Re: [Linux-ia64] Unwind can load wrong data from pt_regs

David Mosberger
2002-12-09T21:21:07Z

>>>>> On Mon, 09 Dec 2002 19:35:03 +1100, Keith Owens <kaos@sgi.com> said:

Keith> This implicitly assumes that when a fr or br register is
Keith> required from pt_regs, info->sp is pointing to pt_regs. But
Keith> info->sp is modified as the code unwinds through each
Keith> function. The above code only gives correct results for
Keith> register lookups from the failing function. Unwinding and
Keith> accessing a fr or br register from earlier functions loads
Keith> incorrect values for those registers.

Yes, this is something that has been fixed already in the user-level
libunwind. It's not hard to fix, just someone needs to get around to
do it. I don't think it's a critical issue, since it only happens for
nested traps. I assume you saw this with kdb?

--david