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From: David Hinds <dhinds@sonic.net>
To: J?rn Engel <joern@wohnheim.fh-wedel.de>, linux-kernel@vger.kernel.org
Subject: Re: Worst recursion in the kernel
Date: Wed, 3 Dec 2003 15:36:01 -0800	[thread overview]
Message-ID: <20031203153601.A23640@sonic.net> (raw)
In-Reply-To: <20031203230832.GD29119@mis-mike-wstn.matchmail.com>

On Wed, Dec 03, 2003 at 03:08:32PM -0800, Mike Fedyk wrote:
> On Wed, Dec 03, 2003 at 10:57:43PM +0000, Russell King wrote:
> > Yes, but the condition of the /data/ is such that it will not recurse.
> > 
> > A pure "can this function call that function" analysis ignoring the
> > state of the data will say this will infinitely recuse.  Include
> > the data, and you'll find it has a very definite recursion limit.
> 
> Is the data verified?

Russell is using "data" loosely.  Basically the logic goes like this:

read_cis_mem():
  if sys_start is NULL then call validate_mem()

validate_mem():
  set sys_start
  call stuff that calls read_cis_mem()

so the functions do not require consistency of any external program
data to avoid recursion.

-- Dave


  reply	other threads:[~2003-12-03 23:36 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-12-03 14:31 Worst recursion in the kernel Jörn Engel
2003-12-03 18:07 ` David Hinds
2003-12-03 19:04   ` Jörn Engel
2003-12-03 22:57     ` Russell King
2003-12-03 23:08       ` Mike Fedyk
2003-12-03 23:36         ` David Hinds [this message]
2003-12-04 14:14       ` Jörn Engel
2003-12-04 15:08       ` Martin Waitz
2003-12-04 18:40         ` Russell King
2003-12-04 18:46           ` Jörn Engel
2003-12-03 23:08     ` David Hinds
2003-12-04 13:47       ` Jörn Engel

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