set breakpoints in remote debugging

set breakpoints in remote debugging

[fzchuan]

Hi all:

I encountered some problems in GDB remote debugging.
In most of time, GDB host would send correct breakpoint address to target which 
I asked it. But sometimes it would send strange address.
That is,in GDB host side,I set breakpoint on some address,i.e.:
(gdb)b *0x8

Then, in target side, target will receive the request. 
I print the message received from GDB host,
and it shows that GDB ask target to stop at 0xc6

I use GDB disassemble to query 0x8, and is shows that it is a Call (JUMP)
instruction and jump target address is 0xc6.

Why? thanks

Pin-Chuan

Re: set breakpoints in remote debugging

[Daniel Jacobowitz]

On Thu, Nov 03, 2005 at 01:34:48AM +0800, fzchuan wrote:
> 
> Hi all:
> 
> I encountered some problems in GDB remote debugging.
> In most of time, GDB host would send correct breakpoint address to target which 
> I asked it. But sometimes it would send strange address.
> That is,in GDB host side,I set breakpoint on some address,i.e.:
> (gdb)b *0x8
> 
> Then, in target side, target will receive the request. 
> I print the message received from GDB host,
> and it shows that GDB ask target to stop at 0xc6
> 
> I use GDB disassemble to query 0x8, and is shows that it is a Call (JUMP)
> instruction and jump target address is 0xc6.
> 
> Why? thanks

There is not enough information to answer your question.  When does
this happen?  What does the remote protocol and GDB console show when
it does?  What target is this?

-- 
Daniel Jacobowitz
CodeSourcery, LLC

Re: set breakpoints in remote debugging

[Paul Koning]

>>>>> "fzchuan" == fzchuan  <fzchuan@eos.cs.nthu.edu.tw> writes:

 fzchuan> Hi all:

 fzchuan> I encountered some problems in GDB remote debugging.  In
 fzchuan> most of time, GDB host would send correct breakpoint address
 fzchuan> to target which I asked it. But sometimes it would send
 fzchuan> strange address.  That is,in GDB host side,I set breakpoint
 fzchuan> on some address,i.e.: (gdb)b *0x8

 fzchuan> Then, in target side, target will receive the request. I
 fzchuan> print the message received from GDB host, and it shows that
 fzchuan> GDB ask target to stop at 0xc6

 fzchuan> I use GDB disassemble to query 0x8, and is shows that it is
 fzchuan> a Call (JUMP) instruction and jump target address is 0xc6.

 fzchuan> Why? thanks

You probably did a step command.  Step is usually done by setting a
breakpoint at the address after the instruction.  For jumps, that
"next" address is the target address.

       paul