kern/40526: following newfs_udf example causes a kernel panic

[pooka%iki.fi@localhost]

>Number:         40526
>Category:       kern
>Synopsis:       following newfs_udf example causes a kernel panic
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jan 31 16:40:00 +0000 2009
>Originator:     Antti Kantee
>Release:        
>Organization:
>Environment:
5.0_BETA
>Description:
Following an example in newfs_udf(8) causes a KASSERT kernel panic
in kern_physio. I did not investigate if it leads to problems on
non-DIAGNOSTIC kernels.
>How-To-Repeat:
dd if=/dev/zero of=bigdisk.2048.udf seek=9999999 count=1
vnconfig -c vnd0 bigdisk.2048.udf 2048/1/1/1
newfs_udf -L bigdisk /dev/rvnd0d

>Fix:
I described the underlying technical problem in:
http://mail-index.netbsd.org/tech-kern/2008/11/25/msg003649.html

I don't know if the problem can be fixed for 5.0, especially considering
there were no responses on tech-kern, but at least the example would be
nice to remove from the man page so that no other poor soul encounters
crash-by-rtfm.