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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 92357C433FE for ; Thu, 10 Dec 2020 09:28:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4ADEF23D9E for ; Thu, 10 Dec 2020 09:28:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732367AbgLJJ2j (ORCPT ); Thu, 10 Dec 2020 04:28:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:38984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726763AbgLJJ2f (ORCPT ); Thu, 10 Dec 2020 04:28:35 -0500 Date: Thu, 10 Dec 2020 10:29:09 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1607592474; bh=9IBGE7YExpBUElirt6uWH7rWMH+57P9GaY6SS3rQU1k=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=qY5DJbue3kOO4ieeWJO79wbG8Pr/Dlgx50r4S6Ki7OrXc/Drj0uHpOZfs1OEPsQjP XVmgGZlyqPEnL1zxrDXgmYAvHsvC6VdJLofAa3tNB40G+FOlQTA8/k7r3o915Wr0FQ Cw+5C1Jqhi5eFc4Tns+qeTWz0p0yS9AphA3iZiEM= From: Greg KH To: Mike Rapoport Cc: Andrew Morton , Andrea Arcangeli , Baoquan He , David Hildenbrand , Mel Gorman , Michal Hocko , Mike Rapoport , Qian Cai , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org Subject: Re: [PATCH v2 2/2] mm: fix initialization of struct page for holes in memory layout Message-ID: References: <20201209214304.6812-1-rppt@kernel.org> <20201209214304.6812-3-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201209214304.6812-3-rppt@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 09, 2020 at 11:43:04PM +0200, Mike Rapoport wrote: > From: Mike Rapoport > > There could be struct pages that are not backed by actual physical memory. > This can happen when the actual memory bank is not a multiple of > SECTION_SIZE or when an architecture does not register memory holes > reserved by the firmware as memblock.memory. > > Such pages are currently initialized using init_unavailable_mem() function > that iterated through PFNs in holes in memblock.memory and if there is a > struct page corresponding to a PFN, the fields if this page are set to > default values and it is marked as Reserved. > > init_unavailable_mem() does not take into account zone and node the page > belongs to and sets both zone and node links in struct page to zero. > > On a system that has firmware reserved holes in a zone above ZONE_DMA, for > instance in a configuration below: > > # grep -A1 E820 /proc/iomem > 7a17b000-7a216fff : Unknown E820 type > 7a217000-7bffffff : System RAM > > unset zone link in struct page will trigger > > VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page); > > because there are pages in both ZONE_DMA32 and ZONE_DMA (unset zone link in > struct page) in the same pageblock. > > Interleave initialization of pages that correspond to holes with the > initialization of memory map, so that zone and node information will be > properly set on such pages. > > Fixes: 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather > that check each PFN") > Reported-by: Andrea Arcangeli > Signed-off-by: Mike Rapoport > --- > mm/page_alloc.c | 152 +++++++++++++++++++++--------------------------- > 1 file changed, 65 insertions(+), 87 deletions(-) This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.