From eb6b1e505c988da7aa8068d3e3ac8a05fa1601fb Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 10 Nov 2022 20:26:11 +0800 Subject: [PATCH] tcp: Fix a data-race around sysctl_tcp_min_rtt_wlen. stable inclusion from stable-v5.10.135 commit 83edb788e69a0d5ad40ba5be6a60d6db265d0500 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5ZWFM Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=83edb788e69a0d5ad40ba5be6a60d6db265d0500 -------------------------------- [ Upstream commit 1330ffacd05fc9ac4159d19286ce119e22450ed2 ] While reading sysctl_tcp_min_rtt_wlen, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: f672258391b4 ("tcp: track min RTT using windowed min-filter") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Zheng Zengkai Reviewed-by: Wei Li --- 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 255493c4acc3..d418bdaba5bc 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3004,7 +3004,7 @@ static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una, static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us, const int flag) { - u32 wlen = sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen * HZ; + u32 wlen = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen) * HZ; struct tcp_sock *tp = tcp_sk(sk); if ((flag & FLAG_ACK_MAYBE_DELAYED) && rtt_us > tcp_min_rtt(tp)) { -- GitLab