kern/41113: crash with ccd driver

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>Number:         41113
>Category:       kern
>Synopsis:       crash with ccd driver
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Mar 31 21:55:00 +0000 2009
>Originator:     Andrew Doran
>Release:        5.0
>Organization:
The NetBSD Project
>Environment:
i386 SMP
>Description:
ccd increments v_numoutput without holding v_interlock.
Hence, it can get out of sync and you get a panic from vwakeup
(neg numoutput).

>How-To-Repeat:
Use ccd, even on a UP system.
>Fix:
Lock ccd... Have changes to do this, filing PR so I can remember to
complete them and check them in.