Fatal trap 12: page fault while in kernel mode
cpuid = 1; lapic id = 1
fault virtual address	= 0x0
fault code		= supervisor read data, page not present
instruction pointer	= 0x8:0xffffffff80647bad
stack pointer	        = 0x10:0xfffff8008e15d7d0
frame pointer	        = 0x10:0xfffff8008e15d830
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= Idle
current thread          = pri 28 
kernel: type 12 trap, code=0

CPU1 stopping CPUs: 0x0000003d
 stopped
Stopped at      lockmgr_exclusive+0x5d: orl     (%r14),%esi
db> trace
lockmgr_exclusive() at lockmgr_exclusive+0x5d 0xffffffff80647bad
uether_ifdetach() at uether_ifdetach+0x2f 0xffffffff8261eb6f
cdce_detach() at cdce_detach+0x2a 0xffffffff8260007a
cdce_attach() at cdce_attach+0x56b 0xffffffff82600b7b
device_doattach() at device_doattach+0x3af 0xffffffff8068dbef
usb_probe_and_attach() at usb_probe_and_attach+0x176 0xffffffff80a46306
uhub_explore() at uhub_explore+0x231 0xffffffff80a4d3b1
usb_bus_explore() at usb_bus_explore+0xd0 0xffffffff80a61520
usb_process() at usb_process+0x76 0xffffffff80a512a6
db> bt
No such command
db> call dumpsys
Physical memory: 4060 MB
Dumping 525 MB: 510 494 478 462 446 430 414 398 382 366 350 334 318 302 286 270 254 238 222 206 190 174 158 142 126 110 94 78 62 46 30 14
Dump complete
ffffffff81142e60
db>