linux-kernel - Re: [PATCH] Ensure that walk_page_range()'s start and end are page-aligned

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Date:	Mon, 13 Feb 2012 02:12:21 -0800 (PST)
From:	David Rientjes <rientjes@...gle.com>
To:	Dan Smith <danms@...ibm.com>
cc:	akpm@...ux-foundation.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Ensure that walk_page_range()'s start and end are
 page-aligned

On Fri, 10 Feb 2012, Dan Smith wrote:

> The inner function walk_pte_range() increments "addr" by PAGE_SIZE after
> each pte is processed, and only exits the loop if the result is equal to
> "end". Current, if either (or both of) the starting or ending addresses
> passed to walk_page_range() are not page-aligned, then we will never
> satisfy that exit condition and begin calling the pte_entry handler with
> bad data.
> 
> To be sure that we will land in the right spot, this patch checks that
> both "addr" and "end" are page-aligned in walk_page_range() before starting
> the traversal.
> 

It doesn't "ensure" anything without CONFIG_DEBUG_VM enabled, which isn't 
the default.
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