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

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

[Dale]

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

:-)  :-)

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

[Nikos Chantziaras]

On 06/13/2011 12:18 PM, Dale wrote:
> So, my question is this. What kind of lock up could keep the magic keys
> from working?

When the part of the kernel that handles sysrq also locked up :-P

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

[meino.cramer]

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

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

[JDM]

I used to get this when using ati-drivers (radeon). This has not happened for a good year though. Sysreq not responsive but you could ssh into machine. Ssh maybe worth a try. If you do not have radeon then the advise is close to meaningless. 
JDM

-----Original Message-----
From: Dale <rdalek1967@gmail.com>
Date: Mon, 13 Jun 2011 04:18:23 
To: Gentoo User<gentoo-user@lists.gentoo.org>
Reply-to: gentoo-user@lists.gentoo.org
Subject: [gentoo-user] Questions about the magic Sys Req keys

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

:-)  :-)

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

[Volker Armin Hemmann]

On Monday 13 June 2011 04:18:23 Dale wrote:

> So, my question is this.  What kind of lock up could keep the magic keys
> from working?  This is on my new amd64 machine.  

everything that kills the interrupt handler.

everything that prevents the kernel from acting on interrupts it received

everything that locks up the CPU

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

[Dale]

Volker Armin Hemmann wrote:
> On Monday 13 June 2011 04:18:23 Dale wrote:
>
>    
>> So, my question is this.  What kind of lock up could keep the magic keys
>> from working?  This is on my new amd64 machine.
>>      
> everything that kills the interrupt handler.
>
> everything that prevents the kernel from acting on interrupts it received
>
> everything that locks up the CPU
>
>    

Thanks for all the replies.  It appears I am on the right track.  I most 
likely have a bad kernel.  It's been a while since I had one of those.  
I guess one has to get through every once in a while.

Oh, I have a nvidia card.

Thanks

Dale

:-)  :-)