From: Kuniyuki Iwashima Date: Wed, 20 Jul 2022 16:50:24 +0000 (-0700) Subject: tcp: Fix a data-race around sysctl_tcp_min_rtt_wlen. X-Git-Tag: v6.6.17~7014^2~32^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1330ffacd05fc9ac4159d19286ce119e22450ed2;p=platform%2Fkernel%2Flinux-rpi.git tcp: Fix a data-race around sysctl_tcp_min_rtt_wlen. 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 --- diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index d386a69..96d11f8 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3058,7 +3058,7 @@ 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)) {