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Date: Fri, 30 Mar 2012 20:51:20 -0400 (EDT)
Message-Id: <20120330.205120.2221145622131588797.davem@davemloft.net>
To: drepper@gmail.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: sendmmsg: put_user vs __put_user
From: David Miller <davem@davemloft.net>
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From: Ulrich Drepper <drepper@gmail.com>
Date: Fri, 30 Mar 2012 09:36:11 -0400

> Shouldn't the compat code in the sendmmsg implementation use the same
> code as the normal code?  In which case you probably want something
> like this:

Compat processes are not able to generate virtual addresses anywhere
near the range where the kernel resides, so the address range
verification done by put_user() is completely superfluous and
therefore not necessary.  The normal exception handling done by the
access is completely sufficient.