From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5A73415AE3 for ; Wed, 9 Aug 2023 10:45:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF2D5C433C8; Wed, 9 Aug 2023 10:45:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691577951; bh=pbAWn0GIPDOBEjh/Kx1OFk/aogDtGU0NGwB5qsTjY3E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yi2m+kLADITfto0c5QJCiCZ7AbJ2NxE/6Q6g27UFBRy6vEGAGioTsjQKjtLHur9kh ZHFJxKYUsQ+mZy70K57nOVeDXf6UcpgH53732O5TKtqE1hwvPBDTLNzQ9xUlU8quxf Qr8GnEle6n8FhMzHcdZfAGbyOTJGEgpx5TYV9XlE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Akhmat Karakotov , "David S. Miller" , Sasha Levin Subject: [PATCH 6.4 052/165] net: annotate data-race around sk->sk_txrehash Date: Wed, 9 Aug 2023 12:39:43 +0200 Message-ID: <20230809103644.521772870@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103642.720851262@linuxfoundation.org> References: <20230809103642.720851262@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Eric Dumazet [ Upstream commit c76a0328899bbe226f8adeb88b8da9e4167bd316 ] sk_getsockopt() runs locklessly. This means sk->sk_txrehash can be read while other threads are changing its value. Other locations were handled in commit cb6cd2cec799 ("tcp: Change SYN ACK retransmit behaviour to account for rehash") Fixes: 26859240e4ee ("txhash: Add socket option to control TX hash rethink behavior") Signed-off-by: Eric Dumazet Cc: Akhmat Karakotov Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/sock.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index 7b88290ddc6e7..b25511e7e8103 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1523,7 +1523,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname, } if ((u8)val == SOCK_TXREHASH_DEFAULT) val = READ_ONCE(sock_net(sk)->core.sysctl_txrehash); - /* Paired with READ_ONCE() in tcp_rtx_synack() */ + /* Paired with READ_ONCE() in tcp_rtx_synack() + * and sk_getsockopt(). + */ WRITE_ONCE(sk->sk_txrehash, (u8)val); break; @@ -1930,7 +1932,8 @@ int sk_getsockopt(struct sock *sk, int level, int optname, break; case SO_TXREHASH: - v.val = sk->sk_txrehash; + /* Paired with WRITE_ONCE() in sk_setsockopt() */ + v.val = READ_ONCE(sk->sk_txrehash); break; default: -- 2.40.1