kernel/1431: CTRL-ALT-DEL drops kernel to ddb.

[morten@hotpost.dk]

>Number:         1431
>Category:       kernel
>Synopsis:       Using CTRL-ALT-DEL in console drops kernel to ddb.
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Oct  3 12:00:02 MDT 2000
>Last-Modified:
>Originator:     Morten Liebach
>Organization:
>Release:        OpenBSD 2.8-current 2000.09.29 snapshot.
>Environment:
	System      : OpenBSD 2.8
	Architecture: OpenBSD.i386
	Machine     : i586, AMD K2-6, 64MB RAM.
>Description:
	Uncommenting the line:
		#machdep.kbdreset=1
	in /etc/sysctl.conf, reboot, and then test whether CTRL-ALT-DEL
	works makes the kernel crash with the message:

	uvm_fault(0xe5ae4d48, 0xdead0000, 0, 1) -> 5
	kernel: page fault trap, code=0
	Stopped at	_psignal+0x35:  testb	$0x8,0x2d(%ebx)
	ddb> _

	and then the the cursor just blinks away ...
	It doesn't matter whether someone is logged in to the tty or not.

>How-To-Repeat:
	uncomment the last line in /etc/sysctl.conf so it says:
		machdep.kbdreset=1
	and reboot. In the console do a CTRL-ALT-DEL.
>Fix:
	Put a # in front of `machdep.kbdreset=1' in /etc/sysctl.conf again.
	Then reboot.
	OR
	Don't push CTRL-ALT-DEL in the console.

>Audit-Trail:
>Unformatted: