Re: Can get_user_pages( ,write=1, force=1, ) result in a read-only pte and _count=2?

[Robin Holt <holt@sgi.com>]

On Thu, Jun 19, 2008 at 02:25:10PM +0100, Hugh Dickins wrote:
> On Thu, 19 Jun 2008, Nick Piggin wrote:
> > On Thursday 19 June 2008 22:34, Hugh Dickins wrote:

> > Oh, I missed that. You're now thinking they do have VM_WRITE on
> > the vma and hence your patch isn't going to work (and neither
> > force=0). OK, that sounds right to me.
> 
> I'm still confused.  I thought all along that they have VM_WRITE on
> the vma, which Robin has (by implication) confirmed when he says that
> userspace is trying to write to the same page - I don't think he'd
> expect it to be able to do so without VM_WRITE.

It does have VM_WRITE set.  I do expect this patch to at least change
the problem.  I am also working on testing (seperately) with force=0 to
verify that does not introduce other regressions.  I am doing this
testing against a sles10 kernel and not Linus' latest and greatest.  I
will try to test Linus' kernel later, but that will take more time.

Thanks,
Robin

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