From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Baron Subject: [PATCH net] tcp: correct memory barrier usage in tcp_check_space() Date: Tue, 24 Jan 2017 21:49:41 -0500 Message-ID: <1485312581-13041-1-git-send-email-jbaron@akamai.com> Cc: netdev@vger.kernel.org, Eric Dumazet , Oleg Nesterov To: davem@davemloft.net Return-path: Received: from prod-mail-xrelay07.akamai.com ([23.79.238.175]:46900 "EHLO prod-mail-xrelay07.akamai.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751224AbdAYCyQ (ORCPT ); Tue, 24 Jan 2017 21:54:16 -0500 Sender: netdev-owner@vger.kernel.org List-ID: From: Jason Baron 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 --- 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 bfa165cc455a..1e22ae4a5b38 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5028,7 +5028,7 @@ 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); -- 2.6.1