From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B727C43387 for ; Thu, 3 Jan 2019 14:43:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 192A32070D for ; Thu, 3 Jan 2019 14:43:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="eP8Ighkg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732009AbfACOnR (ORCPT ); Thu, 3 Jan 2019 09:43:17 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:54742 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727436AbfACOnQ (ORCPT ); Thu, 3 Jan 2019 09:43:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=YwpJbb3OcnPjGYvo3jjt8nSUTMJBu8TN1h47nuDYqwE=; b=eP8Ighkgi/CSBdP7uYdeWJrxA 3kNThYO+QN02kUrh0HLyJS3gW7by6AUX6+WsMSSJ949FOSYzxJXZUG8/6VjmlstjOWgWmmnz1Cu65 ci5pSsGZ0Pr5tEsL1oH/2h5n7Ljd07YJrnzkqTLoQZkg5d34JfJEDkB74V3Isq47u24XrxAAhggah +i3jEQPC0Nb2eI0k/QOY9xKZnuNa4F85/tUiltOhePktxG3N7EnEk4eypiXlJczSVBHd3dUn9tuIJ o+ZdDWGJPmPu/jstEdJBdyLC+xK/sappsJ8iBTYu0rEJUMatO91Tpl+Hw4rn3RooTMufRGa/EjrLg HNnQdwEHQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gf4DJ-00036V-EI; Thu, 03 Jan 2019 14:43:13 +0000 Date: Thu, 3 Jan 2019 06:43:13 -0800 From: Matthew Wilcox To: Jerome Glisse 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 Subject: Re: [PATCH] Initialise mmu_notifier_range correctly Message-ID: <20190103144313.GR6310@bombadil.infradead.org> References: <20190103002126.GM6310@bombadil.infradead.org> <20190103143116.GB3395@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190103143116.GB3395@redhat.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 03, 2019 at 09:31:16AM -0500, Jerome Glisse wrote: > 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 think you need to re-read your own patch. `git show ac46d4f3c43241ffa23d5bf36153a0830c0e02cc` @@ -4058,10 +4059,10 @@ static int __follow_pte_pmd(struct mm_struct *mm, unsigned long address, if (!pmdpp) goto out; - if (start && end) { - *start = address & PMD_MASK; - *end = *start + PMD_SIZE; - mmu_notifier_invalidate_range_start(mm, *start, *end); + if (range) { + mmu_notifier_range_init(range, mm, address & PMD_MASK, + (address & PMD_MASK) + PMD_SIZE); + mmu_notifier_invalidate_range_start(range); ... so it's fine to call range_init() *here*. @@ -4069,17 +4070,17 @@ static int __follow_pte_pmd(struct mm_struct *mm, unsign ed long address, [...] if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) goto out; - if (start && end) { - *start = address & PAGE_MASK; - *end = *start + PAGE_SIZE; - mmu_notifier_invalidate_range_start(mm, *start, *end); + if (range) { + range->start = address & PAGE_MASK; + range->end = range->start + PAGE_SIZE; + mmu_notifier_invalidate_range_start(range); ... but then *not* here later in the same function? You're not making any sense.