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 0E09CC433F5 for ; Mon, 7 Mar 2022 02:24:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234237AbiCGCZF (ORCPT ); Sun, 6 Mar 2022 21:25:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233256AbiCGCZC (ORCPT ); Sun, 6 Mar 2022 21:25:02 -0500 Received: from out30-43.freemail.mail.aliyun.com (out30-43.freemail.mail.aliyun.com [115.124.30.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C7695A0AA for ; Sun, 6 Mar 2022 18:24:07 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R991e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04357;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=20;SR=0;TI=SMTPD_---0V6Oarp-_1646619840; Received: from 30.97.48.83(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0V6Oarp-_1646619840) by smtp.aliyun-inc.com(127.0.0.1); Mon, 07 Mar 2022 10:24:01 +0800 Message-ID: Date: Mon, 7 Mar 2022 10:25:03 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH 14/16] mm/migration: fix potential invalid node access for reclaim-based migration To: Miaohe Lin , akpm@linux-foundation.org Cc: mike.kravetz@oracle.com, shy828301@gmail.com, willy@infradead.org, ying.huang@intel.com, ziy@nvidia.com, minchan@kernel.org, apopple@nvidia.com, ave.hansen@linux.intel.com, o451686892@gmail.com, almasrymina@google.com, jhubbard@nvidia.com, rcampbell@nvidia.com, peterx@redhat.com, naoya.horiguchi@nec.com, mhocko@suse.com, riel@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20220304093409.25829-1-linmiaohe@huawei.com> <20220304093409.25829-15-linmiaohe@huawei.com> From: Baolin Wang In-Reply-To: <20220304093409.25829-15-linmiaohe@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/4/2022 5:34 PM, Miaohe Lin wrote: > If we failed to setup hotplug state callbacks for mm/demotion:online in > some corner cases, node_demotion will be left uninitialized. Invalid node > might be returned from the next_demotion_node() when doing reclaim-based > migration. Use kcalloc to allocate node_demotion to fix the issue. > > Fixes: ac16ec835314 ("mm: migrate: support multiple target nodes demotion") > Signed-off-by: Miaohe Lin > --- > mm/migrate.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 279940c0c064..7b1c0b988234 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -2516,9 +2516,9 @@ static int __init migrate_on_reclaim_init(void) > { > int ret; > > - node_demotion = kmalloc_array(nr_node_ids, > - sizeof(struct demotion_nodes), > - GFP_KERNEL); > + node_demotion = kcalloc(nr_node_ids, > + sizeof(struct demotion_nodes), > + GFP_KERNEL); Nit: not sure if this is worthy of this rare corner case, but I think the target demotion nodes' default value should be NUMA_NO_NODE instead of 0.