Re: problem with exec-file when targetting remote machine

[Daniel Jacobowitz <drow@mvista.com>]

On Mon, Mar 24, 2003 at 03:07:43PM -0500, Kris Warkentin wrote:
> This problem comes up when using the QNX remote protocol but it's probably
> more generic than that.  I'm not asking for a fix but more for some guidance
> as to what might be happening.
> 
> The long and short of it is that if I attach to a process on a remote
> machine after having read the symbols, everything works fine.  I run gdb,
> load symbols, set a breakpoint on main, run and get:
> 
> Breakpoint 1, main (argc=1, argv=0x803fcc4) at NetController.cpp:62
> 62         int   lSuccessCode = 0;   // Success
> 
> as one might expect.  If, however, exec-file has been set, either explicitly
> or implicitly by calling "gdb myapp" from the command line, I get something
> like:
> 
> Breakpoint 1, 0x40380000 in ?? ()
> (gdb) bt
> #0  0x40380000 in ?? ()
> #1  0x00000001 in ?? ()
> 
> Note that this doesn't happen with everything - it seems to be mostly with
> large projects, particularily C++.  There's obviously some data being read
> by gdb based on what the exec-file is set as that is causing a problem.
> 
> Can anyone give me an idea as to what gdb might be doing differently when
> exec-file has been set?

This means shared library handling is messed up, I bet.  It only
triggers based on exec_bfd.

Probably the app is being relocated in memory by the shared library
code, and ending up wrong.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer