Date: Wed, 3 May 2006 09:08:11 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Keith Owens <kaos@sgi.com>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org
Subject: Re: [patch, 2.6.17-rc3-mm1] i386: break out of recursion in stackframe walk
Message-ID: <20060503070811.GC23921@elte.hu>
References: <20060502095034.GA21063@elte.hu> <16113.1146632636@kao2.melbourne.sgi.com>
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* Keith Owens <kaos@sgi.com> wrote:

> KDB just limits kernel traces to a maximum of 200 entries, which 
> catches direct as well as indirect recursion.  IA64 is notorious for 
> getting loops in its unwind data, sometime looping over three or four 
> functions.  Checking for a maximum number of entries is a simple and 
> architecture independent check.

you are right, but in this particular case this doesnt seem to be 
'wrong' unwind data, it's more of a special marker of the end of the 
frame (if i understood it correctly). If it's wrong unwind data then 
that data should be fixed.

I also agree with adding a limit to catch buggy cases of recursion, as a 
separate mechanism, independently of this particular bug.

	Ingo
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