From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 19 Jun 2008 08:35:50 -0500 From: Robin Holt Subject: Re: Can get_user_pages( ,write=1, force=1, ) result in a read-only pte and _count=2? Message-ID: <20080619133550.GB10123@sgi.com> References: <20080618164158.GC10062@sgi.com> <200806192207.40838.nickpiggin@yahoo.com.au> <200806192253.16880.nickpiggin@yahoo.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Hugh Dickins Cc: Nick Piggin , Robin Holt , Ingo Molnar , Christoph Lameter , Jack Steiner , linux-mm@kvack.org List-ID: 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org