Panic: mutex Giant not owned cam_xpt.c :4799

Just decided to try out the 0907 snapshot of -CURRENT (amd64) and it 
won't boot off the install CD

Thought I would post as much info as I could for interested parties. I 
have to copy by hand, so I will try to include as much as I can.

panic: mutex Giant not owned at /usr/src/sys/cam/cam_xpt.c :4799

This error occurs right after "md0: Preloaded image </boot/mfsroot> ....

The motherboard is an Asus P5M2-R, with dual bge ethernets (on mb), a 
Adaptec 3405 SATA/SAS RAID PCI-e  card (aac driver), and has an Intel 
Q6600 quad core. 4GB of RAM. You will soon see why I included the 
information on the Adaptec card.

This hardware works fine using 6.2-RELEASE p8 -- well, at least i386 
does. This system has a modified src/sys/dev/aac which includes the 
vendor ID info for the 3405/3805 cards and has no problems booting (and 
running), detecting Adaptec card, etc.

I also have a CD with the same snapshot (CURRENT, 0907) in an i386 
version (not AMD64) which appears to produce the same error.

Upon the panic, the system entered the debugger and I typed "trace" to 
get the following from AMD64 snapshot:

Tracing pid 26 tid 100026 td 0xffffff0002245680
kdb_enter() at kdb_enter+0x31
panic() at panic+0x173
_mtx_assert() at _mtx_assert+0xd6
xpt_release_simq() at xpt_release_simq()+0x27
aac_alloc_commands() at aac_alloc_commands()+0x156
aac_command_thread() at aac_command_thread()+0xe5
fork_exit() at fork_exit+0x12a
fork_trampoline() at fork_trampoline()+0xe
--- trap 0, rip = 0, rsp = 0xffffffffac6fdd30, rbp = 0 ---


Hope this helps someone,

Steve