Messages in this thread | | | Subject | Re: [PATCH] Ensure that walk_page_range()'s start and end are page-aligned | Date | Fri, 10 Feb 2012 20:45:12 +0100 | From | "Michal Nazarewicz" <> |
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On Fri, 10 Feb 2012 20:39:56 +0100, Dan Smith <danms@us.ibm.com> wrote: > The inner function walk_pte_range() increments "addr" by PAGE_SIZE after
Commit message says about walk_pte_range() but commit changes walk_page_range().
> 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
So why not change the condition to addr < end?
> 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. > > Signed-off-by: Dan Smith <danms@us.ibm.com> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > mm/pagewalk.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/mm/pagewalk.c b/mm/pagewalk.c > index 2f5cf10..9242bfc 100644 > --- a/mm/pagewalk.c > +++ b/mm/pagewalk.c > @@ -196,6 +196,8 @@ int walk_page_range(unsigned long addr, unsigned long end, > if (addr >= end) > return err; >+ VM_BUG_ON((addr & ~PAGE_MASK) || (end & ~PAGE_MASK)); > + > if (!walk->mm) > return -EINVAL; >
-- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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