Re: GDB problems

[Fuxin Zhang <fxzhang@ict.ac.cn>]

hi,
  My statements was not quit exact: the problem we met was
that when we use a > 16M local array,then the stack would be
messed up,even gdb can't reach main(). But we met it on x86,
for mips the number may be different,you can ask some mips
toolchain experts for it.

Chris Plummer wrote:

> Fuxin Zhang wrote:
>  
>
> > Chris Plummer wrote:
> >
> >    
> <snip>
>  
>
> > > (gdb) run
> > > Starting program: /usr/bin/testapp
> > > [New Thread 1024 (LWP 18281)]
> > >
> > > Program received signal SIGTRAP, Trace/breakpoint trap.
> > > [Switching to Thread 1024 (LWP 18281)]
> > > warning: Warning: GDB can't find the start of the function at 0xffffffff.
> > >      
> <snip>
>  
>
> > > 0xffffffff in ?? ()
> > > (gdb) bt
> > > #0  0xffffffff in ?? ()
> > > #1  0x2aab73c8 in _dl_init () from /lib/ld.so.1
> > > Cannot access memory at address 0x38
> > > (gdb) p $pc
> > > $1 = -1
> > > (gdb)
> > >
> > >      
> > This can happen if you have a large static/global array which can't be
> > satisfied
> >    
>
> There's definitely a lot of global data and a few large stuctures,
> including some arrays. The largest is a struct in the .bss section which
> is about 170k and includes, among other things, a 3000 element array of
> 4-word structs.
>
> Can you clarify if this is only a problem with arrays or structs also
> (and does that include arrays embedded in a struct). Also, how big is
> too big?
>
> Can you also explain what "can't be satisfied" means. Is this mememory
> related? I have a 192mb RAM + 256mb swap in this Indy. Is there anything
> I can do to work around this problem, other than making some of the
> arrays/structs smaller.
>
> I should also add that gdb doesn't have a problem with this app on other
> platforms (linux-arm, linux-ppc, linux-x86), although none of these
> other platforms is running Debian.
>
> Chris
>
>
>