Re: i386 int3 handling, running vs stepping

Doug Evans
2009-02-01T23:38:16Z

On Sun, Feb 1, 2009 at 3:32 PM, Daniel Jacobowitz <drow@false.org> wrote:
> On Sun, Feb 01, 2009 at 03:18:19PM -0800, Doug Evans wrote:
>
>> Trying things again, this time stepi'ing over the insn:
>>
>> bash$ gdb int3
>> (gdb) start
>> [...]
>> Temporary breakpoint 1, main () at int3.S:4
>> 4 nop
>> Current language: auto; currently asm
>> (gdb) si
>> 5 int3
>> (gdb) si
>> 6 nop
>> (gdb)
>>
>> Note that int3 was stepping over without a SIGTRAP being generated.
>
> I can't see a plausible way around this, can you? The SIGTRAP is
> identical to the one for PTRACE_SINGLESTEP - unless the kernel
> annotates the siginfo differently?

I haven't looked into siginfo, but can gdb look at the insn? [akin to
displaced stepping handling]