboard.

I'm sorry to be so vague about it, but in truth, I've been pretty lazy
about it... since no real harm comes of an unexpected reboot on that
machine (so far anyway).  But clearly something that has to be figured
out. 

The only things I've checked so far... 
1) browsing thru /var/log/messages (Having trouble recognizing any
   thing that looks suspicious.

   I have noticed what appears to be a time/date anomaly where the
   progression of time is suddenly irregular.  That is, an earlier
   time shows up amongst some later times.

   It appears to have been me sudoing to visudo.  And apparently
   having /etc/sudoers open long enough for the closing of it to be
   earlier than other events taking place.
   
   Again ... I'm not real sure exactly what happened there but it
   does not appear to coincide with a reboot anyway.
 
2) checking how hot the cpu is getting (Doesn't appear to be a
   problem) But now running a cron job recording temperatures every 10
   minutes. So that may turn up something.

3) checking for overfilled disks.  (none show in df -h)