From 6e167ed68999487347441457fe2bed81a2d90905 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 20 Jul 2022 09:50:15 -0700 Subject: [PATCH] tcp: Fix a data-race around sysctl_tcp_frto. commit 706c6202a3589f290e1ef9be0584a8f4a3cc0507 upstream. While reading sysctl_tcp_frto, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- 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 1c94051..b9fd518 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2167,7 +2167,7 @@ void tcp_enter_loss(struct sock *sk) * loss recovery is underway except recurring timeout(s) on * the same SND.UNA (sec 3.2). Disable F-RTO on path MTU probing */ - tp->frto = net->ipv4.sysctl_tcp_frto && + tp->frto = READ_ONCE(net->ipv4.sysctl_tcp_frto) && (new_recovery || icsk->icsk_retransmits) && !inet_csk(sk)->icsk_mtup.probe_size; } -- 2.7.4