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=-14.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 06A40C433E0 for ; Tue, 30 Mar 2021 12:24:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7354619B7 for ; Tue, 30 Mar 2021 12:24:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232008AbhC3MYK (ORCPT ); Tue, 30 Mar 2021 08:24:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232035AbhC3MYF (ORCPT ); Tue, 30 Mar 2021 08:24:05 -0400 Received: from mail-wm1-x32a.google.com (mail-wm1-x32a.google.com [IPv6:2a00:1450:4864:20::32a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9F1AC061574; Tue, 30 Mar 2021 05:24:04 -0700 (PDT) Received: by mail-wm1-x32a.google.com with SMTP id y124-20020a1c32820000b029010c93864955so10179397wmy.5; Tue, 30 Mar 2021 05:24:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=t6bHlh4iN848EgwXhR/A8dHyz1llMv9ESr2FRYnonlI=; b=SY2n5LrgSNaVS1tMB3uh50SB2jBOt+dvJHuugwhblNmnOym3agWnZpSAK9G3spz4DR eVSopxpqbEe4HUcl0q6y+pkMvO3tRepo9NRj4jDqQMjOFSuTN5ct6I6zlnB94ZKSdsCr ggRpX6bnhQfVcPs7H7/EMuC9esI4E5x+UnSdke3qPaNxsLOpOQvvnBjl+a33ULOoT54Q zCCJbzl2DYR01Bpl9T8RP6FR1c9XmRoNG2OZzb8UzOSvRdkI1BKQ3aIFOxYvBBWLYd+P DZR+AkIlFAh+YPWcOLdco2bowNKC1/QtKcrYP8O/kDDBXO6widOusNPema3SwhPzGxgS 3Ekg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=t6bHlh4iN848EgwXhR/A8dHyz1llMv9ESr2FRYnonlI=; b=XeFR8bl81hzUG4rjPpH6rEANd+wc2G0A+QsEl5w01L3tTmaLRgCwESSFoiq7KGvjGM 6+ByR6Wr5aAJuAql1xqasQAXSFkfIgP0jgq21+BO3Z+fgrIeV9v+OSzhg+oui9K7y4Tr ZG2Qly3BfCCBRMNliUXZr7/a2V5P5TuzItXwqnD14nNoCDoWnP9TOGskNlT37eUggXaz r3G4aHYWD+dahwfbVrp3ypjbjrA2F9ChgomKdko1X3VjE5X5VTLJ27b2Bu+k+agApwUg G6hXpmtPcImGLhB1AlG3I548g0xCPj9OJwQJmPbv4cf1QVTJDNGQm4asFiai4pP20GH/ n+Gw== X-Gm-Message-State: AOAM5301AGuda4veHEr6JAvOnUr3l5Xg8JtP0a/7T6qo6kcLO2qpl52p 17P71+OWu3PBgaKL5fEnaNhC4dWZpm0= X-Google-Smtp-Source: ABdhPJykyIExmPNW+GMlCZmhQCmd4oSeozELPjNVugHlrPhpeTOSFqeKVTXNPID4i3Qk9bD0kF3FXw== X-Received: by 2002:a7b:c4d1:: with SMTP id g17mr3842316wmk.101.1617107043676; Tue, 30 Mar 2021 05:24:03 -0700 (PDT) Received: from [192.168.1.101] ([37.167.251.74]) by smtp.gmail.com with ESMTPSA id m17sm35483219wrx.92.2021.03.30.05.24.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 30 Mar 2021 05:24:03 -0700 (PDT) Subject: Re: [PATCH net-next v3 7/7] mld: add mc_lock for protecting per-interface mld data From: Eric Dumazet To: Taehee Yoo , netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org Cc: jwi@linux.ibm.com, kgraul@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, mareklindner@neomailbox.ch, sw@simonwunderlich.de, a@unstable.cc, sven@narfation.org, yoshfuji@linux-ipv6.org, dsahern@kernel.org, linux-s390@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org References: <20210325161657.10517-1-ap420073@gmail.com> <20210325161657.10517-8-ap420073@gmail.com> Message-ID: Date: Tue, 30 Mar 2021 14:24:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 3/30/21 1:59 PM, Eric Dumazet wrote: > > > On 3/25/21 5:16 PM, Taehee Yoo wrote: >> The purpose of this lock is to avoid a bottleneck in the query/report >> event handler logic. >> >> By previous patches, almost all mld data is protected by RTNL. >> So, the query and report event handler, which is data path logic >> acquires RTNL too. Therefore if a lot of query and report events >> are received, it uses RTNL for a long time. >> So it makes the control-plane bottleneck because of using RTNL. >> In order to avoid this bottleneck, mc_lock is added. >> >> mc_lock protect only per-interface mld data and per-interface mld >> data is used in the query/report event handler logic. >> So, no longer rtnl_lock is