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

[Andrea Arcangeli]

On Tue, May 25, 2004 at 07:26:21PM -0700, Linus Torvalds wrote:
> You're reading it wrong.
> 
> The "including when the present flag is set to zero" part does not mean 
> that the present flag was zero _before_, it means "is being set to zero" 
> as in "having been non-zero before that".

"having been non-zero before that" makes a lot more sense indeed, the
wording in the specs wasn't the best IMHO.  Interestingly the
ptep_establish at the end of handle_pte_fault would have hidden any
double fault completely, nobody but a tracer would have noticed that,
but it made very little sense that non-present entries can be cached.
It's all clear now thanks.
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