From patchwork Tue Oct 18 03:47:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: shaozhengchao X-Patchwork-Id: 13009839 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 2E29BC433FE for ; Tue, 18 Oct 2022 03:42:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231547AbiJRDmw (ORCPT ); Mon, 17 Oct 2022 23:42:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231258AbiJRDmT (ORCPT ); Mon, 17 Oct 2022 23:42:19 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60170E71 for ; Mon, 17 Oct 2022 20:39:26 -0700 (PDT) Received: from dggpeml500026.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Ms00F53rBzJn6c; Tue, 18 Oct 2022 11:36:45 +0800 (CST) Received: from huawei.com (10.175.101.6) by dggpeml500026.china.huawei.com (7.185.36.106) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 18 Oct 2022 11:39:23 +0800 From: Zhengchao Shao To: , , , , , , , , , CC: , , , Subject: [PATCH net 3/3] net: sched: sfb: fix null pointer access issue when sfb_init() fails Date: Tue, 18 Oct 2022 11:47:18 +0800 Message-ID: <20221018034718.82389-4-shaozhengchao@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20221018034718.82389-1-shaozhengchao@huawei.com> References: <20221018034718.82389-1-shaozhengchao@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.101.6] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpeml500026.china.huawei.com (7.185.36.106) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org When the default qdisc is sfb, if the qdisc of dev_queue fails to be inited during mqprio_init(), sfb_reset() is invoked to clear resources. In this case, the q->qdisc is NULL, and it will cause gpf issue. The process is as follows: qdisc_create_dflt() sfb_init() tcf_block_get() --->failed, q->qdisc is NULL ... qdisc_put() ... sfb_reset() qdisc_reset(q->qdisc) --->q->qdisc is NULL ops = qdisc->ops The following is the Call Trace information: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] RIP: 0010:qdisc_reset+0x2b/0x6f0 Call Trace: sfb_reset+0x37/0xd0 qdisc_reset+0xed/0x6f0 qdisc_destroy+0x82/0x4c0 qdisc_put+0x9e/0xb0 qdisc_create_dflt+0x2c3/0x4a0 mqprio_init+0xa71/0x1760 qdisc_create+0x3eb/0x1000 tc_modify_qdisc+0x408/0x1720 rtnetlink_rcv_msg+0x38e/0xac0 netlink_rcv_skb+0x12d/0x3a0 netlink_unicast+0x4a2/0x740 netlink_sendmsg+0x826/0xcc0 sock_sendmsg+0xc5/0x100 ____sys_sendmsg+0x583/0x690 ___sys_sendmsg+0xe8/0x160 __sys_sendmsg+0xbf/0x160 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7f2164122d04 When the default qdisc is sfb, if the qdisc of dev_queue fails to be inited during mqprio_init(), sfb_reset() is invoked to clear resources. In this case, the q->qdisc is NULL, and it will cause gpf issue. Fixes: e13e02a3c68d ("net_sched: SFB flow scheduler") Signed-off-by: Zhengchao Shao --- net/sched/sch_sfb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_sfb.c b/net/sched/sch_sfb.c index e2389fa3cff8..73ae2e726512 100644 --- a/net/sched/sch_sfb.c +++ b/net/sched/sch_sfb.c @@ -455,7 +455,8 @@ static void sfb_reset(struct Qdisc *sch) { struct sfb_sched_data *q = qdisc_priv(sch); - qdisc_reset(q->qdisc); + if (likely(q->qdisc)) + qdisc_reset(q->qdisc); q->slot = 0; q->double_buffering = false; sfb_zero_all_buckets(q);