From: Kuniyuki Iwashima Date: Wed, 20 Jul 2022 16:50:14 +0000 (-0700) Subject: tcp: Fix a data-race around sysctl_tcp_adv_win_scale. X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0d8fa3c2a442cc0dded3708f081c8e95b1a94622;p=linux.git 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 --- diff --git a/include/net/tcp.h b/include/net/tcp.h index 8ce8aafeef0f5..76b0d7f2b967f 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1406,7 +1406,7 @@ 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)) :