From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932521AbeAROpU (ORCPT ); Thu, 18 Jan 2018 09:45:20 -0500 Received: from mail-wm0-f54.google.com ([74.125.82.54]:44555 "EHLO mail-wm0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932491AbeAROpS (ORCPT ); Thu, 18 Jan 2018 09:45:18 -0500 X-Google-Smtp-Source: ACJfBotA7P9chcdUtbQcphAy3l1Bi9QggjxtZLMAm1dnl5PDLkvJNsCs/wQf09/Lr7PnxqLUzwTviA== Date: Thu, 18 Jan 2018 17:45:14 +0300 From: "Kirill A. Shutemov" To: Dave Hansen Cc: Tetsuo Handa , torvalds@linux-foundation.org, kirill.shutemov@linux.intel.com, akpm@linux-foundation.org, hannes@cmpxchg.org, iamjoonsoo.kim@lge.com, mgorman@techsingularity.net, tony.luck@intel.com, vbabka@suse.cz, mhocko@kernel.org, aarcange@redhat.com, hillf.zj@alibaba-inc.com, hughd@google.com, oleg@redhat.com, peterz@infradead.org, riel@redhat.com, srikar@linux.vnet.ibm.com, vdavydov.dev@gmail.com, mingo@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Subject: Re: [mm 4.15-rc8] Random oopses under memory pressure. Message-ID: <20180118144514.njr5xdagtwzpzep6@node.shutemov.name> References: <201801160115.w0G1FOIG057203@www262.sakura.ne.jp> <201801170233.JDG21842.OFOJMQSHtOFFLV@I-love.SAKURA.ne.jp> <201801172008.CHH39543.FFtMHOOVSQJLFO@I-love.SAKURA.ne.jp> <201801181712.BFD13039.LtHOSVMFJQFOFO@I-love.SAKURA.ne.jp> <20180118122550.2lhsjx7hg5drcjo4@node.shutemov.name> <20180118131210.456oyh6fw4scwv53@node.shutemov.name> <4a6681a7-5ed6-ad9c-5d1d-73f1fcc82f3d@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4a6681a7-5ed6-ad9c-5d1d-73f1fcc82f3d@linux.intel.com> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 18, 2018 at 06:38:10AM -0800, Dave Hansen wrote: > On 01/18/2018 05:12 AM, Kirill A. Shutemov wrote: > > - if (pte_page(*pvmw->pte) - pvmw->page >= > > - hpage_nr_pages(pvmw->page)) { > > Is ->pte guaranteed to map a page which is within the same section as > pvmw->page? Otherwise, with sparsemem (non-vmemmap), the pointer > arithmetic won't work. No, it's not guaranteed. It can be arbitrary page. The arithmetic won't work because they are different "memory objects"? -- Kirill A. Shutemov