machine got stuck in "[diagnostic] cache_lock: blocked on 0xe4008260 "ttyp8" after issuing reboot (after remote update from 1.2.0 to 1.2.1)

[Matthew Dillon]

:Hello!
:
:	I was remotely updating 1.2.0 machine to 1.2.1. Basically I compiled 
:world, compiled kernel, installed kernel and recompiled kernel again 
:with PF and ALTQ and installed it. After issuing reboot I could not 
:reconnect. After some driving I discovered that machine did not reboot 
:itself, because it got stuck (it was not hung!) in "[diagnostic] 
:cache_lock: blocked on 0xe4008260 "ttyp8".
:
:Basically output on screen was like this:
:...
:"[diagnostic] cache_lock: blocked on 0xe4008260 "ttyp8"
:
:and stayed there - until I pressed Ctrl-Alt-Del:
:...
:Toma¾

    Something is holding onto a cache lock while blocked on ttyp8, which
    is not supposed to happen (but obviously did).  If this happens again,
    getting a kernel dump would give me exactly what I need to find and
    fix the problem.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>