Subject: Re: 1.6_BETA3 /cats crashing
To: None <david@flossy.u-net.com>
From: Chris Gilbert <chris@paradox.demon.co.uk>
List: port-cats
Date: 07/09/2002 22:42:10
On Tue, 2002-07-09 at 23:21, david@flossy.u-net.com wrote:
> > Certainly I'm starting to look at the cats irq handling, and have been
> > trying to think of how to do generic soft interrupts (other archs have
> > <32 interrupt bits, we've actually got a full 32 interrupts on
> > footbridge)
> > 
> > I might try rigging up my USB speakers and do disk stuff see if I can
> > provoke a crash.
> 
> Any luck with this?

Sadly not had time...

> I've tried two things, without much luck, and discovered another issue:
> 
> 1) Downloading latest BETA4 source.  No change.
> 2) Enabling PMAPDEBUG to see if that sheds any light on anything... however, dropping into the DDB appears to disable the console kbd after continuing.
> Not even caps lock responds :-(

Hmm, not seen that, will check...


> 
> In general terms is this bug likely to be:
> 
> a) failing to reset intr_depth when leaving an interrupt routine, and next data abort bombs?
> b) page fault occurs in interrupt code.  Is this possible?  Any thoughts on likely reasons?

> This might be advertising how little I know about the kernel, but I'm just trying to isolate the fault and then see if I can find
> what's changed between 1.5.2 and .16

I'd say it's b.  a page fault occurs when the system attempts to access
code not in memory, in the kernel nothing should access something not
already in memory.

Note I'm tired so may not be making snese...

Chris