Problems with SMP on 6.1-STABLE-200608

[Don O'Neil]

I've been having problems with my server freezing up, having the #2 CPU
'shut down', kernel panics, and all sorts of nastyness....

Originally I thought it was exim, or possibly bind, or bad hardware (mb, cpu
or memory)... I've swapped out the motherboard & CPU's & memory from an old
server that was running 4.11 ROCK SOLID for years...

At first I thought the problem was solved, but now it's popping up again...
The 2nd CPU gets 'shut down', or kernel panics, esentially taking the system
offline.

If I install a single CPU (non-smp) kernel, then the system works fine... (I
did this on the old motherboard before I swapped it out, and it worked fine
too).. So I'm wondering if there is an SMP bug or problem I'm running into.

I'm running 6.1-STABLE-200608, an ISO image I downloaded from the archives
when I built the box (NOT 6.1-RELEASE). 

I'm runining an Intel Serverworks motherboard with 2 1.4 GHz PIII's... The
problem only seems to show up under high load.

I'm wondering what I should do here... 

I'm concerned about doing a binary upgrade to 6.2 won't fix the problem, and
I've tried using freebsd-update, but it complains about the version not
being compatible. 

If I do a binary upgrade from CD, will it also update the kernel sources so
I can build a new one? Will it complain about it not being compatible?

Is there a way to 'force' the ID of the system to be 6.1-RELEASE so that
freebsd-update will work? 

Will doing the 6.1-6.2 binary upgrade as posted by Colin also update the
kernel sources? 

Would my best option really be to start over with a fresh install rather
than upgrade? (this would be painful)

I'm going to try to test out 6.2 on the old MB/CPU combo to see if I can
re-create it under 6.2 as well before I do anything. As well as try doing an
upgrade on the bench from CD from 6.1-STABLE-200608 to 6.2-RELEASE... Since
this is a production server (and for months it was burned in with no
apparent issues) I only have 1 shot at this to do it right.

Any help/recomendation would be appreciated.