From 312ce3901fd8c1194601457fc22e0f7932f0f28b Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 20 Jul 2022 09:50:14 -0700 Subject: [PATCH] tcp: Fix a data-race around sysctl_tcp_adv_win_scale. commit 36eeee75ef0157e42fb6593dcc65daab289b559e upstream. While reading sysctl_tcp_adv_win_scale, 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 --- include/net/tcp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 44bfb22069c1..8129ce9a0771 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1396,7 +1396,7 @@ void tcp_select_initial_window(const struct sock *sk, int __space, static inline int tcp_win_from_space(const struct sock *sk, int space) { - int tcp_adv_win_scale = sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale; + int tcp_adv_win_scale = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale); return tcp_adv_win_scale <= 0 ? (space>>(-tcp_adv_win_scale)) :