mptcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts

While reading sysctl_tcp_thin_linear_timeouts, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. This is similar to commit 7c6f2a86ca59 ("tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts."), recently backported to stable kernels. Fixes: 8de2ed1 ("Bug#85 - meta-retransmit timeouts") Signed-off-by: Matthieu Baerts <[email protected]> (cherry picked from commit 57d2ce6) Signed-off-by: Matthieu Baerts <[email protected]> (cherry picked from commit 20091e9) Signed-off-by: Matthieu Baerts <[email protected]>
multipath-tcp · Aug 10, 2022 · b99c47a · b99c47a
1 parent 064a1b5
commit b99c47a
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/net/mptcp/mptcp_output.c b/net/mptcp/mptcp_output.c
@@ -1743,7 +1743,7 @@ void mptcp_meta_retransmit_timer(struct sock *meta_sk)
 	 * linear-timeout retransmissions into a black hole
 	 */
 	if (meta_sk->sk_state == TCP_ESTABLISHED &&
-	    (meta_tp->thin_lto || sock_net(meta_sk)->ipv4.sysctl_tcp_thin_linear_timeouts) &&
+	    (meta_tp->thin_lto || READ_ONCE(sock_net(meta_sk)->ipv4.sysctl_tcp_thin_linear_timeouts)) &&
 	    tcp_stream_is_thin(meta_tp) &&
 	    meta_icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) {
 		meta_icsk->icsk_backoff = 0;