smartmontools/smartctl regression - CAMGETPASSTHRU ioctl failed

I know there have been some recent changes in the area (although TBH I  
don't know what CAM is, so...). It used to work a few weeks ago when I  
last checked, but now I get this:

# smartctl -A /dev/da0
smartctl version 5.38 [amd64-portbld-freebsd8.0] Copyright (C) 2002-8  
Bruce Allen
Home page is http://smartmontools.sourceforge.net/

smartctl: cam_lookup_pass: CAMGETPASSTHRU ioctl failed
cam_lookup_pass: No such file or directory
cam_lookup_pass: either the pass driver isn't in your kernel
cam_lookup_pass: or da0 doesn't exist
Standard Inquiry (36 bytes) failed [Operation not permitted]
Retrying with a 64 byte Standard Inquiry
smartctl: cam_lookup_pass: CAMGETPASSTHRU ioctl failed
cam_lookup_pass: No such file or directory
cam_lookup_pass: either the pass driver isn't in your kernel
cam_lookup_pass: or da0 doesn't exist
Standard Inquiry (64 bytes) failed [Operation not permitted]
A mandatory SMART command failed: exiting. To continue, add one or  
more '-T permissive' options.
---------------
A rebuild of smartmontools did nothing. Am I missing a kernel option  
or something? I'm running GENERIC plus DTRACE minus WITNESS/ 
INVARIANTS, no other changes.

Regards,
Thomas