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Date: Tue, 10 Apr 2001 06:41:28 -0400
From: Jakub Jelinek <jakub@redhat.com>
To: Dawson Engler <engler@csl.Stanford.EDU>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [CHECKER] amusing copy_from_user bug
Message-ID: <20010410064128.C1169@devserv.devel.redhat.com>
Reply-To: Jakub Jelinek <jakub@redhat.com>
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In-Reply-To: <200104101011.DAA29579@csl.Stanford.EDU>; from engler@csl.Stanford.EDU on Tue, Apr 10, 2001 at 03:11:05AM -0700
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On Tue, Apr 10, 2001 at 03:11:05AM -0700, Dawson Engler wrote:
> As a side question: is it still true that verify_area's must be done before
> any use of __put_user/__get_user/__copy_from_user/etc?

I believe so, at least in generic code.
In architecture specific code (non-i386) it is usually sufficient just to do
one put_user/get_user/copy_from_user and then do the rest of
__put_user/__get_user etc. from nearby area (<4K is safe e.g. on sparc) and
some architectures don't care at all, because verify_area is a noop
(sparc64).

	Jakub
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