Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754049AbcLIN0q (ORCPT ); Fri, 9 Dec 2016 08:26:46 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:8299 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752625AbcLIN0g (ORCPT ); Fri, 9 Dec 2016 08:26:36 -0500 Subject: Re: [PATCH v2] arm64: mm: Fix memmap to be initialized for the entire section To: Hanjun Guo , Ard Biesheuvel References: <1480530091-1092-1-git-send-email-rrichter@cavium.com> <584AA257.3080608@linaro.org> CC: Robert Richter , Catalin Marinas , Will Deacon , David Daney , Mark Rutland , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" From: Yisheng Xie Message-ID: Date: Fri, 9 Dec 2016 21:15:12 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <584AA257.3080608@linaro.org> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.29.40] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2174 Lines: 60 On 2016/12/9 20:23, Hanjun Guo wrote: > On 12/09/2016 08:19 PM, Ard Biesheuvel wrote: >> On 9 December 2016 at 12:14, Yisheng Xie wrote: >>> Hi Robert, >>> We have merged your patch to 4.9.0-rc8, however we still meet the similar problem >>> on our D05 board: >>> >> >> To be clear: does this issue also occur on D05 *without* the patch? > > It boots ok on D05 without this patch. > > But I think the problem Robert described in the commit message is > still there, just not triggered in the boot. we met this problem > when having LTP stress memory test and hit the same BUG_ON. > That's right. for D05's case, when trigger the BUG_ON on: 1863 VM_BUG_ON(page_zone(start_page) != page_zone(end_page)); the end_page is not nomap, but BIOS reserved. here is the log I got: [ 0.000000] efi: 0x00003fc00000-0x00003fffffff [Reserved | | | | | | | | | | | | ] [...] [ 5.081443] move_freepages: phys(start_page: 0x20000000,end_page:0x3fff0000) For invalid pages, their zone and node information is not initialized, and it do have risk to trigger the BUG_ON, so I have a silly question, why not just change the BUG_ON: ----------- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6de9440..af199b8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1860,12 +1860,13 @@ int move_freepages(struct zone *zone, * Remove at a later date when no bug reports exist related to * grouping pages by mobility */ - VM_BUG_ON(page_zone(start_page) != page_zone(end_page)); + VM_BUG_ON(early_pfn_valid(start_page) && early_pfn_valid(end_page) && + page_zone(start_page) != page_zone(end_page)); #endif for (page = start_page; page <= end_page;) { /* Make sure we are not inadvertently changing nodes */ - VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); + VM_BUG_ON_PAGE(early_pfn_valid(page) && (page_to_nid(page) != zone_to_nid(zone)), page); if (!pfn_valid_within(page_to_pfn(page))) { page++; Thanks, Yisheng Xie > Thanks > Hanjun > > . >