From patchwork Wed Aug 17 10:46:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Hai X-Patchwork-Id: 12945698 X-Patchwork-Delegate: kuba@kernel.org 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 A6B7BC25B08 for ; Wed, 17 Aug 2022 10:31:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238985AbiHQKbB (ORCPT ); Wed, 17 Aug 2022 06:31:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238909AbiHQKa7 (ORCPT ); Wed, 17 Aug 2022 06:30:59 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93B02785B5; Wed, 17 Aug 2022 03:30:58 -0700 (PDT) Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4M742t6Zk7zkWKh; Wed, 17 Aug 2022 18:27:34 +0800 (CST) Received: from kwepemm600001.china.huawei.com (7.193.23.3) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 17 Aug 2022 18:30:55 +0800 Received: from huawei.com (10.175.113.133) by kwepemm600001.china.huawei.com (7.193.23.3) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 17 Aug 2022 18:30:54 +0800 From: Wang Hai To: , , , , , , , CC: , Subject: [PATCH net] net/sched: fix netdevice reference leaks in attach_one_default_qdisc() Date: Wed, 17 Aug 2022 18:46:46 +0800 Message-ID: <20220817104646.22861-1-wanghai38@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.175.113.133] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemm600001.china.huawei.com (7.193.23.3) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org In attach_default_qdiscs(), when attach default qdisc (fq_codel) fails and fallback to noqueue, if the original attached qdisc is not released and a new one is directly attached, this will cause netdevice reference leaks. The following is the bug log: veth0: default qdisc (fq_codel) fail, fallback to noqueue unregister_netdevice: waiting for veth0 to become free. Usage count = 32 leaked reference. qdisc_alloc+0x12e/0x210 qdisc_create_dflt+0x62/0x140 attach_one_default_qdisc.constprop.41+0x44/0x70 dev_activate+0x128/0x290 __dev_open+0x12a/0x190 __dev_change_flags+0x1a2/0x1f0 dev_change_flags+0x23/0x60 do_setlink+0x332/0x1150 __rtnl_newlink+0x52f/0x8e0 rtnl_newlink+0x43/0x70 rtnetlink_rcv_msg+0x140/0x3b0 netlink_rcv_skb+0x50/0x100 netlink_unicast+0x1bb/0x290 netlink_sendmsg+0x37c/0x4e0 sock_sendmsg+0x5f/0x70 ____sys_sendmsg+0x208/0x280 In attach_one_default_qdisc(), release the old one before attaching a new qdisc to fix this bug. Fixes: bf6dba76d278 ("net: sched: fallback to qdisc noqueue if default qdisc setup fail") Signed-off-by: Wang Hai --- net/sched/sch_generic.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index d47b9689eba6..87b61ef14497 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -1140,6 +1140,11 @@ static void attach_one_default_qdisc(struct net_device *dev, if (!netif_is_multiqueue(dev)) qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT; + + if (dev_queue->qdisc_sleeping && + dev_queue->qdisc_sleeping != &noop_qdisc) + qdisc_put(dev_queue->qdisc_sleeping); + dev_queue->qdisc_sleeping = qdisc; }