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Re: [PATCH 7/7] Allow unwind_stack() to return ra for leaf function

To: "Atsushi Nemoto" <anemo@mba.ocn.ne.jp>
Subject: Re: [PATCH 7/7] Allow unwind_stack() to return ra for leaf function
From: "Franck Bui-Huu" <vagabon.xyz@gmail.com>
Date: Tue, 1 Aug 2006 21:38:18 +0200
Cc: ralf@linux-mips.org, linux-mips@linux-mips.org
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2006/8/1, Atsushi Nemoto <anemo@mba.ocn.ne.jp>:
On Tue,  1 Aug 2006 11:27:17 +0200, Franck Bui-Huu <vagabon.xyz@gmail.com> 
wrote:
> Since get_frame_info() is more robust, unwind_stack() can
> returns ra value for leaf functions.

I think it is still fragile.  The get_frame_info() might misdetect
nested function as leaf.  For example, I can craft this code:


Considering (wrongly) a nested function as a leaf one is not a big
issue. "ra" reg should _always_ store a valid address (nested or not).
The only (small) impact would be to skip an entry when showing the
backtrace.

--
              Franck

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