Re: root NFS causes solid lockup, serial console no help, watchdog NMI won't function on Dual AMD system

[Brad Barnett <lists@l8r.net>]

On Mon, 13 Nov 2006 16:45:07 -0500
Brad Barnett <lists@l8r.net> wrote:

> 
> 
> Hello,
> 
> I have a couple of dual AMD Opteron system with differing motherboards. 
> On both of these differing pieces of hardware, I can not enable the NMI
> watchdog timer, with nmi_watchdog=1.  I constantly get:
> 
> testing NMI watchdog ... CPU#0: NMI appears to be stuck (0->0)!
> 
> This happens when booting with both Debian's packaged kernels, 2.6.17-2
> and 2.6.18-2.  According to this page:
> 
> http://www.mjmwired.net/kernel/Documentation/nmi_watchdog.txt
> 
> nmi_watchdog=2 does not work with AMD systems at this time.
> 
> Both boxes, aside from this, boot fine.  They use nfsroot, booting the
> kernel off of a local drive, and switching to nfsroot during the bootup.
> 
> They work flawlessly for anywhere from a week to a few days, then lock
> up solid.  I can not seem to reproduce this problem unless I am using
> nfsroot, and the above kernels seem fine without issue when booting and
> running off of a local drive.
> 
> I can not get any information from a serial console, and just for fun I
> redirected syslog to another box, yet I did not see anything about the
> impending doom to come.  The console itself is simply a blank screen,
> and the keyboard is dead... 
> 
> Does anyone have any suggestions for tracking this bug down?
> 
> Thanks
> 


An update.

I just had a reoccurrence of this bug, without using NFS root.  This is
under Debian's packaged 2.6.17-2, and the same issue occurred with
2.6.18-2.  Total and complete system lockup.  Serial console is fruitless.

I have been forced to downgrade to 2.6.9.  Does anyone out there, have any
ideas for debugging this complete lockup in 2.6.17/2.6.18?  It seems to be
NFS activity related, but I can not verify this at this point in time.