What is this panic?

[Gene Spafford]

We've just recently brought up 4.2 BSD on 3 750 Vaxen.  Each Vax is
configured with 2 or 3Mbyte memory, Rev 7 CPU boards, DEUNA ethernet
drivers, a DZ-32 board, an RL02 disk, and a UDA50 disk controller
running 1, 2, or 3 RA81 disks.

All three machines keep dying with a (claimed) tbuf parity problem.
However, the value in the mcesr register indicates a bus error rather
than a tbuf error.  The PC of the last few faults was in some of the
UDA50 code (udrsp) or the hardclock routine, while others were in user
address space; this seems to rule out any likely direct correspondance
with any particular software module.

The problem appears whenever the machines are under load, but there is
no sure way to bring on the problem.  Rebuilding 2 or 3 copies of Unix
at the same time seems to bring it on regularly, but not all the time.
This problem is rather annoying, to say the least, and I've had little
success either tracking the problem down or getting much co-operation
out of some of our local DEC people ("If it isn't a problem that occurs
with DEC software, it isn't our problem.").

Has anybody out there seen this before?  Anybody have a fix or
suggestion where I go from here?  If so, please drop me some mail (I
don't always have time to read my news in this group).  I'm enclosing
some samples of the error summary printed on the console (and log)
whenever the problem occurs.

Thanks in advance.
--gene


machine check 2: cp tbuf par fault
	va 12f90 errpc 6dfc mdr aaaaaaaa smr b rdtimo 0 tbgpar 0 cacherr 5
	buserr 6 mcesr 9 pc 6df0 psl 3c00004 mcsr 80016
panic: mchk
trap type 2, code = 0, pc = 80000d76
panic: Reserved operand

machine check 2: cp tbuf par fault
	va 7fffeb38 errpc 157d mdr 2d smr b rdtimo 0 tbgpar 0 cacherr 5
	buserr 6 mcesr 9 pc 157b psl 3c00004 mcsr 80016
panic: mchk
trap type 2, code = 0, pc = 80000d76
panic: Reserved operand

machine check 2: cp tbuf par fault
	va 7fffec6c errpc c5f8 mdr 0 smr b rdtimo 0 tbgpar 0 cacherr 4
	buserr 6 mcesr 9 pc c5f8 psl 3c00000 mcsr 80016
panic: mchk
trap type 2, code = 0, pc = 80000d76
panic: Reserved operand

machine check 2: cp tbuf par fault
	va 8017dfd4 errpc 8001c1f8 mdr 7c smr 8 rdtimo 0 tbgpar 0 cacherr 5
	buserr 6 mcesr 9 pc 8001c1f3 psl c00000 mcsr 80016
panic: mchk
trap type 2, code = 0, pc = 80000d76
panic: Reserved operand

machine check 2: cp tbuf par fault
	va 800336c4 errpc 800271fc mdr 0 smr 8 rdtimo 0 tbgpar 0 cacherr 4
	buserr 6 mcesr 9 pc 800271f9 psl 4150004 mcsr 80016
panic: mchk
trap type 2, code = 0, pc = 80000d76
panic: Reserved operand

machine check 2: cp tbuf par fault
	va 800336c4 errpc 800271fc mdr 0 smr 8 rdtimo 0 tbgpar 0 cacherr 5
	buserr 6 mcesr 8 pc 800271f9 psl 4150000 mcsr 80016
panic: mchk
trap type 2, code = 0, pc = 80000d76
panic: Reserved operand

machine check 2: cp tbuf par fault
	va 800336c4 errpc 800271fc mdr 0 smr 8 rdtimo 0 tbgpar 0 cacherr 4
	buserr 6 mcesr 8 pc 800271f9 psl 4150000 mcsr 80016
panic: mchk
trap type 2, code = 0, pc = 80000d76
panic: Reserved operand

machine check 2: cp tbuf par fault
	va 7ffff1a4 errpc 8000b188 mdr 7ffff184 smr 8 rdtimo 0 tbgpar 0 cacherr 5
	buserr 6 mcesr 9 pc 8000b186 psl c00000 mcsr 80016
panic: mchk
trap type 2, code = 0, pc = 80000d76
panic: Reserved operand
-- 
Off the Wall of Gene Spafford
The Clouds Project, School of ICS, Georgia Tech, Atlanta GA 30332
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