KQUEUE/TTY related panic

[Maxim Maximov]

Hello.

	Just got a panic when dropped into DDB by Ctrl-Alt-Esc, issued 'show 
witness', pressed ScrLk, pressed PgUp ten times, then PgDn. Then 
released cursor by pressing ScrLk again.

db> panic: blockable sleep lock (sleep mutex) tty @ 
/usr/src/sys/kern/kern_event.c:1450
cpuid = 0
boot() called on cpu#0
Uptime: 2m22s

	Machine freezes completely here. Keys didn't work. Reset helped.
	Tried exactly the same actions after reboot - exactly same effect.
	Machine is SMP, HTT, WITNESS enabled, today's HEAD.
	Dmesg is at http://mcsi.pp.ru/dmesg.boot

-- 
Maxim Maximov