Re: Debugging mysterious freeze / crash

[Celejar <celejar@gmail.com>]

On Mon, 24 Sep 2018 17:17:28 +0300
Selim T. Erdoğan <selim@alumni.cs.utexas.edu> wrote:

> On Sat, Sep 22, 2018 at 10:51:27PM -0400, Celejar wrote:
> > 
> > I've been experiencing a great deal of frustration recently with
> > intermittent freezes / crashes on my Debian Sid system (a Lenovo
> > W550s). The symptoms are that the screen totally freezes and the system
> > becomes completely unresponsive (even ssh attempts from another machine
> > fail), and the only thing that seems to have any effect is a hard
> > reboot (holding down the power button until the system restarts).
> > 
> > Upon reboot, I can't find anything at all interesting in 'journalctl -b
> > -1', or /var/log/syslog - the former just shows everything looking
> > normal until the moment of the crash, at which point the log just ends,
> > and the latter also just shows everything seeming to be fine until the
> > moment of the crash, and then shows the boot messages from the reboot.
> > 
> > Any ideas of what could be causing this, or how I could go about
> > debugging it? I've been using this machine for years without
> > experiencing anything like this, and I'm not sure for how long this has
> > been a problem. I did recently upgrade from stable to unstable, but I'm
> > not sure whether or not the problem's initial occurences coincide with
> > the upgrade.
> 
> 
> How long have you waited before you reboot?  I occasionally (pretty 
> rarely, thankfully) get freezes on my Lenovo T400 running Debian 9
> Stretch (stable) and I used to think I would have to hard reboot it 
> like you do, but I noticed that they actually get fixed if I wait up to 
> a few minutes.  Never timed them but the longest probably lasted more 
> than five minutes.  Usually they're less than a minute.  

I don't usually (if ever) wait that long. If it happens again, I'll try
to wait it out a bit longer and see what happens.

> When these freezes happen, it seems it is relatively soon after starting 
> to use the laptop after it's been suspended overnight or so.  They're 
> rare, though.  I didn't try ssh'ing at the time but everything is 
> completely frozen.  And finally, these freezes didn't use to happen a 
> year ago or earlier but it's been at least a few months that this has 
> been going on.
> 
> Your machine and Debian version seem much newer but I thought I'd share 
> my experience.

Thanks - I just wish I understood what the problem is, how to
diagnose it properly, and even more importantly, how to fix it.

Celejar