Re: [PATCH] Ensure that walk_page_range()'s start and end arepage-aligned

From: David Rientjes
Date: Mon Feb 13 2012 - 05:12:29 EST


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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