Re: [discuss] [PATCH] allow CONFIG_FRAME_POINTER for x86-64

From: Hugh Dickins
Date: Fri Sep 09 2005 - 06:31:36 EST


On Fri, 9 Sep 2005, Andi Kleen wrote:
> On Fri, Sep 09, 2005 at 12:14:38PM +0100, Hugh Dickins wrote:
> >
> > Ah, right. I'm using kdb with it. (And my recollection of when
> > show_stack did have a framepointer version, is that it was hopelessly
> > broken on interrupt frames, and we're much better off without it.)
>
> Not sure if the x86-64 kdb had code to follow them either.
> The i386 one has.

x86_64 kdb does have the code to follow them, it's pretty much the same.

(kdb does have a bug in its x86_64 setjmp with framepointers, but that's
irrelevant to whether the x86_64 kernel supports framepointers.)

> But kdb should be using a dwarf2 unwinder instead. kgdb certainly
> supports that, as does NLKD.

In an ideal and bloat-neutral world. I've always imagined it to be
quite a lot of work, bringing in its own set of problems: but great
that that work has now been done, and yes, it might one day get
ported to kdb. But removing "&& !X86_64" is much easier.

Hugh
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