Re: [patch] mm: sparsemem memory_present() memory corruption fix

From: Yinghai Lu
Date: Tue Apr 15 2008 - 21:31:11 EST


On Tue, Apr 15, 2008 at 6:17 PM, Ingo Molnar <mingo@xxxxxxx> wrote:
>
> * Ingo Molnar <mingo@xxxxxxx> wrote:
>
> > > > this is the only call to memory_present() we do in 32-bit arch
> > > > setup, so it's required.
> > >
> > > We could clip there if SPARSEMEM is configured. I wonder if this
> > > affects other platforms that need HIGHMEM support?
> >
> > clip where and what?
>
> i.e. as per my previous argument i'd consider the need to sanitize the
> calls in the architecture fundamentally wrong.
>
> whether the core code emits a warning or allows the call is an
> additional question i mention in the changelog - but the core sparse
> memory code should _definitely_ not silently overflow a key internal
> array ... (of which data structure the architecture code is not even
> aware of)

or you can move that check into find_max_pfn for x86_32? so it will
not affect other platform regarding Christoph's concern?

YH
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