needed in the query/report event handler logic. >> Therefore bottleneck will be disappeared by mc_lock. >> > > What testsuite have you run exactly to validate this monster patch ? > > Have you used CONFIG_LOCKDEP=y / CONFIG_DEBUG_ATOMIC_SLEEP=y ? > >> Suggested-by: Cong Wang >> Signed-off-by: Taehee Yoo > > [...] > >> /* >> - * device multicast group del >> + * device multicast group del >> */ >> int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr) >> { >> @@ -943,8 +967,9 @@ int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr) >> >> ASSERT_RTNL(); >> >> + mutex_lock(&idev->mc_lock); >> for (map = &idev->mc_list; >> - (ma = rtnl_dereference(*map)); >> + (ma = mc_dereference(*map, idev)); >> map = &ma->next) { >> if (ipv6_addr_equal(&ma->mca_addr, addr)) { >> if (--ma->mca_users == 0) { > > This can be called with rcu_bh held, thus : > > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:928 > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4624, name: kworker/1:2 > 4 locks held by kworker/1:2/4624: > #0: ffff88802135d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] > #0: ffff88802135d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] > #0: ffff88802135d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] > #0: ffff88802135d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] > #0: ffff88802135d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] > #0: ffff88802135d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x871/0x1600 kernel/workqueue.c:2246 > #1: ffffc90009adfda8 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1600 kernel/workqueue.c:2250 > #2: ffffffff8d66d328 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4572 > #3: ffffffff8bf74300 (rcu_read_lock_bh){....}-{1:2}, at: addrconf_verify_rtnl+0x2b/0x1150 net/ipv6/addrconf.c:4459 > Preemption disabled at: > [] local_bh_disable include/linux/bottom_half.h:19 [inline] > [] rcu_read_lock_bh include/linux/rcupdate.h:727 [inline] > [] addrconf_verify_rtnl+0x41/0x1150 net/ipv6/addrconf.c:4461 > CPU: 1 PID: 4624 Comm: kworker/1:2 Not tainted 5.12.0-rc4-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Workqueue: ipv6_addrconf addrconf_verify_work > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x141/0x1d7 lib/dump_stack.c:120 > ___might_sleep.cold+0x1f1/0x237 kernel/sched/core.c:8328 > __mutex_lock_common kernel/locking/mutex.c:928 [inline] > __mutex_lock+0xa9/0x1120 kernel/locking/mutex.c:1096 > __ipv6_dev_mc_dec+0x5f/0x340 net/ipv6/mcast.c:970 > addrconf_leave_solict net/ipv6/addrconf.c:2182 [inline] > addrconf_leave_solict net/ipv6/addrconf.c:2174 [inline] > __ipv6_ifa_notify+0x5b6/0xa90 net/ipv6/addrconf.c:6077 > ipv6_ifa_notify net/ipv6/addrconf.c:6100 [inline] > ipv6_del_addr+0x463/0xae0 net/ipv6/addrconf.c:1294 > addrconf_verify_rtnl+0xd59/0x1150 net/ipv6/addrconf.c:4488 > addrconf_verify_work+0xf/0x20 net/ipv6/addrconf.c:4573 > process_one_work+0x98d/0x1600 kernel/workqueue.c:2275 > worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 > kthread+0x3b1/0x4a0 kernel/kthread.c:292 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > I will test this fix: diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 120073ffb666b18678e3145d91dac59fa865a592..8f3883f4cb4a15a0749b8f0fe00061e483ea26ca 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -4485,7 +4485,9 @@ static void addrconf_verify_rtnl(void) age >= ifp->valid_lft) { spin_unlock(&ifp->lock); in6_ifa_hold(ifp); + rcu_read_unlock_bh(); ipv6_del_addr(ifp); + rcu_read_lock_bh(); goto restart; } else if (ifp->prefered_lft == INFINITY_LIFE_TIME) { spin_unlock(&ifp->lock);