Repatable panic in 7.0-beta1

I get this repeatable panic in 7.0-BETA1 whenever I connect my new
USB external hdd. This is the backtrace from kgdb on the crash file.
There is no problem if I boot the computer with the drive attached,
but if I unplug and replug in, it will panic again, like it always
does when I plug it into a running system.

I'll gladly provide more info, if someone tells me what to do.


#0  doadump () at pcpu.h:195
#1  0xc074ff67 in boot (howto=260) at
/usr/src/sys/kern/kern_shutdown.c:409
#2  0xc0750229 in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:563
#3  0xc0a131fc in trap_fatal (frame=0xd8ed9974, eva=0) at
/usr/src/sys/i386/i386/trap.c:872
#4  0xc0a13480 in trap_pfault (frame=0xd8ed9974, usermode=0, eva=0)
at /usr/src/sys/i386/i386/trap.c:785
#5  0xc0a13df5 in trap (frame=0xd8ed9974) at
/usr/src/sys/i386/i386/trap.c:463
#6  0xc09f9e1b in calltrap () at /usr/src/sys/i386/i386/exception.s:139
#7  0xc0466f6b in xpt_done (done_ccb=0xc34cf800) at
/usr/src/sys/cam/cam_xpt.c:4856
#8  0xc046d21e in probedone (periph=0xc4d3fe00, done_ccb=Variable
"done_ccb" is not available.
) at /usr/src/sys/cam/cam_xpt.c:6331
#9  0xc0468fb1 in camisr_runqueue (V_queue=Variable "V_queue" is not
available.
) at /usr/src/sys/cam/cam_xpt.c:7255
#10 0xc046d82f in xpt_bus_deregister (pathid=1) at
/usr/src/sys/cam/cam_xpt.c:4442
#11 0xc06c7690 in umass_cam_detach_sim (sc=0xc48f8000) at
/usr/src/sys/dev/usb/umass.c:2694
#12 0xc06c773d in umass_detach (self=0xc39c6a00) at
/usr/src/sys/dev/usb/umass.c:1542
#13 0xc0770f38 in device_detach (dev=0xc39c6a00) at device_if.h:212
#14 0xc06cd932 in usb_disconnect_port (up=0xc34b6c30,
parent=0xc34caa80) at /usr/src/sys/dev/usb/usb_subr.c:1380
#15 0xc06c4c0e in uhub_explore (dev=0xc3489c00) at
/usr/src/sys/dev/usb/uhub.c:462
#16 0xc06cbae5 in usb_discover (v=Variable "v" is not available.
) at /usr/src/sys/dev/usb/usb.c:724
#17 0xc06ccad7 in usb_event_thread (arg=0xc34a0d00) at
/usr/src/sys/dev/usb/usb.c:440
#18 0xc0730549 in fork_exit (callout=0xc06cca20 <usb_event_thread>,
arg=0xc34a0d00, frame=0xd8ed9d38)
    at /usr/src/sys/kern/kern_fork.c:796
#19 0xc09f9e90 in fork_trampoline () at
/usr/src/sys/i386/i386/exception.s:205


uname -a says:

FreeBSD weld.ej2.thelosingend.net 7.0-BETA1 FreeBSD 7.0-BETA1 #1:
Wed Oct 24 10:08:38 CEST 2007
sveinhal_at_weld.ej2.thelosingend.net:/usr/obj/usr/src/sys/GENERIC  i386