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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C063C433F5 for ; Mon, 7 Mar 2022 02:24:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B22598D0003; Sun, 6 Mar 2022 21:24:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AD1CB8D0001; Sun, 6 Mar 2022 21:24:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9BFC18D0003; Sun, 6 Mar 2022 21:24:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id 8F1E48D0001 for ; Sun, 6 Mar 2022 21:24:07 -0500 (EST) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id 5946F12132E for ; Mon, 7 Mar 2022 02:24:07 +0000 (UTC) X-FDA: 79215995334.10.25E3A34 Received: from out30-131.freemail.mail.aliyun.com (out30-131.freemail.mail.aliyun.com [115.124.30.131]) by imf22.hostedemail.com (Postfix) with ESMTP id 6F17BC0002 for ; Mon, 7 Mar 2022 02:24:06 +0000 (UTC) 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 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 6F17BC0002 X-Stat-Signature: jpcn8ebj78ddxdjgonk4c313u1yswpw1 Authentication-Results: imf22.hostedemail.com; dkim=none; spf=pass (imf22.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.131 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=alibaba.com X-Rspam-User: X-HE-Tag: 1646619846-553175 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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.