Date: Fri, 9 Sep 2005 12:14:38 +0100 (BST)
From: Hugh Dickins <hugh@veritas.com>
To: Andi Kleen <ak@suse.de>
cc: Jan Beulich <JBeulich@novell.com>, linux-kernel@vger.kernel.org,
       discuss@x86-64.org
Subject: Re: [discuss] [PATCH] allow CONFIG_FRAME_POINTER for x86-64
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On Fri, 9 Sep 2005, Andi Kleen wrote:
> 
> It won't give more accurate backtraces, not even on i386 because show_stack
> doesn't have any code to follow frame pointers.

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.)

> The only reason to use them would be external debuggers, but those
> don't need them on x86-64 neither.

Don't need them, but find them as useful on x86_64 as on i386?

Certainly, I can go on patching in FRAME_POINTERs for x86_64
as I have done, no problem with that.  But it seems both bogus
and unhelpful to have that "&& !X86_64" in lib/Kconfig.debug -
framepointers are as helpful/useless on x86_64 as the rest.

Hugh
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