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tcp: Fix a data-race around sysctl_tcp_adv_win_scale.

While reading sysctl_tcp_adv_win_scale, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

Kuniyuki Iwashima committed 4 years ago

Commit 36eeee71 parent 02ca5271 file · +1 −1Browse files

Unified · Split

include/net/tcp.h+1−1
@@ -1419,7 +1419,7 @@ void tcp_select_initial_window(const struct sock *sk, int __space, · 1418 unmodified lines
1419 1419
1420static inline int tcp_win_from_space(const struct sock *sk, int space)1420static inline int tcp_win_from_space(const struct sock *sk, int space)
1421{1421{
1422 int tcp_adv_win_scale = sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale;1422 int tcp_adv_win_scale = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale);
1423 1423
1424 return tcp_adv_win_scale <= 0 ?1424 return tcp_adv_win_scale <= 0 ?
1425 (space>>(-tcp_adv_win_scale)) :1425 (space>>(-tcp_adv_win_scale)) :