Re: RFC: %ebp-based backtrace patch

Michael Matz
2009-07-07T13:49:02Z

Hi,

On Tue, 7 Jul 2009, Frank Ch. Eigler wrote:

> On Tue, Jul 07, 2009 at 02:15:19PM +0200, Michael Matz wrote:
> > [...]
> > > Could gdb partially disassemble such functions to check
> > > whether %ebp is likely being used as this heuristic expects?
> >
> > Nope. We don't know the function borders. [...]
>
> I'm feeling dense, so can you explain why? We have at least a
> PC value, which one could map in the symbol table, no?

There is no complete symbol table anymore, only the exported symbol table
which is empty for executable by default and doesn't contain e.g. static
functions for shared libs. That's the whole point. We are talking about
stripped objects for which we still want to generate useful backtraces (or
at least not disturb backtracing when even just one shared lib in the call
stack was stripped) so that bugreports of crashes are not completely
useless and misleading.

Ciao,
Michael.