From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1061450-1521802375-2-4060585508254533743 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521802374; b=l6uvMsOytVorHDC50rqWiNP5DsaT0fD0fnZBVkcwrUsUA0N YGzxuAUXa30aGxUAf/mPX5d2thtcq5eGb2y2sqrQcpFtFe5NPZ9aOhJgzYJurK/K bMoUbMWrVM3AiCzO1QX8gBxOa7U8gIF5ebAw/M4CKCxR41XkCQbzWCCULqatow2i gi7c2+2vp6+yLLnVQZI2BZSy6g1+IOfToujqS0Gypla/VZ52MouEUZ+vv1vZgjzQ cCUWZC0HaeZhLpmQUB0+fv5lR0RSWjwi2GN7D1QtOPZrqVAZ5hKt0kIMuMka7lMD Xpg5PWHjD6jRMEVNiX3vL7yBs11R05V2e7q6wEg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1521802374; bh=YfYXgSBYn76hOaymaB+2WDBO3U 0IdiTiLkz7A7bQd6Q=; b=vjSPsctthWO81gnr0TDY5NfKxZDO60O4Nyk5xqp4+g hFifE51Lroy0u8ncZSXvK69MvuQgfFU9Ndvg4/8efZKywgLuJwOehIzf/E6ZoXow fX8spA9ex/USIDRgxeNz/tIwUyqxJ0kYQV1IXaq48JarkAu9uD+FdfjV04Ghxs0b EMCkZ4V8fOua1B9uiC8rPcFo6GMghl9yWIyKJdwDONCyBeBG3/lKM8WiADXL+rt6 bS7MxOVCpswKHH5x+T+KaT1byNrejNhmkFd85gfq+J0a6dA9yx7ydpBKIpujozpz KMqSt7TDLpbvTaH1AV7U6JgEb0ZH53vpnuT5y4AgYyhQ== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755946AbeCWKN7 (ORCPT ); Fri, 23 Mar 2018 06:13:59 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45014 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755901AbeCWKN4 (ORCPT ); Fri, 23 Mar 2018 06:13:56 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Yuchung Cheng , "David S. Miller" , Sasha Levin Subject: [PATCH 4.4 28/97] tcp: remove poll() flakes with FastOpen Date: Fri, 23 Mar 2018 10:54:15 +0100 Message-Id: <20180323094159.200488589@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180323094157.535925724@linuxfoundation.org> References: <20180323094157.535925724@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 0f9fa831aecfc297b7b45d4f046759bcefcf87f0 ] When using TCP FastOpen for an active session, we send one wakeup event from tcp_finish_connect(), right before the data eventually contained in the received SYNACK is queued to sk->sk_receive_queue. This means that depending on machine load or luck, poll() users might receive POLLOUT events instead of POLLIN|POLLOUT To fix this, we need to move the call to sk->sk_state_change() after the (optional) call to tcp_rcv_fastopen_synack() Signed-off-by: Eric Dumazet Acked-by: Yuchung Cheng Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_input.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5464,10 +5464,6 @@ void tcp_finish_connect(struct sock *sk, else tp->pred_flags = 0; - if (!sock_flag(sk, SOCK_DEAD)) { - sk->sk_state_change(sk); - sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); - } } static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack, @@ -5531,6 +5527,7 @@ static int tcp_rcv_synsent_state_process struct tcp_sock *tp = tcp_sk(sk); struct tcp_fastopen_cookie foc = { .len = -1 }; int saved_clamp = tp->rx_opt.mss_clamp; + bool fastopen_fail; tcp_parse_options(skb, &tp->rx_opt, 0, &foc); if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr) @@ -5633,10 +5630,15 @@ static int tcp_rcv_synsent_state_process tcp_finish_connect(sk, skb); - if ((tp->syn_fastopen || tp->syn_data) && - tcp_rcv_fastopen_synack(sk, skb, &foc)) - return -1; + fastopen_fail = (tp->syn_fastopen || tp->syn_data) && + tcp_rcv_fastopen_synack(sk, skb, &foc); + if (!sock_flag(sk, SOCK_DEAD)) { + sk->sk_state_change(sk); + sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); + } + if (fastopen_fail) + return -1; if (sk->sk_write_pending || icsk->icsk_accept_queue.rskq_defer_accept || icsk->icsk_ack.pingpong) {