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 0438E1ED38 for ; Tue, 25 Jul 2023 11:33:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B49CC433C8; Tue, 25 Jul 2023 11:33:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690284824; bh=5VFXx3C39PMQMlHae/LjuHkr4497WP2EMMz6y0oEslg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZlS9yVG9sUbfpwLnwCzJtXv2LrtsN65DUsYKpsoD1KM4VuGRrqOgcZiuaJSDNhLUw oXG2FGGOj4HxcyoCRu23gzXo+jAu+Q6DP6FtyBevTSEtHm3ZYfl9YSpEckHwtFAd/J cvdXEGzJWbHjs2oqmba1EZZNjk+SPNljQ6HZbWAs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 494/509] tcp: annotate data-races around tp->keepalive_time Date: Tue, 25 Jul 2023 12:47:13 +0200 Message-ID: <20230725104616.375044127@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230725104553.588743331@linuxfoundation.org> References: <20230725104553.588743331@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 4164245c76ff906c9086758e1c3f87082a7f5ef5 ] do_tcp_getsockopt() reads tp->keepalive_time while another cpu might change its value. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/r/20230719212857.3943972-4-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/tcp.h | 7 +++++-- net/ipv4/tcp.c | 3 ++- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index e231101e5001b..92de7c049f19e 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1459,9 +1459,12 @@ static inline int keepalive_intvl_when(const struct tcp_sock *tp) static inline int keepalive_time_when(const struct tcp_sock *tp) { struct net *net = sock_net((struct sock *)tp); + int val; - return tp->keepalive_time ? : - READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); + /* Paired with WRITE_ONCE() in tcp_sock_set_keepidle_locked() */ + val = READ_ONCE(tp->keepalive_time); + + return val ? : READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); } static inline int keepalive_probes(const struct tcp_sock *tp) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 39919d1436cea..053e4880d8f0f 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3093,7 +3093,8 @@ int tcp_sock_set_keepidle_locked(struct sock *sk, int val) if (val < 1 || val > MAX_TCP_KEEPIDLE) return -EINVAL; - tp->keepalive_time = val * HZ; + /* Paired with WRITE_ONCE() in keepalive_time_when() */ + WRITE_ONCE(tp->keepalive_time, val * HZ); if (sock_flag(sk, SOCK_KEEPOPEN) && !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) { u32 elapsed = keepalive_time_elapsed(tp); -- 2.39.2