Arrays 当x23达到某个值时，strb w1、[x22、x23]导致的分段错误_Arrays_Linux_Gcc_Assembly_Arm

Arrays 当x23达到某个值时，strb w1、[x22、x23]导致的分段错误

arrays linux gcc assembly arm

Arrays 当x23达到某个值时，strb w1、[x22、x23]导致的分段错误,arrays,linux,gcc,assembly,arm,Arrays,Linux,Gcc,Assembly,Arm,在我不使用bl write函数时，当x23达到某个值（即635）时，在ARMv8汇编代码中的strb w1、[x22，x23]指令上遇到一个有趣的分段错误但是，如果使用bl指令调用写函数，则不会出现分段错误；但是程序在gdb或echo$中以“…退出代码02”结束？是2 机器： Linux alarm 3.10.65-4-pine64-longsleep#16 SMP抢占Sun 4月3日10:56:40 CEST 2016 aarch64 GNU/Linux gdb-v GNU gdb（gdb）

在我不使用bl write函数时，当x23达到某个值（即635）时，在ARMv8汇编代码中的strb w1、[x22，x23]指令上遇到一个有趣的分段错误

但是，如果使用bl指令调用写函数，则不会出现分段错误；但是程序在gdb或echo$中以“…退出代码02”结束？是2

机器： Linux alarm 3.10.65-4-pine64-longsleep#16 SMP抢占Sun 4月3日10:56:40 CEST 2016 aarch64 GNU/Linux

gdb-v GNU gdb（gdb）7.11.1

gcc版本6.1.1 20160707（gcc）

是什么导致了这种行为

  5 .bss
  6         n_array:        .byte 0
  7 .data
  8         fmt:    .asciz  "\t%d"
  9         c_array:.ascii  "73167176531330624919225119674426574742355349194934"
 10                 .ascii  "96983520312774506326239578318016984801869478851843"
 11                 .ascii  "85861560789112949495459501737958331952853208805511"
 12                 .ascii  "12540698747158523863050715693290963295227443043557"
 13                 .ascii  "66896648950445244523161731856403098711121722383113"
 14                 .ascii  "62229893423380308135336276614282806444486645238749"
 15                 .ascii  "30358907296290491560440772390713810515859307960866"
 16                 .ascii  "70172427121883998797908792274921901699720888093776"
 17                 .ascii  "65727333001053367881220235421809751254540594752243"
 18                 .ascii  "52584907711670556013604839586446706324415722155397"
 19                 .ascii  "53697817977846174064955149290862569321978468622482"
 20                 .ascii  "83972241375657056057490261407972968652414535100474"
 21                 .ascii  "82166370484403199890008895243450658541227588666881"
 22                 .ascii  "16427171479924442928230863465674813919123162824586"
 23                 .ascii  "17866458359124566529476545682848912883142607690042"
 24                 .ascii  "24219022671055626321111109370544217506941658960408"
 25                 .ascii  "07198403850962455444362981230987879927244284909188"
 26                 .ascii  "84580156166097919133875499200524063689912560717606"
 27                 .ascii  "05886116467109405077541002256983155200055935729725"
 28                 .ascii  "71636269561882670428252483600823257530420752963450"
 29         .equ    len_c_array,.-c_array
 30 .text
 31         .global main
 32         .include "mymac_armv8.s"
 33 main:
 34         nop
 35         mov w19, 0x30
 36         ldr x20,=c_array
 37         mov x21, #len_c_array
 38         sub x21, x21, 1
 39         ldr x22,=n_array
 40         mov x23, xzr
 41         1:
 42                 ldrb w1, [x20,x23]      // get ascii char
 43                 sub w1, w1, w19         // ascii value - 0x30; assumes ascii number chars only
 44                 strb w1, [x22,x23]      // store byte into n_array element
 45                 bl write
 46         add x23, x23, 1
 47         cmp x23, x21
 48         b.le 1b
 49 _exit
 50 write:
 51         push2 x29,x30
 52         ldr x0,=fmt
 53         bl printf
 54         pop2 x29, x30
 55         ret


dmesg
[23493.499193] CPU: 0 PID: 18212 Comm: ascii_array_con Tainted: G           O 3.10.65-4-pine64-longsleep #16
[23493.515436] task: ffffffc0764b4ec0 ti: ffffffc073804000 task.ti: ffffffc073804000
[23493.529484] PC is at 0x4005d0
[23493.538487] LR is at 0x7faccae8a4
[23493.547816] pc : [<00000000004005d0>] lr : [<0000007faccae8a4>] pstate: 80000000
[23493.561648] sp : 0000007ffee581a0
[23493.570951] x29: 0000007ffee581a0 x28: 0000000000000000
[23493.582394] x27: 0000000000000000 x26: 0000000000000000
[23493.593717] x25: 0000000000000000 x24: 0000000000000000
[23493.604933] x23: 000000000000027b x22: 0000000000410d85
[23493.616092] x21: 00000000000003e8 x20: 000000000041099c
[23493.627122] x19: 0000000000000030 x18: 0000000000030a41
[23493.638002] x17: 0000000000410968 x16: 0000007faccae7c8
[23493.648801] x15: 0000000000000809 x14: 0000000000000000
[23493.659629] x13: 0000000000000000 x12: 0000007face1d000
[23493.670353] x11: 0000000004000000 x10: 0101010101010101
[23493.681037] x9 : 3fffffffffffffff x8 : ffffffffffffffff
[23493.691716] x7 : 0000000004000000 x6 : 0000000000000000
[23493.702436] x5 : 0000000000000000 x4 : 0000007ffee581f8
[23493.713174] x3 : 00000000004005b0 x2 : 0000007ffee582e8
[23493.723904] x1 : 0000000000000005 x0 : 0000000000000001

