Comment # 9 on bug 917411 from Takashi Iwai

(In reply to macias - from comment #8)
> > > I wrote "freeze", not "crash" -- those are 2 different things.
> >
> > Then you have to write more clearly.  
> 
> Please give me an example, because obviously "freeze" for denoting "freeze"
> was not clear enough.

What's needed is what kind of freeze you got.  For example, if the machine
doesn't respond to network ping, it's likely a complete freeze.  Meanwhile,
often a desktop problem is just a graphics freeze, and the remote login still
works.  Or, at least, if ping returns, it implies that the kernel still alives
but the desktop environment is frozen by some reasons.

In the case of complete freeze, usually it's a kernel panic, and the kernel
always tries to leave some dying messages.  If you have luck, it'll be recorded
and left intact in the kernel messages on disk.  If you have no lock, you'll
have to catch the message remotely, at best via a serial console, or via
netconsole, etc.

If you have no such capability, at least, try to enable the magic sysrq in
sysctl (via /usr/lib/sysctl.d/*).  Set kernel.sysrq=1 will enable the all sysrq
controls.  Then, at freeze, give alt-sysrq-s to sync, alt-sysrq-t to get the
stack trace of all running tasks.  Also, you can try alt-sysrq-k, alt-sysrq-u,
and finally alt-sysrq-b to reboot.  This might leave something better on disk,
again, if you have luck.

> I am closing this report, I don't know how to perform the task you ask for,
> besides after 3 freezes I am not risking another one.

OK, feel free to reopen if you face the same problem and have some more
information.