Panic when removing Airprime PC5220 card (usb hub).

[David Andersen]

I'm hacking up a quick and dirty driver for the AirPrime PC5220 (EVDO / 
1xRTT) card, but I'm encountering a crash unrelated to my driver.  The 
card is a pc card that presents itself as a USB hub with one device 
hanging off of it.  Removing the card from the system causes a kernel 
panic.  The backtrace looks something like:

kobj_delete+0xb
device_delete_child + 0x98
usb_disconnect_port + 0xf3
uhub_detach + 0x7a
device_detach + 0x57
device_delete_child + 0x2b
device_delete_child + 0x17
ohci_pci_detach + 0x85
device_detach + 0x57
cardbus_detach_card + 0x93
cbb_removal + 0x6f
cbb_event_thread + 0xb6
fork_exit + 0x74
fork_trampoline() + 0x8
trap 0x1 eip = 0 esp = 0xedf66d6c

(sorry for the poor formatting;  I don't have serial debug support at 
the moment to copy-paste. :)

If someone with more familiarity with the device framework looks at 
this and says, "ah!  I know exactly what that bug is," I'd love it if 
you'd let me know so I can go back to the usb side of things.  For my 
application, I'm actually quite content saying "don't remove the card," 
but I think that most users of this card are mobile, and would like to 
be able to disconnect it.

(please CC: me;  I'm not on the list any more).

Thanks!

   -Dave