[23493.746914] systemd-coredump[18214]: Failed to get COMM, falling back to the command line: No such process
[23493.762810] systemd-coredump[18214]: Failed to get EXE, ignoring: No such process

5.bss
6 n_数组：。字节0
7.数据
8 fmt:.asciz“\t%d”
9 c_数组：.ascii“73167176531330624919225119674465742355349194934”
10.ascii“96983520312774506326239578318016984801869478851843”
11.ascii“85861560789129495459501737958331952853208805511”
12.ascii“12540698747158533050715693290963295227443043557”
13.ascii“6689664895044524452316173185640309871121722383113”
14.ascii“6222989342380308135336276614282806444486645238749”
15.ascii“30358907296290491560404072390713810515859307960866”
16.ascii“7017242712188399879790879227492191699720888093776”
17.ascii“6572733300105367881220235421809751254545954752243”
18.ascii“5258490771167056013604839586446706324415722155397”
19.ascii“53697817977846174064955149290862569321978468622482”
20.ascii“83972241375657056057490261407972968652414535100474”
21.ascii“8216637048440319989000889524345065854122758866881”
22.ascii“16427171479924442928230863465674813919123162824586”
23.ascii“17866458359124566529476545682848912883142607690042”
24.ascii“24219022671055626321111110937054217506941658960408”
25.ascii“071984038509692455444362981230987879927244284909188”
26.ascii“84580156166609791919133875499200524063689912560717606”
27.ascii“05886116467109405077541002256983155200055935729725”
28.ascii“71636269561882670428252483600823257530420752963450”
29.等长c_数组，-c_数组
30.文本
31.全球主要
32.包括“mymac_armv8.s”
33主要：
34不
35 mov w19，0x30
36 ldr x20，=c_阵列
37 mov x21#透镜c#U阵列
38接头x21、x21、1
39 ldr x22，=n_阵列
40 mov x23，xzr
41         1:
42 ldrb w1，[x20，x23]//获取ascii字符
43子w1，w1，w19//ascii值-0x30；仅假定ascii数字字符
44 strb w1，[x22，x23]//将字节存储到n_数组元素中
45 bl写入
46加上x23、x23、1
47 cmp x23，x21
48 b.le 1b
49号出口
50写：
51推2 x29，x30
52 ldr x0，=fmt
53 bl printf
54 pop2 x29，x30
55 ret
启动信息
[23493.499193]CPU:0 PID:18212通信：ascii_数组污染：GO 3.10.65-4-pine64-longsleep#16
[23493.515436]任务：FFFFFF C0764B4EC0 ti:FFFFFF C073804000任务。ti:FFFFFF C073804000
[23493.529484]电脑位于0x4005d0
[23493.538487]LR位于0x7faccae8a4
[23493.547816]pc:[]lr:[]pstate:80000000
[23493.561648]sp:000000 7FFEE581A0
[23493.570951]x29:000000 7ffee581a0 x28:0000000000000000
[23493.582394]x27:0000000000000000 x26:0000000000000000
[23493.593717]x25:0000000000000000 x24:0000000000000000
[23493.604933]x23:0000000000000 27B x22:0000000000 410D85
[23493.616092]x21:0000000000000 3E8 x20:0000000000 41099C
[23493.627122]x19:00000000000000 30 x18:0000000000030a41
[23493.638002]x17:0000000000 410968 x16:000000 7FACCAE7C8
[23493.648801]x15:0000000000000809 x14:0000000000000000
[23493.659629]x13:0000000000000000 x12:0000007face1d000
[23493.670353]x11:000000000 4000000 x10:0101010101010101
[23493.681037]x9:3fffffffffffffffx8:ffffffffffffffffffffff
[23493.691716]x7:000000000 4000000 x6:0000000000000000
[23493.702436]x5:0000000000000000 x4:000000 7FFEE581F8
[23493.713174]x3:0000000000 4005B0 x2:000000 7FFEE582E8
[23493.723904]x1:000000000000000 5 x0:000000000000000 1
[23493.746914]systemd coredump[18214]：无法获取通信，返回到命令行：没有这样的进程
[23493.762810]systemd coredump[18214]：获取EXE失败，忽略：没有这样的进程

bss的大小只是没有如我第一条评论中所述的正确大小，并且得到了Notlike的加强提示：由于大小不正确，您在一段时间后碰到了MMU边界=>SEGV

使用（如中所述）：

刚刚尝试并成功（对于x86，但也应该适用于arm）：

objdump-d ascii_数组 ascii_数组_conv.o:文件格式pe-x86-64 第节的分解。正文： 0000000000000000 : ... 3e8:90无 3e9:90无 3ea:90无 3eb:90 nop 3ec:90 nop 3ed:90无 3ee:90无 3ef:90无

bss的大小只是没有如我第一条评论中所述的正确大小，并且得到了Notlike的加强提示：由于大小不正确，您在一段时间后碰到了MMU边界=>SEGV

使用（如中所述）：

刚刚尝试并成功（对于x86，但也应该适用于arm）：

objdump-d ascii_数组 ascii_数组_conv.o:文件格式pe-x86-64 第节的分解。正文： 0000000000000000 : ... 3e8:90无 3e9:90无 3ea:90无 3eb:90 nop 3ec:90 n

n_array:
    .fill 1000 , 1 , 0

>objdump -d ascii_array

ascii_array_conv.o:     file format pe-x86-64


Disassembly of section .text:

0000000000000000 <data1>:
        ...
 3e8:   90                      nop
 3e9:   90                      nop
 3ea:   90                      nop
 3eb:   90                      nop
 3ec:   90                      nop
 3ed:   90                      nop
 3ee:   90                      nop
 3ef:   90                      nop