Why do you want bluetty?
If you want bluetooth support, maybe you should select from top level menuconfig,
Networking --> [*] Bluetooth subsystem support ---> Bluetooth device drivers ---> [*] HCI USB driver
The isp116x driver does not use DMA. It looks like the hcd driver crashed after detecting port
<div class='quotetop'>QUOTE </div>
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hub 1-0:1.0: 2 ports detected
scheduling while atomic: swapper/0x00000002/1[/b]
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You should enable DEBUG in your driver, or add some printk() to find out.
You should try out the 2.6.15.6 kernel in the update of the buildroot guide.