Can't overwrite a particular swap partition

[Bruce Cran]

RW wrote:
> I have two swap partitions, ad4s1b is part of my main slice, and ad6s1b
> is on a second drive. The permissions are the same, but I can't
> overwrite the second one. The same thing happens whether I use swapoff
> or reboot into single user mode.
> 
> What's the difference?
> 
> # dd if=/dev/random of=/dev/ad4s1b bs=1m
> dd: /dev/ad4s1b: end of device
> 4097+0 records in
> 4096+0 records out
> 4294967296 bytes transferred in 245.745739 secs (17477281 bytes/sec)
> 
> # dd if=/dev/random of=/dev/ad6s1b bs=1m
> dd: /dev/ad6s1b: Operation not permitted
> 1+0 records in
> 0+0 records out
> 0 bytes transferred in 0.053829 secs (0 bytes/sec)
> 
> # ls -l /dev/ad*1b
> crw-r-----  1 root  operator    0, 125 Oct 25 00:25 /dev/ad4s1b
> crw-r-----  1 root  operator    0, 132 Oct 24 20:23 /dev/ad6s1b
>

This looks like a geom permission problem, though it sounds like it 
should't be occurring.  Does setting

kern.geom.debugflags=16

solve this?

--
Bruce