Massive mysterious file system corruption on 4.2bsd

[David Melman]

I have encountered a most mysterious and serious problem
on our Unix4.2bsd on a Vax 750.

The symptom is the string "Login timed out afer 60 seconds"
is being written seemingly arbitrarily to files throughout
all file systems.  This includes binaries and DIRECTORIES.

I know this line comes from login.c if the user waits
more than a minute before finishing his password.

I have only one lead.
We have a DMZ-32 whose ports are connected to what we call a 
Terminal Consentrator (TC) which in turn is connect to a custom lan.
Mistakenly, a couple of ports on this TC were configured as terminal-ports
instead of host-ports.  They therefore carried on this infinite conversation
with the getty and login processes.  For example, login would write "login:"
to the TC, the TC would respond "invalid command", then login would
prompt for a password and wait 60, and then write the incriminating
string "Login timed out after 60 seconds", and so on.

The DMZ driver is a 4.3 driver from Chris Torek.

Since directories are being written on also, something not allowed
by user processes, the kernel is suspect.  My only guess is that
buffers are being screwed up somewhere and disk drivers (UDA50)
are writing bogus stuff out.

We are now rebuilding, hoping that the DMZ-TC cycling was responsible.

Please mail me any advice.
Thank-you.

David Melman
SDC - Santa Monica
A UNISYS COMPANY :^)

UUCP: {hplabs,ihnp4}!sdcrdcf!davem