Subject: Re: [PATCH] tun

From: "David S. Miller" <[email-masked]>
Date: Mon, 15 Mar 2004 12:47:51 -0800

On Mon, 15 Mar 2004 10:28:10 -0800
Stephen Hemminger <[email-masked]> wrote:

> Tun verifies the user address before doing memcpy_from/toiovec.  There are
> two problems with this strategy.  First, it is possible on an SMP machine
> to construct cases where a page is unmmapped between the verify and the copy,
> and it is also faster to do the verification only once.

Yes, those verify_area calls are superfluous and racy.

Applied, thanks Stephen.