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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1FE30C43334 for ; Mon, 20 Jun 2022 10:55:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240783AbiFTKy7 (ORCPT ); Mon, 20 Jun 2022 06:54:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234120AbiFTKyw (ORCPT ); Mon, 20 Jun 2022 06:54:52 -0400 Received: from out30-42.freemail.mail.aliyun.com (out30-42.freemail.mail.aliyun.com [115.124.30.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3BC9140BA; Mon, 20 Jun 2022 03:54:49 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=xianting.tian@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0VGvoA2z_1655722484; Received: from B-LB6YLVDL-0141.local(mailfrom:xianting.tian@linux.alibaba.com fp:SMTPD_---0VGvoA2z_1655722484) by smtp.aliyun-inc.com; Mon, 20 Jun 2022 18:54:46 +0800 Subject: Re: [PATCH 5.15] mm: validate buddy page before using To: Greg KH Cc: akpm@linux-foundation.org, ziy@nvidia.com, stable@vger.kernel.org, guoren@kernel.org, huanyi.xj@alibaba-inc.com, guohanjun@huawei.com, zjb194813@alibaba-inc.com, tianhu.hh@alibaba-inc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20220616161746.3565225-1-xianting.tian@linux.alibaba.com> <20220616161746.3565225-6-xianting.tian@linux.alibaba.com> From: Xianting Tian Message-ID: <35bd7396-f5aa-e154-9495-0a36fc6f6a33@linux.alibaba.com> Date: Mon, 20 Jun 2022 18:54:44 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/6/20 下午6:17, Greg KH 写道: > On Fri, Jun 17, 2022 at 12:17:45AM +0800, Xianting Tian wrote: >> Commit 787af64d05cd ("mm: page_alloc: validate buddy before check its migratetype.") >> fixes a bug in 1dd214b8f21c and there is a similar bug in d9dddbf55667 that >> can be fixed in a similar way too. >> >> In unset_migratetype_isolate(), we also need the fix, so move page_is_buddy() >> from mm/page_alloc.c to mm/internal.h >> >> In addition, for RISC-V arch the first 2MB RAM could be reserved for opensbi, >> so it would have pfn_base=512 and mem_map began with 512th PFN when >> CONFIG_FLATMEM=y. >> But __find_buddy_pfn algorithm thinks the start pfn 0, it could get 0 pfn or >> less than the pfn_base value. We need page_is_buddy() to verify the buddy to >> prevent accessing an invalid buddy. >> >> Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") >> Cc: stable@vger.kernel.org >> Reported-by: zjb194813@alibaba-inc.com >> Reported-by: tianhu.hh@alibaba-inc.com >> Signed-off-by: Xianting Tian >> --- >> mm/internal.h | 34 ++++++++++++++++++++++++++++++++++ >> mm/page_alloc.c | 37 +++---------------------------------- >> mm/page_isolation.c | 3 ++- >> 3 files changed, 39 insertions(+), 35 deletions(-) > What is the commit id of this in Linus's tree? It is also this one， commit 787af64d05cd528aac9ad16752d11bb1c6061bb9 Author: Zi Yan Date:   Wed Mar 30 15:45:43 2022 -0700     mm: page_alloc: validate buddy before check its migratetype.     Whenever a buddy page is found, page_is_buddy() should be called to     check its validity.  Add the missing check during pageblock merge check.     Fixes: 1dd214b8f21c ("mm: page_alloc: avoid merging non-fallbackable pageblocks with others")     Link: https://lore.kernel.org/all/20220330154208.71aca532@gandalf.local.home/     Reported-and-tested-by: Steven Rostedt     Signed-off-by: Zi Yan     Signed-off-by: Linus Torvalds > > thanks, > > greg k-h