From: Kuniyuki Iwashima Date: Mon, 18 Jul 2022 17:26:47 +0000 (-0700) Subject: tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts. X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7c6f2a86ca590d5187a073d987e9599985fb1c7c;p=linux.git tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts. While reading sysctl_tcp_thin_linear_timeouts, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 36e31b0af587 ("net: TCP thin linear timeouts") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller --- diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index ec5277becc6a1..50bba370486e8 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -578,7 +578,7 @@ out_reset_timer: * linear-timeout retransmissions into a black hole */ if (sk->sk_state == TCP_ESTABLISHED && - (tp->thin_lto || net->ipv4.sysctl_tcp_thin_linear_timeouts) && + (tp->thin_lto || READ_ONCE(net->ipv4.sysctl_tcp_thin_linear_timeouts)) && tcp_stream_is_thin(tp) && icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) { icsk->icsk_backoff = 0;