From owner-freebsd-smp  Mon Jun 10  8:58:35 2002
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Date: Mon, 10 Jun 2002 08:59:33 -0700
From: Arun Sharma <arun@sharma-home.net>
To: dnu <dnu@info.com.ph>
Cc: freebsd-smp@freebsd.org
Subject: Re: Page faults in kernel mode
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On Mon, Jun 10, 2002 at 03:59:38PM +0800, dnu wrote:
> Hello Arun,
> 
> Does this happen in uniprocessor mode?
> What motherboard are you using?  Did you use ecc ram?
> 
> David

David,

I haven't had a chance to try it in UP mode. For that I need to compile
a kernel and my (only FreeBSD) box isn't stable enough to permit that.

The motherboard I'm using is Abit BP6 with two celerons (it was popular
back in 99). I'm running non-ecc RAM.

While I try to reproduce it with a UP kernel and more reliable RAM, I
have some indications on where some of these are coming from:

I have a suspicion that in kern_mutex.c:510, 

                        if (td1->td_priority < td->td_priority)

there may be circumstances in which td1 could be pointing to memory that
has been freed. I've got a bunch of panics which result in kernel mode
page faults at 0xdeadxxxx.

	-Arun
> 
> 
> >Running on a dual celeron box.
> >
> >CPU: Pentium II/Pentium II Xeon/Celeron (367.50-MHz 686-class CPU)
> >  Origin = "GenuineIntel"  Id = 0x665  Stepping = 5
> >  
> >Features=0x183fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,C>
> >real memory  = 201326592 (196608K bytes)
> >avail memory = 191365120 (186880K bytes)
> >
> >FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
> > cpu0 (BSP): apic id:  0, version: 0x00040011, at 0xfee00000
> > cpu1 (AP):  apic id:  1, version: 0x00040011, at 0xfee00000
> > io0 (APIC): apic id:  2, version: 0x00170011, at 0xfec00000

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