Re: remote connection crash, was frame theory

Daniel Jacobowitz
2006-01-26T23:45:06Z

On Thu, Jan 26, 2006 at 03:42:02PM -0800, Jim Blandy wrote:
> On 1/26/06, NZG <ngustavson@emacinc.com> wrote:
> > On Thursday 26 January 2006 4:44 pm, Daniel Jacobowitz wrote:
> > > On Thu, Jan 26, 2006 at 11:40:07PM +0100, Mark Kettenis wrote:
> > > > To me, it looks like you're connecting to a buggy stub.
> > >
> > > He's connecting to basically a standard gdbserver, poised at
> > > the first instruction of the program. Memory has garbage
> > > and/or is invalid - no MMU so reading from garbage memory
> > > is a bit more serious than is typical for GDB.
> > righto, it crashes the remote kernel and sends my host into an infinite loop
> > in gdb.
> >
> > > The best thing here would be, if the stub can find out from
> > > the kernel what constitutes "valid" RAM, to refuse reads to
> > > it. Then ignore the ugliness when you type backtrace and
> > > don't have a stack yet - it's not real surprising that doesn't
> > > work!
>
> The PC is valid at this point, right? If there were clean Dwarf CFI
> for the entry point, marking it as the oldest frame, would that calm
> GDB down? That could be another approach.

Yes, that should generally work.

--
Daniel Jacobowitz
CodeSourcery