On Thursday 24 January 2008 04:05, Linus Torvalds wrote:
quoted text
> On Wed, 23 Jan 2008, Anton Salikhmetov wrote:
> > +
> > +		if (pte_dirty(*pte) && pte_write(*pte)) {
>
> Not correct.
>
> You still need to check "pte_present()" before you can test any other
> bits. For a non-present pte, none of the other bits are defined, and for
> all we know there might be architectures out there that require them to
> be non-dirty.
>
> As it is, you just possibly randomly corrupted the pte.
>
> Yeah, on all architectures I know of, it the pte is clear, neither of
> those tests will trigger, so it just happens to work, but it's still
> wrong.

Probably it can fail for !present nonlinear mappings on many
architectures.

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