Re: [rfc][patch] mm: dirty page accounting race fix

Jeremy Fitzhardinge
2008-08-14T20:25:20Z

Hugh Dickins wrote:
> I realized that was the intended optimization, what I'd missed is that
> dirty_accountable can only be true there if (vma->vm_flags & VM_WRITE):
> that's checked in vma_wants_writenotify(), which is how dirty_accountable
> gets to be set.
>
> So those lines are okay, panic over, phew.
>

I got bitten by precisely the same train of thought. I think that code
officially Non Obvious (or at least Not Immediately Obvious, which is
bad in security-sensitive code).

J