problem unwinding past pthread_cond_wait() on x86 RedHat 9.0
Daniel Jacobowitz
drow@mvista.com
Tue Oct 14 16:18:00 GMT 2003
On Tue, Oct 14, 2003 at 12:15:53PM -0400, Andrew Cagney wrote:
> >On Tue, Oct 14, 2003 at 08:46:49AM -0700, Joel Brobecker wrote:
> >
> >>> Joel, what happens if you type:
> >>>
> >>> (gdb) x/i 0xffffe002
> >
> >>
> >>Something like "Cannot read memory at 0xffffe002" (already tried it :-).
> >>What is this address, BTW. I always wondered... Kernel code? Special
> >>address?
> >
> >
> >Search for "vsyscall DSO" in the gdb@ archives to learn more than you
> >ever wanted to know :) Patches to fully support it are still pending.
>
> No.
>
> No matter how much you patch GDB, GDB isn't going to dig itself out of
> thishole. It's not able to access the code/data/whatever at that
> address so it's never going to correctly unwind from it.
>
> Kernel bug - incomplete functionality.
We're both right. Patches for this are still pending. They'll fix the
unwinding when using a 2.6 kernel which _does_ let the page be
accessed. At that point I wouldn't be surprised if you folks at RH
published an errata kernel which let this work in RH9, or RH10 or
whatever it is now.
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
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