概述
在实践项目中出现内核跑死，具体打印如下
Unable to handle kernel paging request fordata at address 0xc00000200081a940
Faulting instruction address:0x800000000517ae40
Oops: Kernel access of bad area, sig: 11[#1]
PREEMPT SMP NR_CPUS=24 CoreNet Generic
Modules linked in: ossmod(O) tipc(O)bcmapi(O) linux_bcm_net(O) linux_bcm_diag(O) linux_bcm_core(O)linux_uk_proxy(O) linux_kernel_bde(O) robo_spi(O)
CPU: 1 PID: 3711 Comm: SCHE7_1 Tainted:G W O 3.10.55-EMBSYS-CGEL-5.01.30.P0.B4-svn52164#1
task: c000000140ce0080 ti: c000000140cec000task.ti: c000000140cec000
NIP: 800000000517ae40 LR: 800000000517add0CTR: 0000000000000000
REGS: c000000140cef1d0 TRAP: 0300 Tainted: G W O (3.10.55-EMBSYS-CGEL-5.01.30.P0.B4-svn52164)
MSR: 0000000080029000 <CE,EE,ME> CR: 44004488 XER: 20000000
SOFTE: 1
DEAR: c00000200081a940, ESR:0000000000000000
GPR00: 000000000000000a c000000140cef45080000000051ad920 80000000051ad920
GPR04: c000000140cef657 000000000000003880000000051a7c2d 0000000000000003
GPR08: 80000000051ad920 c00000200081a938c00000000081a958 80000000051ad920
GPR12: 800000000519c350 c00000000fff478000000000000000ff 00000000000000ff
GPR16: 0000000000000000 000000000000d8800000000000404007 0000000000000000
GPR20: 00000000000000d8 0000000000000080000000001026ada8 000000001026a638
GPR24: 00000000102554f0 00003fff8988c2280000000000001142 0000000000000ebe
GPR28: 0000000000000038 000000000000000000000000ffffffff c000000140cef950
NIP [800000000517ae40] .BCControl+0xa8fc/0x13dc4[bcmapi]
/*由此出错点在BCControl第0xa8fc字节处，函数体大小为0x13dc4*/
LR [800000000517add0].BCMXGSControl+0xa88c/0x13dc4 [bcmapi]
Call Trace:
[c000000140cef450] [800000000517ad98].BCMXGSControl+0xa854/0x13dc4 [bcmapi] (unreliable)
[c000000140cef8d0] [8000000005184c8c].bsp_bcmxgs_ioctl+0x984/0x9e4 [bcmapi]
[c000000140cefbd0] [8000000005184d18].bsp_bcmxgs_unlockedIoCtl+0x2c/0x3c [bcmapi]
[c000000140cefc40] [c00000000013c510].vfs_ioctl+0x3c/0x74
[c000000140cefcb0] [c00000000013d180] .do_vfs_ioctl+0x6f4/0x74c
[c000000140cefd80] [c00000000013d234].SyS_ioctl+0x5c/0xa4
[c000000140cefe30] [c000000000000598]syscall_exit+0x0/0x8c
Instruction dump:
48021541 e8410028 3d620000 e92b801081490000 7d4ae214 554a04fe 91490000
3c620000 e9438120 7bc92ea4 7d2a4a14<e9290008> 2fa90000 40fe011c 38610318
---[ end trace cf847998a4cea8d7 ]---
知道了出错的点，需要借助反汇编及addr2line定位到具体的出错代码，步骤如下：
1. 反汇编
/opt/okk/20150617/ppc_gcc4.8.2_glibc2.18.0_multi/bin/ppc64_e5500-hardfloat-linux-gnu-objdump-S bcmdddapi.ko >bcmdddapi_objdump.txt
2. 由上面的oops可知，出错点在BCControl+0xa8fc
由反汇编可知BCControl函数地址是0x0000000000002544（此处地址是十六进制）
0x0000000000002544+0xa8fc = 0x000000000000CE40
| 0000000000002544 <.BCControl>: //函数起始地址 2544: 7c 08 02 a6 mflr r0 2548: f8 01 00 10 std r0,16(r1) 254c: 7d 80 00 26 mfcr r12 2550: fa a1 ff a8 std r21,-88(r1) 2554: fa c1 ff b0 std r22,-80(r1) , . . ce10: 48 00 00 01 bl ce10 <.BCMXGSControl+0xa8cc> ce14: 60 00 00 00 nop ce18: 3d 62 00 00 addis r11,r2,0 ce1c: e9 2b 00 00 ld r9,0(r11) ce20: 81 49 00 00 lwz r10,0(r9) ce24: 7d 4a e2 14 add r10,r10,r28 ce28: 55 4a 04 fe clrlwi r10,r10,19 ce2c: 91 49 00 00 stw r10,0(r9) ce30: 3c 62 00 00 addis r3,r2,0 ce34: e9 43 00 00 ld r10,0(r3) ce38: 7b c9 2e a4 rldicr r9,r30,5,58 ce3c: 7d 2a 4a 14 add r9,r10,r9 ce40: e9 29 00 08 ld r9,8(r9) //出错点 ce44: 2f a9 00 00 cmpdi cr7,r9,0 ce48: 40 fe 01 1c bne+ cr7,cf64 <.BCMXGSControl+0xaa20> ce4c: 38 61 03 18 addi r3,r1,792 ce50: 48 00 00 01 bl ce50 <.BCMXGSControl+0xa90c> ce54: 60 00 00 00 nop |
3. 由以上点已经可以知道出错的地址是0x000000000000CE40，对应的汇编代码是
| ce40: e9 29 00 08 ld r9,8(r9) |
但是汇编看起来还是比较晦涩的，可以借助addr2line转换成行号，方法是，
| addr2line -e 进程名 地址 -f |
如下
| [root@A20006253bgx]# /opt/okk/20130617/ppc_gcc4.8.2_glibc2.18.0_multi/bin/ppc64_e5500-hardfloat-linux-gnu-addr2line -e bcmddapi.ko000000000000CE40 -f BCControl /home/workspace/uppv2.1_dailybuild/code/xtf/bsp/source/cpus/linux/config-linux-3.10.55-cgel/T1020/linux/drivers/bsp/source/boards/NCCCC/T1020/linux/../../../../sodaV5/sp/ethswitch/bcmxgs5.7.0/ksource/ngx_bcmxgs_api.c:2234 [root@A20006253 bgx]# |
由此可知出错地方是在ngx_bcmxgs_api.c文件的第2234行
最后
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