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 69E1A1990C for ; Tue, 9 May 2023 22:50:57 +0000 (UTC) Received: from smtp-fw-6001.amazon.com (smtp-fw-6001.amazon.com [52.95.48.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F27F59E7 for ; Tue, 9 May 2023 15:50:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1683672656; x=1715208656; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=J6ZIkHPBoIcJJY37qVqyF2jj6r9q+FxrIswaOiGh2XU=; b=oo5ZCIva2YwlMraNbF3GU3HImdxUHauozszuhSubdzy5UjYIb6J+dDY4 JvdsoOFG3WsSypQCW+Pj4RZnFCxGcTbNEDrWz3h99bPzafv3Yt1taFEOR D/2CKGuEzSbrKqtCmD2SzcElpE4gSZMvU/VdKdXPQR/CGf+4VTmzVrLN/ A=; X-IronPort-AV: E=Sophos;i="5.99,263,1677542400"; d="scan'208";a="330009610" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-pdx-2a-m6i4x-1cca8d67.us-west-2.amazon.com) ([10.43.8.2]) by smtp-border-fw-6001.iad6.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 May 2023 22:50:53 +0000 Received: from EX19MTAUWA002.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-pdx-2a-m6i4x-1cca8d67.us-west-2.amazon.com (Postfix) with ESMTPS id D6F2E81365; Tue, 9 May 2023 22:50:51 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX19MTAUWA002.ant.amazon.com (10.250.64.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Tue, 9 May 2023 22:50:45 +0000 Received: from 88665a182662.ant.amazon.com (10.187.171.39) 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; Tue, 9 May 2023 22:50:41 +0000 From: Kuniyuki Iwashima To: CC: , , , , , Subject: Re: [PATCH net] net: datagram: fix data-races in datagram_poll() Date: Tue, 9 May 2023 15:50:31 -0700 Message-ID: <20230509225031.19553-1-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230509173131.3263780-1-edumazet@google.com> References: <20230509173131.3263780-1-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: [10.187.171.39] X-ClientProxiedBy: EX19D032UWB002.ant.amazon.com (10.13.139.190) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: Bulk X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE, T_SPF_PERMERROR autolearn=ham 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: Tue, 9 May 2023 17:31:31 +0000 > datagram_poll() runs locklessly, we should add READ_ONCE() > annotations while reading sk->sk_err, sk->sk_shutdown and sk->sk_state. > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima > --- > net/core/datagram.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/net/core/datagram.c b/net/core/datagram.c > index 5662dff3d381a92b271d9cba38a28a6a8478c114..176eb58347461b160890ce2d6b2d3cbc7412e321 100644 > --- a/net/core/datagram.c > +++ b/net/core/datagram.c > @@ -807,18 +807,21 @@ __poll_t datagram_poll(struct file *file, struct socket *sock, > { > struct sock *sk = sock->sk; > __poll_t mask; > + u8 shutdown; > > sock_poll_wait(file, sock, wait); > mask = 0; > > /* exceptional events? */ > - if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue)) > + if (READ_ONCE(sk->sk_err) || > + !skb_queue_empty_lockless(&sk->sk_error_queue)) > mask |= EPOLLERR | > (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0); > > - if (sk->sk_shutdown & RCV_SHUTDOWN) > + shutdown = READ_ONCE(sk->sk_shutdown); > + if (shutdown & RCV_SHUTDOWN) > mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM; > - if (sk->sk_shutdown == SHUTDOWN_MASK) > + if (shutdown == SHUTDOWN_MASK) > mask |= EPOLLHUP; > > /* readable? */ > @@ -827,10 +830,12 @@ __poll_t datagram_poll(struct file *file, struct socket *sock, > > /* Connection-based need to check for termination and startup */ > if (connection_based(sk)) { > - if (sk->sk_state == TCP_CLOSE) > + int state = READ_ONCE(sk->sk_state); > + > + if (state == TCP_CLOSE) > mask |= EPOLLHUP; > /* connection hasn't started yet? */ > - if (sk->sk_state == TCP_SYN_SENT) > + if (state == TCP_SYN_SENT) > return mask; > } > > -- > 2.40.1.521.gf1e218fcd8-goog