Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE

[Benjamin Herrenschmidt]

On Mon, 2004-05-24 at 15:38, Benjamin Herrenschmidt wrote:
> > Well, the original scenario triggering that from userland is, imho, so
> > broken, that we may just not care losing that dirty bit ... Oh well :)
> > Anyway, apply my patch. If pte is not present, this will have no effect,
> > if it is, it makes sure we never leave a stale HPTE in the hash, which
> > is fatal in far worse ways.
> 
> Hrm... Or maybe I should just do in set_pte something like
> 
>  BUG_ON(pte_present(ptep))
> 
> That would make me sleep better ;)

 ... And would not work in the case you mentioned where we set it with
the dirty bit set... for write protect, we have a separate function now,
though. But I'm a bit paranoid with those PTE manipulations, so I think
it would be better to play it the safe way and keep my original patch.

Ben.


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