Re: [PATCH 05/10] mm, util: Use dup_user to duplicate user memory

[Andrew Morton]

On Sat,  8 Sep 2012 17:47:54 -0300
Ezequiel Garcia <elezegarcia@xxxxxxxxx> wrote:

> Previously the strndup_user allocation was being done through memdup_user,
> and the caller was wrongly traced as being strndup_user
> (the correct trace must report the caller of strndup_user).
> 
> This is a common problem: in order to get accurate callsite tracing,
> a utils function can't allocate through another utils function,
> but instead do the allocation himself (or inlined).
> 
> Here we fix this by creating an always inlined dup_user() function to
> performed the real allocation and to be used by memdup_user and strndup_user.

This patch increases util.o's text size by 238 bytes.  A larger kernel
with a worsened cache footprint.

And we did this to get marginally improved tracing output?  This sounds
like a bad tradeoff to me.

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