Kubuntu System Hangs!

[Matthias Heiler]

Kenneth Jacker <khj at be.cs.appstate.edu> writes:

>   >> PROBLEM:  my system occasionally "hangs"
> 
>   mh> I experienced similar problems (seemingly random hard freezes) with
>   mh> kubuntu-5.04 and relatively new Dell hardware.
> 
> Mine is a Dell as well ... bought it, maybe, 3-4 years ago. 
> Similar in age to yours?

Mine was bought last year.  It contained a new chip set and the linux
support was buggy at that time.

>   mh> It turned out that the kernel did not properly support the SATA
>   mh> drives at that time.
> 
> That might be it.  However, why would it have worked fine with
> Debian/sarge?  Can't remember exactly which SMP kernel, but it was
> definitely later in the 2.6.x series ...
> 
> Does Ubuntu/Kubuntu maintain their own kernels or just use those
> from Debian?

I believe so.  For instance, ubuntu kernels support intel's wireless
directly (although the wireless driver hangs now and again), while the
last time I checked you had to recompile the Debian kernel to achieve
the same.

>   mh> The fix was to use some suitable kernel parameters (namely,
>   mh> "pci=bios idle=halt") ...
> 
> Could you translate those?  Maybe I should try booting with them?

They probably won't do any harm at least.  You can check them and many
others by looking for the file "kernel-parameters.txt" in your
kernel's source code tree.

The problem is that unless you find a way to reproduce the freeze it's
extremely slow and frustrating to find the correct kernel parameters
by trial and error.

>   mh> .. and to use always the latest kernel (2.6.12 works perfect for me).
> 
> As I mentioned already, I was using the 2.6.12-10-686-smp kernel.  I'd
> guess that's pretty much up-to-date, no?

Sounds so.  Probably your problem is different from what I had.

> So, I came in to my office last night and rebooted with the non-SMP
> kernel (2.6.12-10-686).  We'll see if that makes any difference ...

As a general rule, if you don't have multiple CPUs/ hyperthreading/
multicore running you have no benefit from the SMP kernel.

> Thanks, Matthias, for your ideas.  Anyone else know how I can
> determine just what is causing this (very undesirable) behavior?

Another thing you can do is do a memory check.  Maybe some RAM is
broken.  There should be an entry in the boot menu.

Other ideas: Does the freeze occur when you do a lot of IO?  IO to
disk? IO to the network?  Does heavy graphics output trigger the
freeze?  And so on.

Finally, I'm using the kubuntu distribution for a year now, and I'm
not 100% happy with it.  The kubuntu community seems to favor using
the most recent software versions over simplicity, stability, and
reliability.  (Take the switch to the currently still buggy gstreamer
sound system in 5.10 as an example.)  Although I'm not a fan of Gnome
it might be worth a try to run the machine under Gnome for a while and
look if it continues to freeze.

Yours,

  Matthias

PS: If you find a fix for the problem, it would be nice to hear about it.