kern/46737: ucom (at least at uplcom) unusable under current SMP

[martin%NetBSD.org@localhost]

>Number:         46737
>Category:       kern
>Synopsis:       ucom (at least at uplcom) unusable under current SMP
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 24 07:45:00 +0000 2012
>Originator:     Martin Husemann
>Release:        NetBSD 6.99.9
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD beasty.aprisoft.de 6.99.9 NetBSD 6.99.9 (NIGHT-OWL) #103: Sun 
Jul 15 13:43:35 CEST 2012 
martin%night-owl.duskware.de@localhost:/usr/src/sys/arch/amd64/compile/NIGHT-OWL
 amd64
Architecture: x86_64
Machine: amd64
>Description:

Using ucom@uplcom in -current with a SMP kernel is very crashy.
The kernel crashes ~instantly on bulk input form the serial connection
and when you unplug the device while the tty is open.

Booting -1 works around the problem.

>How-To-Repeat:
n/a
>Fix:
n/a