How do I enable reverse debugging on a multi-threaded program?

Question

I'm trying to use the reverse debugging features of gdb 7.3.1 on a multi-threaded project (using libevent), but I get the following error:

(gdb) reverse-step
Target multi-thread does not support this command.

From this question, I thought perhaps that it was an issue loading libthread_db but, when I run the program, gdb says:

Starting program: /home/robb/slug/slug 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/libthread_db.so.1".

How can I enable reverse debugging with gdb 7.3.1 on a multi-threaded project? Is it possible?

Ehrenberg

There exists a link to a similar question here. – Dorolice

Yes, I know, I linked to that question in my own. – Ehrenberg

Answer 1

To do this, you need to activate the instruction-recording target, by executing the command

record

from the point where you want to go forward and backward (remember that the recording will significantly slow down the execution, especially if you have several threads!)

I've just checked that it's working correctly:

(gdb) info threads 
  Id   Target Id         Frame 
  2    Thread 0x7ffff7860700 (LWP 5503) "a.out" hello (arg=0x601030) at test2.c:16
* 1    Thread 0x7ffff7fca700 (LWP 5502) "a.out" main (argc=2, argv=0x7fffffffe2e8) at test2.c:47

...

(gdb) next
49          p[i].id=i;
(gdb) reverse-next
47      for (i=0; i<n; i++)

...

17      printf("Hello from node %d\n", p->id);
(gdb) next
Hello from node 1
18      return (NULL);
(gdb) reverse-next
17      printf("Hello from node %d\n", p->id);

Multi

When I do record I get an error: Process record target can't debug inferior in non-stop mode (non-stop). – Theriot

try set non-stop off and/or set target-async off, these options might true by default in GDB's latest versions – Multi

The record feature does not support multithreading properly. See sourceware.org/bugzilla/show_bug.cgi?id=20456#c8. – Cytoplast

The accepted answer does not work for GDB 8.0. Nor the solutions proposed by @Multi work. – Chimpanzee