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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 7FFAAC43214 for ; Thu, 29 Jul 2021 12:58:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4CFED608FB for ; Thu, 29 Jul 2021 12:58:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4CFED608FB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id F0F288E0001; Thu, 29 Jul 2021 08:58:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EBFAF8D0003; Thu, 29 Jul 2021 08:58:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D67658E0001; Thu, 29 Jul 2021 08:58:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0079.hostedemail.com [216.40.44.79]) by kanga.kvack.org (Postfix) with ESMTP id A09018D0003 for ; Thu, 29 Jul 2021 08:58:00 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 5C54BAC0C for ; Thu, 29 Jul 2021 12:58:00 +0000 (UTC) X-FDA: 78415627920.01.E054F02 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf13.hostedemail.com (Postfix) with ESMTP id 6BDE81006898 for ; Thu, 29 Jul 2021 12:57:59 +0000 (UTC) Received: from dggeme703-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Gb9TG4cBPz81HB; Thu, 29 Jul 2021 20:54:10 +0800 (CST) Received: from huawei.com (10.175.124.27) by dggeme703-chm.china.huawei.com (10.1.199.99) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Thu, 29 Jul 2021 20:57:56 +0800 From: Miaohe Lin To: , , , CC: , , , , , , , , , Subject: [PATCH 4/5] mm, memcg: avoid possible NULL pointer dereferencing in mem_cgroup_init() Date: Thu, 29 Jul 2021 20:57:54 +0800 Message-ID: <20210729125755.16871-5-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20210729125755.16871-1-linmiaohe@huawei.com> References: <20210729125755.16871-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggeme703-chm.china.huawei.com (10.1.199.99) X-CFilter-Loop: Reflected Authentication-Results: imf13.hostedemail.com; dkim=none; spf=pass (imf13.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=none) header.from=huawei.com X-Rspamd-Server: rspam02 X-Stat-Signature: n493c6g5qqcjmbq1dbbdg7g8q96mmhj8 X-Rspamd-Queue-Id: 6BDE81006898 X-HE-Tag: 1627563479-537623 Content-Transfer-Encoding: quoted-printable 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: rtpn might be NULL in very rare case. We have better to check it before dereferencing it. Since memcg can live with NULL rb_tree_per_node in soft_limit_tree, warn this case and continue. Signed-off-by: Miaohe Lin --- mm/memcontrol.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 5b4592d1e0f2..70a32174e7c4 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7109,6 +7109,8 @@ static int __init mem_cgroup_init(void) rtpn =3D kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node_online(node) ? node : NUMA_NO_NODE); =20 + if (WARN_ON_ONCE(!rtpn)) + continue; rtpn->rb_root =3D RB_ROOT; rtpn->rb_rightmost =3D NULL; spin_lock_init(&rtpn->lock); --=20 2.23.0