Kernel Oops

pi@raspberrypi:~$ [ 4115.299888] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 4115.314240] pgd = c0004000
[ 4115.322904] [00000000] *pgd=00000000
[ 4115.332334] Internal error: Oops: 17 [#1] PREEMPT ARM

Entering kdb (current=0xccca0320, pid 2197) Oops: (null)
due to oops @ 0xc0298260

Pid: 2197, comm:          kworker/u:3
CPU: 0    Not tainted  (3.6.11+ #371)
PC is at dwc_otg_hcd_urb_enqueue+0x70/0x184
LR is at dwc_otg_hcd_urb_enqueue+0x5c/0x184
pc : [<c0298260>]    lr : [<c029824c>]    psr: 60000013
sp : ccec7d00  ip : ccec7c28  fp : cceb72e0
r10: 00000000  r9 : cd97c838  r8 : cd96ca80
r7 : cceba7e0  r6 : cd97c850  r5 : 00000000  r4 : cd96c980
r3 : 00000000  r2 : 00000000  r1 : 00000000  r0 : f3000806
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Control: 00c5387d  Table: 0db24008  DAC: 00000017
[<c0013a7c>] (unwind_backtrace+0x0/0xf0) from [<c0072a98>] (kdb_dumpregs+0x28/0x50)
[<c0072a98>] (kdb_dumpregs+0x28/0x50) from [<c0074e1c>] (kdb_main_loop+0x3a8/0x6fc)
[<c0074e1c>] (kdb_main_loop+0x3a8/0x6fc) from [<c0077500>] (kdb_stub+0x154/0x380)
[<c0077500>] (kdb_stub+0x154/0x380) from [<c006e634>] (kgdb_handle_exception+0x1f8/0x668)
[<c006e634>] (kgdb_handle_exception+0x1f8/0x668) from [<c00131fc>] (kgdb_notify+0x24/0x40)
[<c00131fc>] (kgdb_notify+0x24/0x40) from [<c039b4d4>] (notifier_call_chain+0x44/0x84)
[<c039b4d4>] (notifier_call_chain+0x44/0x84) from [<c039b54c>] (__atomic_notifier_call_chain+0x38/0x4c)
[<c039b54c>] (__atomic_notifier_call_chain+0x38/0x4c) from [<c039b578>] (atomic_notifier_call_chain+0x18/0x20)
[<c039b578>] (atomic_notifier_call_chain+0x18/0x20) from [<c039b5b8>] (notify_die+0x38/0x44)
[<c039b5b8>] (notify_die+0x38/0x44) from [<c001102c>] (die+0xc4/0x39c)
[<c001102c>] (die+0xc4/0x39c) from [<c039430c>] (__do_kernel_fault.part.9+0x54/0x74)
[<c039430c>] (__do_kernel_fault.part.9+0x54/0x74) from [<c039b1e4>] (do_page_fault+0x1e8/0x3ec)
[<c039b1e4>] (do_page_fault+0x1e8/0x3ec) from [<c000832c>] (do_DataAbort+0x34/0x98)
[<c000832c>] (do_DataAbort+0x34/0x98) from [<c03999d8>] (__dabt_svc+0x38/0x60)
Exception stack(0xccec7cb8 to 0xccec7d00)
7ca0:                                                       f3000806 00000000
7cc0: 00000000 00000000 cd96c980 00000000 cd97c850 cceba7e0 cd96ca80 cd97c838
7ce0: 00000000 cceb72e0 ccec7c28 ccec7d00 c029824c c0298260 60000013 ffffffff
[<c03999d8>] (__dabt_svc+0x38/0x60) from [<c0298260>] (dwc_otg_hcd_urb_enqueue+0x70/0x184)
[<c0298260>] (dwc_otg_hcd_urb_enqueue+0x70/0x184) from [<c0298e7c>] (dwc_otg_urb_enqueue+0x21c/0x2f0)
[<c0298e7c>] (dwc_otg_urb_enqueue+0x21c/0x2f0) from [<c0273344>] (usb_hcd_submit_urb+0xbc/0x77c)
[<c0273344>] (usb_hcd_submit_urb+0xbc/0x77c) from [<c0275828>] (usb_start_wait_urb+0x44/0xbc)
[<c0275828>] (usb_start_wait_urb+0x44/0xbc) from [<c0275a54>] (usb_control_msg+0xb4/0xe8)
[<c0275a54>] (usb_control_msg+0xb4/0xe8) from [<bf0b8e48>] (rt2x00usb_vendor_request+0x98/0x128 [rt2x00usb])
[<bf0b8e48>] (rt2x00usb_vendor_request+0x98/0x128 [rt2x00usb]) from [<bf0b8fd4>] (rt2x00usb_vendor_req_buff_lock+0xc8/0x108 [rt2x00usb])
[<bf0b8fd4>] (rt2x00usb_vendor_req_buff_lock+0xc8/0x108 [rt2x00usb]) from [<bf0b9078>] (rt2x00usb_vendor_request_buff+0x64/0xb0 [rt2x00usb])
[<bf0b9078>] (rt2x00usb_vendor_request_buff+0x64/0xb0 [rt2x00usb]) from [<bf0d70f0>] (rt2x00usb_register_write+0x34/0x3c [rt2800usb])
[<bf0d70f0>] (rt2x00usb_register_write+0x34/0x3c [rt2800usb]) from [<bf0c8478>] (rt2800_config_txpower+0x3f0/0x460 [rt2800lib])
[<bf0c8478>] (rt2800_config_txpower+0x3f0/0x460 [rt2800lib]) from [<bf0aa718>] (rt2x00link_agc+0x28/0x54 [rt2x00lib])
<bf0aa718>] (rt2x00link_agc+0x28/0x54 [rt2x00lib]) from [<c0035024>] (process_one_work+0x150/0x40c)
[<c0035024>] (process_one_work+0x150/0x40c) from [<c0035604>] (worker_thread+0x150/0x498)
[<c0035604>] (worker_thread+0x150/0x498) from [<c003a7c8>] (kthread+0x88/0x94)
[<c003a7c8>] (kthread+0x88/0x94) from [<c000e9fc>] (kernel_thread_exit+0x0/0x8)