内核异常kernel panic该如何定位？
异常信息：
[ 3.970213] Switched to NOHz mode on CPU #0
[ 3.987118] Unhandled kernel unaligned access[#1]:
[ 3.996675] Cpu 0
[ 4.000556] zero[$0]=00000000 at[$1]=00000075 v0[$2]=ffffffed v1[$3]=00000001
[ 4.016275] a0[$4]=ffffffed a1[$5]=806c105c a2[$6]=8077e6d0 a3[$7]=00000000
[ 4.031989] t0[$8]=806c105d t1[$9]=00000001 t2[$10]=8075b0c0 t3[$11]=031c0084
[ 4.047705] t4[$12]=8075c1b0 t5[$13]=00000007 t6[$14]=40008100 t7[$15]=00000000
[ 4.063421] s0[$16]=ffffffed s1[$17]=00000001 s2[$18]=88113400 s3[$19]=80759518
[ 4.079137] s4[$20]=80759520 s5[$21]=80900000 s6[$22]=00000000 s7[$23]=88113408
[ 4.094853] t8[$24]=00000000 t9[$25]=8001a484 k0[$26]=80838708 k1[$27]=80015820
[ 4.110569] gp[$28]=88030000 sp[$29]=88031d58 s8[$30]=00000000 ra[$31]=80011f78
[ 4.126283] Hi : 00000000
[ 4.132107] Lo : 00000000
[ 4.137971] epc : 802b8ee0 regulator_is_enabled+0x14/0x8c
[ 4.149243] Not tainted
[ 4.154899] ra : 80011f78usb_audio_select+0x38/0xc0
[ 4.165485] Status: 10000c03 KERNEL EXL IE
[ 4.174486] Cause : 00800010
[ 4.180316] This is Address error exception (load or instruction fetch)
[ 4.193736] BadVA : 00000019
[ 4.199566] PrId : 7ae1024f (Ingenic Xburst)
[ 4.208396] Modules linked in:
[ 4.214578] Process swapper (pid: 1, threadinfo=88030000, task=88028000,tls=00000000)
[ 4.230646] Stack : 00000001 88113400 80759518 80759520 80900000 ffffffed00000001 80011f78
[ 4.247238] 88113400 8034bbc8 00000000 0000000088114980 00000001 88114980 8034bd58
[ 4.264190] 8075952880759554 807823c8 0000000000000000 8029f7dc 807823c8 80759520
[ 4.281142] 8084000080759554 807823c8 0000000000000000 00000000 00000000 8029fb40
[ 4.298094] 88112a80 8022cd40 88114700 8811470080759520 807823c8 8075955488114700
[ 4.315046] ...
[ 4.320348] Call Trace:
[ 4.325293] [<802b8ee0>]regulator_is_enabled+0x14/0x8c
[ 4.335897] [<80011f78>] usb_audio_select+0x38/0xc0
[ 4.345790] [<8034bd58>] dwc2_jz_probe+0x170/0x468
[ 4.355501] [<8029fb40>] driver_probe_device+0xa4/0x1e0
[ 4.366092] [<8029fd38>] __driver_attach+0xbc/0xc4
[ 4.375802] [<8029e6d8>] bus_for_each_dev+0x4c/0xa8
[ 4.385690] [<8029f3a0>]bus_add_driver+0x1d4/0x2b8
[ 4.395579] [<802a04c0>] driver_register+0x90/0x1a0
[ 4.405468] [<80010564>] do_one_initcall+0x164/0x1f0
[ 4.415526]
[ 4.418526]
[ 4.418530] Code: afbf001c afb10018 00808021 <8c84002c> 0c17a987 24840040 8e04002c 8c820000 8c42000c
[ 4.441405] ---[ end trace 13b17594e01c34f1 ]---
[ 4.450749] Kernel panic - not syncing: Attempted to kill init!
[ 4.462707] Rebooting in 3 seconds..Restarting after 4 ms
确认异常位置：
异常发生的函数名及其在函数里的位置：epc :802b8ee0 regulator_is_enabled+0x14/0x8c
异常所在函数的上一级函数名称是：ra : 80011f78usb_audio_select+0x38/0xc0
如何找到该异常函数据所在的文件及位置：
1）编译含debug info的内核包，打开如下选项：
CONFIG_DEBUG_KERNEL=y
CONFIG_DEBUG_INFO=y
2）用gdb调试vmlinux，通过b *0x80011f78打印出异常的代码位置：
mipsel-linux-android-gdb kernel/vmlinux
(gdb) b *0x80011f78
Breakpoint 1 at 0x80011f78: filearch/mips/xburst/soc-m200/chip-m200/glass/common/audio_usb_select.c, line 90.
Ps:gdb在android的交叉编译工具包里，prebuilts/gcc/linux-x86/mips/mipsel-linux-android-4.7/bin/mipsel-linux-android-gdb，我列举的是mips，如果是arm，则选arm的工具。