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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 0865CC3A59F for ; Mon, 26 Aug 2019 23:16:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D54E220850 for ; Mon, 26 Aug 2019 23:16:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727086AbfHZXQW (ORCPT ); Mon, 26 Aug 2019 19:16:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36586 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726552AbfHZXQV (ORCPT ); Mon, 26 Aug 2019 19:16:21 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B88DC30821C1; Mon, 26 Aug 2019 23:16:20 +0000 (UTC) Received: from new-host.redhat.com (ovpn-204-34.brq.redhat.com [10.40.204.34]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5B2645D9E1; Mon, 26 Aug 2019 23:16:18 +0000 (UTC) From: Davide Caratti To: Cong Wang , Jamal Hadi Salim , Jiri Pirko , "David S. Miller" , netdev@vger.kernel.org Cc: Paolo Abeni , Li Shuang Subject: [PATCH net] net/sched: pfifo_fast: fix wrong dereference when qdisc is reset Date: Tue, 27 Aug 2019 01:15:16 +0200 Message-Id: <0598164c6e32684e57c7656f0b8aca0813c51f42.1566861256.git.dcaratti@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Mon, 26 Aug 2019 23:16:21 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of 'TCQ_F_NOLOCK' bit in the parent qdisc, we need to be sure that per-cpu counters are present when 'reset()' is called for pfifo_fast qdiscs. Otherwise, the following script: # tc q a dev lo handle 1: root htb default 100 # tc c a dev lo parent 1: classid 1:100 htb \ > rate 95Mbit ceil 100Mbit burst 64k [...] # tc f a dev lo parent 1: protocol arp basic classid 1:100 [...] # tc q a dev lo parent 1:100 handle 100: pfifo_fast [...] # tc q d dev lo root can generate the following splat: Unable to handle kernel paging request at virtual address dfff2c01bd148000 Mem abort info: ESR = 0x96000004 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 [dfff2c01bd148000] address between user and kernel address ranges Internal error: Oops: 96000004 [#1] SMP [...] pstate: 80000005 (Nzcv daif -PAN -UAO) pc : pfifo_fast_reset+0x280/0x4d8 lr : pfifo_fast_reset+0x21c/0x4d8 sp : ffff800d09676fa0 x29: ffff800d09676fa0 x28: ffff200012ee22e4 x27: dfff200000000000 x26: 0000000000000000 x25: ffff800ca0799958 x24: ffff1001940f332b x23: 0000000000000007 x22: ffff200012ee1ab8 x21: 0000600de8a40000 x20: 0000000000000000 x19: ffff800ca0799900 x18: 0000000000000000 x17: 0000000000000002 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: ffff1001b922e6e2 x11: 1ffff001b922e6e1 x10: 0000000000000000 x9 : 1ffff001b922e6e1 x8 : dfff200000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 1fffe400025dc45c x4 : 1fffe400025dc357 x3 : 00000c01bd148000 x2 : 0000600de8a40000 x1 : 0000000000000007 x0 : 0000600de8a40004 Call trace: pfifo_fast_reset+0x280/0x4d8 qdisc_reset+0x6c/0x370 htb_reset+0x150/0x3b8 [sch_htb] qdisc_reset+0x6c/0x370 dev_deactivate_queue.constprop.5+0xe0/0x1a8 dev_deactivate_many+0xd8/0x908 dev_deactivate+0xe4/0x190 qdisc_graft+0x88c/0xbd0 tc_get_qdisc+0x418/0x8a8 rtnetlink_rcv_msg+0x3a8/0xa78 netlink_rcv_skb+0x18c/0x328 rtnetlink_rcv+0x28/0x38 netlink_unicast+0x3c4/0x538 netlink_sendmsg+0x538/0x9a0 sock_sendmsg+0xac/0xf8 ___sys_sendmsg+0x53c/0x658 __sys_sendmsg+0xc8/0x140 __arm64_sys_sendmsg+0x74/0xa8 el0_svc_handler+0x164/0x468 el0_svc+0x10/0x14 Code: 910012a0 92400801 d343fc03 11000c21 (38fb6863) Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags', before dereferencing 'qdisc->cpu_stats'. Fixes: 8a53e616de29 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too") CC: Paolo Abeni Reported-by: Li Shuang Signed-off-by: Davide Caratti --- net/sched/sch_generic.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 11c03cf4aa74..c89b787785a1 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -688,12 +688,14 @@ static void pfifo_fast_reset(struct Qdisc *qdisc) kfree_skb(skb); } - for_each_possible_cpu(i) { - struct gnet_stats_queue *q = per_cpu_ptr(qdisc->cpu_qstats, i); + if (qdisc_is_percpu_stats(qdisc)) + for_each_possible_cpu(i) { + struct gnet_stats_queue *q = + per_cpu_ptr(qdisc->cpu_qstats, i); - q->backlog = 0; - q->qlen = 0; - } + q->backlog = 0; + q->qlen = 0; + } } static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb) -- 2.20.1