From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752791AbdKVXLE (ORCPT ); Wed, 22 Nov 2017 18:11:04 -0500 Received: from omzsmtpe02.verizonbusiness.com ([199.249.25.209]:30815 "EHLO omzsmtpe02.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752638AbdKVW0F (ORCPT ); Wed, 22 Nov 2017 17:26:05 -0500 From: alexander.levin@verizon.com Cc: Jason Baron , Eric Dumazet , Oleg Nesterov , "David S . Miller" , alexander.levin@verizon.com X-Host: endeavour.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.9 41/54] tcp: correct memory barrier usage in tcp_check_space() Thread-Topic: [PATCH AUTOSEL for 4.9 41/54] tcp: correct memory barrier usage in tcp_check_space() Thread-Index: AQHTY+CYvn/rZa9gzUKi7J/b7wHQ/A== Date: Wed, 22 Nov 2017 22:24:01 +0000 Message-ID: <20171122222344.19782-41-alexander.levin@verizon.com> References: <20171122222344.19782-1-alexander.levin@verizon.com> In-Reply-To: <20171122222344.19782-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vAMNBOq4001311 From: Jason Baron [ Upstream commit 56d806222ace4c3aeae516cd7a855340fb2839d8 ] sock_reset_flag() maps to __clear_bit() not the atomic version clear_bit(). Thus, we need smp_mb(), smp_mb__after_atomic() is not sufficient. Fixes: 3c7151275c0c ("tcp: add memory barriers to write space paths") Cc: Eric Dumazet Cc: Oleg Nesterov Signed-off-by: Jason Baron Acked-by: Eric Dumazet Reported-by: Oleg Nesterov Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 8fcd0c642742..05255a286888 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5081,7 +5081,7 @@ static void tcp_check_space(struct sock *sk) if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) { sock_reset_flag(sk, SOCK_QUEUE_SHRUNK); /* pairs with tcp_poll() */ - smp_mb__after_atomic(); + smp_mb(); if (sk->sk_socket && test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) tcp_new_space(sk); -- 2.11.0