From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:51395 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730862AbfACObU (ORCPT ); Thu, 3 Jan 2019 09:31:20 -0500 Date: Thu, 3 Jan 2019 09:31:16 -0500 From: Jerome Glisse Subject: Re: [PATCH] Initialise mmu_notifier_range correctly Message-ID: <20190103143116.GB3395@redhat.com> References: <20190103002126.GM6310@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190103002126.GM6310@bombadil.infradead.org> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Matthew Wilcox Cc: Andrew Morton , linux-mm@kvack.org, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, Christian =?iso-8859-1?Q?K=F6nig?= , Jan Kara On Wed, Jan 02, 2019 at 04:21:26PM -0800, Matthew Wilcox wrote: > > One of the paths in follow_pte_pmd() initialised the mmu_notifier_range > incorrectly. > > Signed-off-by: Matthew Wilcox > Fixes: ac46d4f3c432 ("mm/mmu_notifier: use structure for invalidate_range_start/end calls v2") > Tested-by: Dave Chinner Actually now that i have read the code again this is not ok to do so. The caller of follow_pte_pmd() will call range_init and follow pmd will only update the range address. So existing code is ok. I know this is kind of ugly but i do not see a way around that uglyness. > > diff --git a/mm/memory.c b/mm/memory.c > index 2dd2f9ab57f4..21a650368be0 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4078,8 +4078,8 @@ static int __follow_pte_pmd(struct mm_struct *mm, unsigned long address, > goto out; > > if (range) { > - range->start = address & PAGE_MASK; > - range->end = range->start + PAGE_SIZE; > + mmu_notifier_range_init(range, mm, address & PAGE_MASK, > + (address & PAGE_MASK) + PAGE_SIZE); > mmu_notifier_invalidate_range_start(range); > } > ptep = pte_offset_map_lock(mm, pmd, address, ptlp);