From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A1BEE2770A for ; Fri, 26 May 2023 16:23:43 +0000 (UTC) Received: from smtp-fw-52005.amazon.com (smtp-fw-52005.amazon.com [52.119.213.156]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FA8D1BC for ; Fri, 26 May 2023 09:23:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1685118218; x=1716654218; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=wqre3bxxTbDd5AE2xCdQtiYMSqdjU5WnIDUeEmEF/eU=; b=TCPvZykFXt4umwXJeYseCUCPb5DixmrecWrzbWj/aaXqTpZudn5RSn66 vc6vuPngNu49z4tqZp2P+j22bpKp4SMJVo6AuEKfx3y6xvMkG3v2a4siE /KfhHslFdMoOlKM+ZdufLNLgB0sqR0jbYB3BACdr0SyQPOqWXXSrN4SNI I=; X-IronPort-AV: E=Sophos;i="6.00,194,1681171200"; d="scan'208";a="585615736" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-pdx-2b-m6i4x-32fb4f1a.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-52005.iad7.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 May 2023 16:23:35 +0000 Received: from EX19MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2b-m6i4x-32fb4f1a.us-west-2.amazon.com (Postfix) with ESMTPS id ED49CC1642; Fri, 26 May 2023 16:23:33 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX19MTAUWB001.ant.amazon.com (10.250.64.248) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Fri, 26 May 2023 16:23:33 +0000 Received: from 88665a182662.ant.amazon.com (10.88.130.94) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Fri, 26 May 2023 16:23:31 +0000 From: Kuniyuki Iwashima To: CC: , , , , , , Subject: [PATCH net] af_packet: do not use READ_ONCE() in packet_bind() Date: Fri, 26 May 2023 09:23:20 -0700 Message-ID: <20230526162320.5816-1-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230526154342.2533026-1-edumazet@google.com> References: <20230526154342.2533026-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.88.130.94] X-ClientProxiedBy: EX19D046UWB001.ant.amazon.com (10.13.139.187) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: Bulk X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE,T_SPF_PERMERROR autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net From: Eric Dumazet Date: Fri, 26 May 2023 15:43:42 +0000 > A recent patch added READ_ONCE() in packet_bind() and packet_bind_spkt() > > This is better handled by reading pkt_sk(sk)->num later > in packet_do_bind() while appropriate lock is held. > > READ_ONCE() in writers are often an evidence of something being wrong. > > Fixes: 822b5a1c17df ("af_packet: Fix data-races of pkt_sk(sk)->num.") > Signed-off-by: Eric Dumazet > Cc: Kuniyuki Iwashima > Cc: Willem de Bruijn Reviewed-by: Kuniyuki Iwashima Thanks! > --- > net/packet/af_packet.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c > index a1f9a0e9f3c8a72e5a95f96473b7b6c63f893935..a2dbeb264f260e5b8923ece9aac99fe19ddfeb62 100644 > --- a/net/packet/af_packet.c > +++ b/net/packet/af_packet.c > @@ -3201,6 +3201,9 @@ static int packet_do_bind(struct sock *sk, const char *name, int ifindex, > > lock_sock(sk); > spin_lock(&po->bind_lock); > + if (!proto) > + proto = po->num; > + > rcu_read_lock(); > > if (po->fanout) { > @@ -3299,7 +3302,7 @@ static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr, > memcpy(name, uaddr->sa_data, sizeof(uaddr->sa_data_min)); > name[sizeof(uaddr->sa_data_min)] = 0; > > - return packet_do_bind(sk, name, 0, READ_ONCE(pkt_sk(sk)->num)); > + return packet_do_bind(sk, name, 0, 0); > } > > static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) > @@ -3316,8 +3319,7 @@ static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len > if (sll->sll_family != AF_PACKET) > return -EINVAL; > > - return packet_do_bind(sk, NULL, sll->sll_ifindex, > - sll->sll_protocol ? : READ_ONCE(pkt_sk(sk)->num)); > + return packet_do_bind(sk, NULL, sll->sll_ifindex, sll->sll_protocol); > } > > static struct proto packet_proto = { > -- > 2.41.0.rc0.172.g3f132b7071-goog