[PATCH net-next 1/2] mptcp: annotate a data-race around sysctl_tcp_wmem[0]

[Jason Xing <kerneljasonxing@gmail.com>]

From: Jason Xing <kernelxing@tencent.com>

It's possible that writer and the reader can manipulate the same
sysctl knob concurrently. Using READ_ONCE() to prevent reading
an old value.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 net/mptcp/protocol.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index f16edef6026a..a10ebf3ee10a 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -850,7 +850,7 @@ static inline void __mptcp_sync_sndbuf(struct sock *sk)
 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
 		return;
 
-	new_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[0];
+	new_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]);
 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
 
-- 
2.37.3