Re: Realtime Preemption, 2.6.12, Beginners Guide?

From: Alistair John Strachan
Date: Fri Jul 08 2005 - 16:13:48 EST


On Friday 08 Jul 2005 20:48, Ingo Molnar wrote:
> * Alistair John Strachan <s0348365@xxxxxxxxxxxx> wrote:
> > Unfortunately I see nothing like this when the machine crashes. Find
> > attached my config, which has CONFIG_4KSTACKS and the options you
> > specified. Are you sure this is sufficient to enable it?
>
> i have booted your .config, and stack overflow debugging is active and
> working. So it probably wasnt a straight (detectable) stack recursion /
> stack footprint issue.
>

Okay, I disabled IO-APIC and Local APIC, recompiled with (an otherwise
identical) config.

Got this (slightly better) oops. Figured out how to use my camera :-)

http://devzero.co.uk/~alistair/oops6.jpeg

Onto your stack-footprint metric. I don't know what the number means, but at a
guess it's the size of the stack. Unfortunately, if this is the case, it's
unlikely to be an overflow causing the crash. Here's a grep of dmesg just
before the crash.

[root] 21:39 [~] dmesg | grep new\ stack
| new stack-footprint maximum: swapper/1, 1760 bytes.
| new stack-footprint maximum: mount/471, 1716 bytes.
| new stack-footprint maximum: cupsd/2623, 1564 bytes.
| new stack-footprint maximum: kdm_greet/2845, 1528 bytes.
| new stack-footprint maximum: krootimage/2846, 1204 bytes.
| new stack-footprint maximum: konqueror/2938, 836 bytes.

The complete traces are a bit long to include here, but I've uploaded the
entire dmesg:

http://devzero.co.uk/~alistair/dmesg.gz

--
Cheers,
Alistair.

personal: alistair()devzero!co!uk
university: s0348365()sms!ed!ac!uk
student: CS/CSim Undergraduate
contact: 1F2 55 South Clerk Street,
Edinburgh. EH8 9PP.
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