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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 57DAEC04E53 for ; Wed, 15 May 2019 11:08:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 289D120862 for ; Wed, 15 May 2019 11:08:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557918515; bh=K6fm4fvYABgpTi7wF0dxNT5efY5YR8ML0YmMa9FRLqw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Z9YlZIf1qUY5hgPRxc7GnhYzJ5Et0DKluwRLCSWAvVAs/7lC7u0K0sieB2ngrp3u5 LoLIUVaDRr8s7ECjtYl5BkHg526ZizVs+w2ZMl/8UREs3HCv5uAdqiD6jP0A8gxLq9 +n7IjiQ8IXlZirzReA9LN3ntuH6xJ3KifCdV0SSU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729124AbfEOLIe (ORCPT ); Wed, 15 May 2019 07:08:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:40830 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728615AbfEOLI2 (ORCPT ); Wed, 15 May 2019 07:08:28 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 244F020644; Wed, 15 May 2019 11:08:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557918507; bh=K6fm4fvYABgpTi7wF0dxNT5efY5YR8ML0YmMa9FRLqw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Co6lfgH0e9379BpEbDj77T8BtbR6gDm9Y47s0BjWouakV0eZjVEgv6/LyyXXQfDsF 6rKTFuvbzdAzA3gN2Wix880depp7IZz4gEtfOOFKKFreRkk1H3rxyG51PbQZrEo/Rr eNkMHtf/SnYXiBMTRGN6LTqOo7DCBoM9k92vaiy4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Baozeng Ding , Marcelo Ricardo Leitner , Cong Wang , "David S. Miller" , Zubin Mithra Subject: [PATCH 4.4 156/266] ipv6: fix a potential deadlock in do_ipv6_setsockopt() Date: Wed, 15 May 2019 12:54:23 +0200 Message-Id: <20190515090728.190012520@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190515090722.696531131@linuxfoundation.org> References: <20190515090722.696531131@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: WANG Cong commit 8651be8f14a12d24f203f283601d9b0418c389ff upstream. Baozeng reported this deadlock case: CPU0 CPU1 ---- ---- lock([ 165.136033] sk_lock-AF_INET6); lock([ 165.136033] rtnl_mutex); lock([ 165.136033] sk_lock-AF_INET6); lock([ 165.136033] rtnl_mutex); Similar to commit 87e9f0315952 ("ipv4: fix a potential deadlock in mcast getsockopt() path") this is due to we still have a case, ipv6_sock_mc_close(), where we acquire sk_lock before rtnl_lock. Close this deadlock with the similar solution, that is always acquire rtnl lock first. Fixes: baf606d9c9b1 ("ipv4,ipv6: grab rtnl before locking the socket") Reported-by: Baozeng Ding Tested-by: Baozeng Ding Cc: Marcelo Ricardo Leitner Signed-off-by: Cong Wang Reviewed-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller Cc: Zubin Mithra Signed-off-by: Greg Kroah-Hartman --- include/net/addrconf.h | 1 + net/ipv6/ipv6_sockglue.c | 3 ++- net/ipv6/mcast.c | 17 ++++++++++++----- 3 files changed, 15 insertions(+), 6 deletions(-) --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -162,6 +162,7 @@ int ipv6_sock_mc_join(struct sock *sk, i const struct in6_addr *addr); int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr); +void __ipv6_sock_mc_close(struct sock *sk); void ipv6_sock_mc_close(struct sock *sk); bool inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr, const struct in6_addr *src_addr); --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -121,6 +121,7 @@ struct ipv6_txoptions *ipv6_update_optio static bool setsockopt_needs_rtnl(int optname) { switch (optname) { + case IPV6_ADDRFORM: case IPV6_ADD_MEMBERSHIP: case IPV6_DROP_MEMBERSHIP: case IPV6_JOIN_ANYCAST: @@ -199,7 +200,7 @@ static int do_ipv6_setsockopt(struct soc } fl6_free_socklist(sk); - ipv6_sock_mc_close(sk); + __ipv6_sock_mc_close(sk); /* * Sock is moving from IPv6 to IPv4 (sk_prot), so --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -276,16 +276,14 @@ static struct inet6_dev *ip6_mc_find_dev return idev; } -void ipv6_sock_mc_close(struct sock *sk) +void __ipv6_sock_mc_close(struct sock *sk) { struct ipv6_pinfo *np = inet6_sk(sk); struct ipv6_mc_socklist *mc_lst; struct net *net = sock_net(sk); - if (!rcu_access_pointer(np->ipv6_mc_list)) - return; + ASSERT_RTNL(); - rtnl_lock(); while ((mc_lst = rtnl_dereference(np->ipv6_mc_list)) != NULL) { struct net_device *dev; @@ -303,8 +301,17 @@ void ipv6_sock_mc_close(struct sock *sk) atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc); kfree_rcu(mc_lst, rcu); - } +} + +void ipv6_sock_mc_close(struct sock *sk) +{ + struct ipv6_pinfo *np = inet6_sk(sk); + + if (!rcu_access_pointer(np->ipv6_mc_list)) + return; + rtnl_lock(); + __ipv6_sock_mc_close(sk); rtnl_unlock(); }