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-Tag: v4.19.255~27 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3e39da4423c6feaab42e70cbeded4ec63f2b9ff3;p=thirdparty%2Fkernel%2Fstable.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 d28fa78dedb54..436ad4bc9d4c4 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1355,7 +1355,7 @@ 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)) :