Re: Realtime Preemption, 2.6.12, Beginners Guide?

[Ingo Molnar]

* Alistair John Strachan <s0348365@xxxxxxxxxxxx> wrote:

> > do you have DEBUG_STACKOVERFLOW and latency tracing still enabled?  The
> > combination of those two options is pretty good at detecting stack
> > overflows. Also, you might want to enable CONFIG_4KSTACKS, that too
> > disturbs the stack layout enough so that the error message may make it
> > to the console.
> 
> I already have 4KSTACKS on. Latency tracing is enabled, but 
> STACKOVERFLOW isn't; I'll just reenable everything again until we fix 
> this. Do you think if I removed the printk() line I might get some 
> useful information, before it does the stack trace?

usually such loops happen if the stack has been overflown and critical 
information that lies on the bottom of the stack (struct thread_info) is 
overwritten. Then we often cannot even perform simple printks. Stack 
overflow debugging wont prevent the crash, but might give a better 
traceback.

	Ingo
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