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 774BD17AAB for ; Wed, 9 Aug 2023 11:31:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBCE0C433C7; Wed, 9 Aug 2023 11:31:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691580704; bh=25KzkZxL9Oa1fQLs1ftWPMHWJ1ED70rZ+se6X73M6w8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EnOPAWKy8HIaaO/1QtUshknT2DjuM3RqCbwYdrqmkqXdckZ3UEwhbzVpDSgQSOT5a Z88LILsFvLkqDjNRaPsKicsH0RtUMrdRlkwpb+q5EAw2pZ8uRiNVkeE1y2wPQSQn2J zZldIGYGit5XZDmXhEUjXSGYDhyA8BzY+CbU3jNI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , David Ahern , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 120/154] tcp_metrics: annotate data-races around tm->tcpm_net Date: Wed, 9 Aug 2023 12:42:31 +0200 Message-ID: <20230809103640.887894154@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103636.887175326@linuxfoundation.org> References: <20230809103636.887175326@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 d5d986ce42c71a7562d32c4e21e026b0f87befec ] tm->tcpm_net can be read or written locklessly. Instead of changing write_pnet() and read_pnet() and potentially hurt performance, add the needed READ_ONCE()/WRITE_ONCE() in tm_net() and tcpm_new(). Fixes: 849e8a0ca8d5 ("tcp_metrics: Add a field tcpm_net and verify it matches on lookup") Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://lore.kernel.org/r/20230802131500.1478140-6-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/tcp_metrics.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 29261aa96eb40..3d0452bb6c2a1 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -40,7 +40,7 @@ struct tcp_fastopen_metrics { struct tcp_metrics_block { struct tcp_metrics_block __rcu *tcpm_next; - possible_net_t tcpm_net; + struct net *tcpm_net; struct inetpeer_addr tcpm_saddr; struct inetpeer_addr tcpm_daddr; unsigned long tcpm_stamp; @@ -51,9 +51,10 @@ struct tcp_metrics_block { struct rcu_head rcu_head; }; -static inline struct net *tm_net(struct tcp_metrics_block *tm) +static inline struct net *tm_net(const struct tcp_metrics_block *tm) { - return read_pnet(&tm->tcpm_net); + /* Paired with the WRITE_ONCE() in tcpm_new() */ + return READ_ONCE(tm->tcpm_net); } static bool tcp_metric_locked(struct tcp_metrics_block *tm, @@ -197,7 +198,9 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, if (!tm) goto out_unlock; } - write_pnet(&tm->tcpm_net, net); + /* Paired with the READ_ONCE() in tm_net() */ + WRITE_ONCE(tm->tcpm_net, net); + tm->tcpm_saddr = *saddr; tm->tcpm_daddr = *daddr; -- 2.40.1