panic when unplugging a mounted usb camera

Hi,

A somewhat annoying occurance in -current; I get a panic if I leave the
camera device mounted when I unplug it and subsequently try to unmount
the device or reboot the system.  I did some digging and it seems the
dacleanup() function isnt being called because periph->refcount is 1.  I
spoke to another person who uses the da driver for their camera and
their's cleans up fine when mounted.

Aug 23 21:15:29 icecold kernel: umass0: Fuji Photo Film USB Mass
Storage, rev 1.10/10.00, addr 2 
Aug 23 21:15:29 icecold kernel: da0 at umass-sim0 bus 0 target 0 lun 0 
Aug 23 21:15:29 icecold kernel: da0: <FUJIFILM USB-DRIVEUNIT 1.00> 
Removable Direct Access SCSI-0 device 
Aug 23 21:15:29 icecold kernel: da0: 1.000MB/s transfers 
Aug 23 21:15:29 icecold kernel: da0: 31MB (64000 512 byte sectors: 
64H 32S/T 31C)

Thats the camera, for reference.

Aug 23 21:15:31 icecold kernel: umass0: at uhub1 port 2 (addr 2)
disconnected
Aug 23 21:15:31 icecold kernel: invalidate called...
Aug 23 21:15:31 icecold kernel: (da0:umass-sim0:0:0:0): lost device
Aug 23 21:15:31 icecold kernel: returned from inval
Aug 23 21:15:31 icecold kernel: refcount is 0, freeing
Aug 23 21:15:31 icecold kernel: periph not null, calling..0xc0159bd0
Aug 23 21:15:31 icecold kernel: we got to dacleanup..
Aug 23 21:15:31 icecold kernel: (da0:umass-sim0:0:0:0): removing device
entr

Thats what I get when I remove the device and it is unmounted(with my
debugging additions).

Aug 23 21:16:12 icecold kernel: umass0: at uhub1 port 2 (addr 2)
disconnected
Aug 23 21:16:12 icecold kernel: invalidate called...
Aug 23 21:16:12 icecold kernel: (da0:umass-sim0:0:0:0): lost device
Aug 23 21:16:12 icecold kernel: returned from inval
Aug 23 21:16:12 icecold kernel: refcount is 1


Thats what I get when I remove the device and it is mounted.

Please do let me know if I can provide any further information.

Regards,

Stuart Walsh