4.2, berknet and crashes

[lee at unmvax.UUCP]

Subject: Berknet on a dh crashes the system
Index:	.../sys/h/bk.h
	    .../sys/vaxuba/dh.c .../sys/sys/tty.c .../sys/sys/tty_bk.c 4.2BSD

Description:
	We have two DH lines dedicated to berknet. These are used
	fairly heavily. The machine (a 780) cannot stay up for
	more than ten days. The crash is always on the line

	*tp->t_cp++ = c;

	at the instruction

	cvtlb	r10, *4(r11)

	in the BKINPUT macro from .../sys/h/bk.h

	No crash dumps are taken; nor are the disks synched. Just
	alot of "protection fault" panics and then a reboot.

	It looks like the buffer gets deallocated.
	However, I cannot find where this might be happening.

	We have other machines using berknet on DZ's and they have
	never had the problem. Strange...
Repeat-By:
	Got me!?




 Any help in, either the form of a fix or in modifying the routines
involved in a crash so that I can get a dump would be appreciated.

-- 
			--Lee (Ward)
			{ucbvax,convex,gatech,pur-ee}!unmvax!lee