Mysterious hangs

Doug White dwhite at
Fri Apr 15 10:18:17 PDT 2005

On Wed, 13 Apr 2005, Eirik [ISO-8859-1] Øverby wrote:

> Sorry, this was meant for the amd64 list.
> Got another report for this list. Confused the addresses.
> On 13-04-05 07:28, "Eirik Øverby" <ltning at> wrote:
> > Hi,
> >
> > For some time I've been seeing infrequent and seemingly random hangs on my
> > dual opteron system. Motherboard is Tyan K8S Pro. Until now I thought it was a
> > "hard" hang, but I've got serial console hooked up and BREAK_TO_DEBUGGER, DDB
> > and KDB in the kernel, and when sending a break through telnet I get:
> >
> > telnet> send brk
> > KDB: enter: Line break on console

I have a rev-D HDAMA that hangs like this. If you set
debug.kdb.stop_cpus=0 then ddb will enter, which leads me to believe one
of the CPUs is going out to lunch.

I had a rev-G HDAMA that upgrading the BIOS fixed this on, so you might
try that.  I can only assume the BIOS difference includes a tweak to a
timing somewhere; I've been wanting to mess with the HyperTransport clocks
but haven't had time, but HT problems would likely cause wierdcCPU
communication issues.

I have an S2881 that does not exhibit the problem.

> > And nothing more. Which means the box is sort of alive, but fails to present
> > even the kernel debugger. The machine is currently on 5.4 as of yesterday.
> > It's been hanging before (with anything from days to weeks between), under
> > various variations of 5.x, but I haven't had the serial console before now.
> >
> > Has any one seen this before? Any ideas what I could look at? I suspected
> > hardware, but it seems that isn't the case as most HW errors I've seen would
> > cause a total freeze.
> >
> > Here's to hoping.
> >
> > Thanks,
> > /Eirik
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Doug White                    |  FreeBSD: The Power to Serve
dwhite at          |

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