BDI2000 "Cannot insert breakpoint"

[frank.theinen@lancom.de]

Hi Shaun,

> I am using a BDI2000 over Ethernet with gdb 6.3.50.20050801-cvs for
> arm-elf. Occasionally, if I have a breakpoint set a continue or next
> command will fail with an "Error accessing memory address" error as
> below:
> 
> (gdb) n
> Warning:
> Cannot insert breakpoint 0.
> Error accessing memory address 0x2017fe0: Unknown error 4294967295.
> 
> Often clearing the breakpoints with 'd b' and resetting the breakpoint
> will fix things. Is this perhaps related to hardware/software
> breakpoints? Any idea why it's failing?

yes, probably. If you configured the BDI2000 to use hardware breakpoints, 
and you have two breakpoints set, this will happen, when GDB "nexts" a 
subroutine call. GDB usually does single stepping, and when it 
single-steps into a subroutine, it sets a (kind of) temporary breakpoint 
at the position the LR points to and "continues" to leave the subroutine.

You can verify this behaviour by capturing the serial GDB communication 
where you can see the failing breakpoint setting operation.

Regards, Frank