程序可以在调试器外部调试程序中运行，SIGILL在调试程序中时是否正在执行？

Question

我试图在BeagleBone Black上调试一个程序。在调试器外部，它会产生不正确的结果，但不会产生SIGILL。它也可以在没有断点的调试器下运行。然而，它产生一个SIGILL与步进时设置的断点。程序和库不使用基于SIGILL的cpu功能探测器。但是，我不知道GDB在做什么。

在调试器我看到：

(gdb) b main 
Breakpoint 1 at 0x26f20: file test.cxx, line 22. 
(gdb) r 
Starting program: /home/cryptopp/test.exe 

Breakpoint 1, main (argc=0x1, argv=0xbeffea54) at test.cxx:22 
22   byte key[16] = {0}; 
(gdb) n 
23   byte iv[12] = {0}; 
(gdb) 
25   GCM<AES>::Encryption enc; 
(gdb) 
26   enc.SetKeyWithIV(key, 16, iv, 12); 
(gdb) 
28   std::string plain(0x00, 16); 
(gdb) 

Program received signal SIGILL, Illegal instruction. 
0x00026d5c in std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&) 
    () 
(gdb) n 
Single stepping until exit from function _ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_, 
which has no line number information. 

Program terminated with signal SIGILL, Illegal instruction. 
The program no longer exists. 

和：

(gdb) shell echo _ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_ | c++filt 
std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&) 

我试图寻找这个问题，但我一直没能找到一个打击。我得到太多的噪音。

为什么我在GDB设置断点时遇到SIGILL，我该如何解决它？

---

NEON是我正在调查的问题。下面是用于程序和库中的命令行：

$ echo $CXXFLAGS 
-DDEBUG -g3 -O0 -march=armv7-a -mtune=cortex-a8 -mfpu=neon -mfloat-abi=hard 
$ g++ $CXXFLAGS test.cxx ./libcryptopp.a -o test.exe 

和：

$ gdb --version 
GNU gdb (Debian 7.7.1+dfsg-5) 7.7.1 

$ uname -a 
Linux beaglebone 4.1.15-ti-rt-r40 #1 SMP PREEMPT RT Thu Jan 7 23:32:08 UTC 2016 armv7l GNU/Linux 

$ cat /proc/cpuinfo 
processor  : 0 
model name  : ARMv7 Processor rev 2 (v7l) 
BogoMIPS  : 996.14 
Features  : half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpd32 
CPU implementer : 0x41 
CPU architecture: 7 
CPU variant  : 0x3 
CPU part  : 0xc08 
CPU revision : 2 

Hardware  : Generic AM33XX (Flattened Device Tree) 
Revision  : 0000 
Serial   : 0000000000000000 

和：

Breakpoint 1, main (argc=0x1, argv=0xbeffea54) at test.cxx:22 
22   byte key[16] = {0}; 
(gdb) n 
23   byte iv[12] = {0}; 
(gdb) 
25   GCM<AES>::Encryption enc; 
(gdb) 
26   enc.SetKeyWithIV(key, 16, iv, 12); 
(gdb) 
28   std::string plain(0x00, 16); 
(gdb) 

Program received signal SIGILL, Illegal instruction. 
0x00026d5c in std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&) 
    () 

