Re: [PATCH] arm: put_user: fix possible data corruption in put_user

From: Russell King - ARM Linux
Date: Mon May 05 2014 - 05:02:48 EST


On Mon, May 05, 2014 at 10:13:58AM +0400, Andrey Ryabinin wrote:
> According to arm procedure call standart r2 register is call-cloberred.
> So after the result of x expression was put into r2 any following
> function call in p may overwrite r2. To fix this, the result of p
> expression must be saved to the temporary variable before the
> assigment x expression to __r2.

This and the patch make no sense. You talk about r2, but you're doing
nothing with r2 in the patch.

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