Re: [gentoo-user] Questions about the magic Sys Req keys

[meino.cramer@gmx.de]

Dale <rdalek1967@gmail.com> [11-06-13 11:24]:
> Howdy,
> 
> I just had a hard lock up.  I had a random reboot the other day while I 
> was sleeping as well.  This was with gentoo-sources 2.6.39.  I'm not 
> sure what caused the one the other day but I had several days of 
> uptime.  The one I just had was also after a few days of uptime.   I 
> was logged into KDE when EVERYTHING froze.  The mouse pointer wouldn't 
> move.  The clock stopped.  The numlock light wouldn't even change when 
> I hit the key for it.  So, X was locked up pretty good.  I also 
> couldn't switch to a console either.  This is the odd part.  I tried to 
> use the magic Alt SysReq keys to at least try to get a reasonable 
> shutdown.  They didn't work either.
> 
> So, my question is this.  What kind of lock up could keep the magic 
> keys from working?  This is on my new amd64 machine.  It was totally 
> stable until the kernel upgrade.  I think this could be a kernel issue. 
>  I booted a older kernel and will test it for a few days but wanted to 
> know what kind of lockups could keep the magic keys from working.  
> After the hal/xorg deal, we all know how I hate hard resets.  ;-)
> 
> Thanks much.
> 
> Dale
> 
> :-)  :-)
> 

Hi Dale,

this kind of locks happening - as far as I know - when the
kernel itsself hangs or crash (null pointer dereferences and such).

As long as the kernel does "something" (eats CPU cycles in a more
or less senseful way) the sysreq magic does work since it is due
to its nature located somewhere deep in the kernel just a little
bit above the surface of the hardware...:)

If the kernel crashes the lights may shine but there is no one
at home anymore.

Try to modularize as much as possible to seperate the good from
the bad and the ugly. 
May be upgradeing the kernel to 2.6.39.1 may help also.

Good luck!

Best regards,
mcc