tcp: Fix data-races around sysctl_tcp_dsack.

[mirror_ubuntu-jammy-kernel.git] / net / ipv4 / tcp_input.c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2d21d8bf3b8cc0c39127b93021803f7185bb5143..e066c527a723fa619c7759b66589a4d64e06fd68 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4419,7 +4419,7 @@ static void tcp_dsack_set(struct sock *sk, u32 seq, u32 end_seq)
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
-       if (tcp_is_sack(tp) && sock_net(sk)->ipv4.sysctl_tcp_dsack) {
+       if (tcp_is_sack(tp) && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_dsack)) {
                int mib_idx;
 
                if (before(seq, tp->rcv_nxt))
@@ -4466,7 +4466,7 @@ static void tcp_send_dupack(struct sock *sk, const struct sk_buff *skb)
                NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST);
                tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
 
-               if (tcp_is_sack(tp) && sock_net(sk)->ipv4.sysctl_tcp_dsack) {
+               if (tcp_is_sack(tp) && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_dsack)) {
                        u32 end_seq = TCP_SKB_CB(skb)->end_seq;
 
                        tcp_rcv_spurious_retrans(sk, skb);