kern/46841: vnconfig on sparse file crashes the kernel.

[christos%netbsd.org@localhost]

>Number:         46841
>Category:       kern
>Synopsis:       vnconfig on sparse file crashes the kernel.
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Aug 26 10:50:01 +0000 2012
>Originator:     Christos Zoulas
>Release:        NetBSD 6.99.10
>Organization:
        Flakey Machines
>Environment:
System: NetBSD bulky.astron.com 6.99.10 NetBSD 6.99.10 (BULKY) #18: Sat Aug 25 
18:04:24 EEST 2012 
christos%bulky.astron.com@localhost:/usr/src/sys/arch/amd64/compile/BULKY amd64
Architecture: x86_64
Machine: amd64
>Description:
        When I run the following commands, the machine crashes in
        pool_init. My kernel has DEBUG/LOCKDEBUG/DIAGNOSTIC

        dd if=/dev/zero of=disk seek=1g count=1
        vnconfig -c vnd0 disk

        Dies in vndioctl->pool_init

>How-To-Repeat:
        See above
>Fix:
        Others can't reproduce this. Maybe my machine is flakey?