I was tring to use "reverse-step" and "reverse-next" command inside gdb. Stack overflow tells me that I should run "target record-full" in the execution context where I wish to "rn" and "rs". But some weird error happened:
1
2 #include<stdio.h>
3 int i=0;
4 void fa()
5 {
6 ++i;
7 printf("%d\n",i);
8 ++i;
9 }
10 int main(){
11 fa();
12 return 0;
13 }
I compile and run this program:
(gdb) b 4
Breakpoint 1 at 0x40052a: file test02.c, line 4.
(gdb) r
Starting program: /home/Troskyvs/a.out
Breakpoint 1, fa () at test02.c:6
6 ++i;
(gdb) target record-full
(gdb) n
7 printf("%d\n",i);
(gdb) n # Error happens here!
Process record does not support instruction 0xc5 at address 0x7ffff7dee6e7.
Process record: failed to record execution log.
Program stopped.
_dl_runtime_resolve_avx () at ../sysdeps/x86_64/dl-trampoline.h:81
81 ../sysdeps/x86_64/dl-trampoline.h: No such file or directory.
Well if I don't run "target record-full", then the 2nd "n" will be OK and run to next line. I don't quite get the error information here.
Is it related to "target record-full"? How can I conquor it?
I tried another approach:
(gdb) set exec-direction reverse
(gdb) n
No more reverse-execution history.
fa () at test02.c:7
7 printf("%d\n",i);
(gdb) n
No more reverse-execution history.
fa () at test02.c:7
7 printf("%d\n",i);
(gdb) n
Well, it doesn't work
AVX is not supported as of GDB 7.11.1
The underlying problem seems to be that AVX instructions are not currently supported, but glibc uses them on Ubuntu 16.04 64-bit:
rr is an awesome working alternative: https://github.com/mozilla/rr Here is a minimal working example: Setting breakpoint in GDB where the function returns