(gdb) up 
#1 0x00026f82 in main (argc=0x1, argv=0xbeffea54) at test.cxx:28 
28   std::string plain(0x00, 16); 
(gdb) disass 
Dump of assembler code for function main(int, char**): 
    0x00026f10 <+0>:  push {r4, r7, lr} 
    0x00026f12 <+2>:  sub.w sp, sp, #916 ; 0x394 
    0x00026f16 <+6>:  add  r7, sp, #16 
    0x00026f18 <+8>:  adds r3, r7, #4 
    0x00026f1a <+10>: str  r0, [r3, #0] 
    0x00026f1c <+12>: mov  r3, r7 
    0x00026f1e <+14>: str  r1, [r3, #0] 
    0x00026f20 <+16>: add.w r3, r7, #692 ; 0x2b4 
    0x00026f24 <+20>: movs r2, #0 
    0x00026f26 <+22>: str  r2, [r3, #0] 
    0x00026f28 <+24>: adds r3, #4 
    0x00026f2a <+26>: movs r2, #0 
    0x00026f2c <+28>: str  r2, [r3, #0] 
    0x00026f2e <+30>: adds r3, #4 
    0x00026f30 <+32>: movs r2, #0 
    0x00026f32 <+34>: str  r2, [r3, #0] 
    0x00026f34 <+36>: adds r3, #4 
    0x00026f36 <+38>: movs r2, #0 
    0x00026f38 <+40>: str  r2, [r3, #0] 
    0x00026f3a <+42>: adds r3, #4 
    0x00026f3c <+44>: add.w r3, r7, #680 ; 0x2a8 
    0x00026f40 <+48>: movs r2, #0 
---Type <return> to continue, or q <return> to quit--- 
    0x00026f42 <+50>: str  r2, [r3, #0] 
    0x00026f44 <+52>: adds r3, #4 
    0x00026f46 <+54>: movs r2, #0 
    0x00026f48 <+56>: str  r2, [r3, #0] 
    0x00026f4a <+58>: adds r3, #4 
    0x00026f4c <+60>: movs r2, #0 
    0x00026f4e <+62>: str  r2, [r3, #0] 
    0x00026f50 <+64>: adds r3, #4 
    0x00026f52 <+66>: add.w r3, r7, #240 ; 0xf0 
    0x00026f56 <+70>: mov  r0, r3 
    0x00026f58 <+72>: bl  0x2a804 <CryptoPP::GCM_Final<CryptoPP::Rijndael, (CryptoPP::GCM_TablesOption)0, true>::GCM_Final()> 
    0x00026f5c <+76>: add.w r1, r7, #240 ; 0xf0 
    0x00026f60 <+80>: add.w r2, r7, #692 ; 0x2b4 
    0x00026f64 <+84>: add.w r4, r7, #680 ; 0x2a8 
    0x00026f68 <+88>: movs r3, #12 
    0x00026f6a <+90>: str  r3, [sp, #0] 
    0x00026f6c <+92>: mov  r0, r1 
    0x00026f6e <+94>: mov  r1, r2 
    0x00026f70 <+96>: movs r2, #16 
    0x00026f72 <+98>: mov  r3, r4 
    0x00026f74 <+100>: bl  0x2da0c <CryptoPP::SimpleKeyingInterface::SetKeyWithIV(unsigned char const*, unsigned int, unsigned char const*, unsigned int)> 
---Type <return> to continue, or q <return> to quit--- 
    0x00026f78 <+104>: add.w r3, r7, #708 ; 0x2c4 
    0x00026f7c <+108>: mov  r0, r3 
    0x00026f7e <+110>: blx  0x26d58 <_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_+852> 
=> 0x00026f82 <+114>: add.w r2, r7, #676 ; 0x2a4 
    0x00026f86 <+118>: add.w r3, r7, #708 ; 0x2c4 
    0x00026f8a <+122>: mov  r0, r2 
    0x00026f8c <+124>: movs r1, #0 
    0x00026f8e <+126>: movs r2, #16 
    ... 

Answer 1

感谢@ ks1322，这是一个已知的GDB /内核错误。请参阅GDB问题跟踪器中的GDB crashes on debugging multithreaded program on ARM SMP dual core system。

根据Debian BTS的说法，这也是一个已知的问题。请参阅Debian BTS中的SIGILL when stepping through application on armhf。

该错误被重新填充，希望它可能实际上在未来一两年的某个时间被修复。请参阅GDB Crash due to GDB/Kernel generated SIGILL

这就是为什么我鄙视Debian的错误报告系统的原因。东西得到报道，然后它就会腐烂。没有什么固定的。