diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e44a3da12b96eb..1dacc072dcca36 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -890,6 +890,7 @@ static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
 	mptcp_sockopt_sync_locked(msk, ssk);
 	mptcp_subflow_joined(msk, ssk);
 	mptcp_stop_tout_timer(sk);
+	__mptcp_propagate_sndbuf(sk, ssk);
 	return true;
 }
 
@@ -1076,15 +1077,16 @@ static void mptcp_enter_memory_pressure(struct sock *sk)
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	bool first = true;
 
-	sk_stream_moderate_sndbuf(sk);
 	mptcp_for_each_subflow(msk, subflow) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 
 		if (first)
 			tcp_enter_memory_pressure(ssk);
 		sk_stream_moderate_sndbuf(ssk);
+
 		first = false;
 	}
+	__mptcp_sync_sndbuf(sk);
 }
 
 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of
@@ -2458,6 +2460,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 		WRITE_ONCE(msk->first, NULL);
 
 out:
+	__mptcp_sync_sndbuf(sk);
 	if (need_push)
 		__mptcp_push_pending(sk, 0);
 
@@ -3224,7 +3227,7 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk,
 	 * uses the correct data
 	 */
 	mptcp_copy_inaddrs(nsk, ssk);
-	mptcp_propagate_sndbuf(nsk, ssk);
+	__mptcp_propagate_sndbuf(nsk, ssk);
 
 	mptcp_rcv_space_init(msk, ssk);
 	bh_unlock_sock(nsk);
@@ -3402,6 +3405,8 @@ static void mptcp_release_cb(struct sock *sk)
 			__mptcp_set_connected(sk);
 		if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
 			__mptcp_error_report(sk);
+		if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags))
+			__mptcp_sync_sndbuf(sk);
 	}
 
 	__mptcp_update_rmem(sk);
@@ -3446,6 +3451,14 @@ void mptcp_subflow_process_delegated(struct sock *ssk, long status)
 			__set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
 		mptcp_data_unlock(sk);
 	}
+	if (status & BIT(MPTCP_DELEGATE_SNDBUF)) {
+		mptcp_data_lock(sk);
+		if (!sock_owned_by_user(sk))
+			__mptcp_sync_sndbuf(sk);
+		else
+			__set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags);
+		mptcp_data_unlock(sk);
+	}
 	if (status & BIT(MPTCP_DELEGATE_ACK))
 		schedule_3rdack_retransmission(ssk);
 }
@@ -3530,6 +3543,7 @@ bool mptcp_finish_join(struct sock *ssk)
 	/* active subflow, already present inside the conn_list */
 	if (!list_empty(&subflow->node)) {
 		mptcp_subflow_joined(msk, ssk);
+		mptcp_propagate_sndbuf(parent, ssk);
 		return true;
 	}
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 5971d34a3dee60..9092fcf1879878 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -125,6 +125,7 @@
 #define MPTCP_RETRANSMIT	4
 #define MPTCP_FLUSH_JOIN_LIST	5
 #define MPTCP_CONNECTED		6
+#define MPTCP_SYNC_SNDBUF	7
 
 struct mptcp_skb_cb {
 	u64 map_seq;
@@ -445,6 +446,7 @@ DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
 #define MPTCP_DELEGATE_SCHEDULED	0
 #define MPTCP_DELEGATE_SEND		1
 #define MPTCP_DELEGATE_ACK		2
+#define MPTCP_DELEGATE_SNDBUF		3
 
 #define MPTCP_DELEGATE_ACTIONS_MASK	(~BIT(MPTCP_DELEGATE_SCHEDULED))
 /* MPTCP subflow context */
@@ -518,6 +520,9 @@ struct mptcp_subflow_context {
 
 	u32	setsockopt_seq;
 	u32	stale_rcv_tstamp;
+	int     cached_sndbuf;	    /* sndbuf size when last synced with the msk sndbuf,
+				     * protected by the msk socket lock
+				     */
 
 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
 	struct	sock *conn;	    /* parent mptcp_sock */
@@ -780,13 +785,52 @@ static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
 }
 
-static inline bool mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
+static inline void __mptcp_sync_sndbuf(struct sock *sk)
 {
-	if ((sk->sk_userlocks & SOCK_SNDBUF_LOCK) || ssk->sk_sndbuf <= READ_ONCE(sk->sk_sndbuf))
-		return false;
+	struct mptcp_subflow_context *subflow;
+	int ssk_sndbuf, new_sndbuf;
+
+	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
+		return;
+
+	new_sndbuf = 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);
+
+		subflow->cached_sndbuf = ssk_sndbuf;
+		new_sndbuf += ssk_sndbuf;
+	}
+
+	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
+	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
+}
+
+/* The called held both the msk socket and the subflow socket locks,
+ * possibly under BH
+ */
+static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+
+	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
+		__mptcp_sync_sndbuf(sk);
+}
+
+/* the caller held only the subflow socket lock, either in process or
+ * BH context. Additionally this can be called under the msk data lock,
+ * so we can't acquire such lock here: let the delegate action acquires
+ * the needed locks in suitable order.
+ */
+static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+
+	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
+		return;
 
-	WRITE_ONCE(sk->sk_sndbuf, ssk->sk_sndbuf);
-	return true;
+	local_bh_disable();
+	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
+	local_bh_enable();
 }
 
 static inline void mptcp_write_space(struct sock *sk)
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 72858d7d8974bc..574e221bb765ae 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -95,6 +95,7 @@ static void mptcp_sol_socket_sync_intval(struct mptcp_sock *msk, int optname, in
 		case SO_SNDBUFFORCE:
 			ssk->sk_userlocks |= SOCK_SNDBUF_LOCK;
 			WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
+			mptcp_subflow_ctx(ssk)->cached_sndbuf = sk->sk_sndbuf;
 			break;
 		case SO_RCVBUF:
 		case SO_RCVBUFFORCE:
@@ -1415,8 +1416,10 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
 
 	if (sk->sk_userlocks & tx_rx_locks) {
 		ssk->sk_userlocks |= sk->sk_userlocks & tx_rx_locks;
-		if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
+		if (sk->sk_userlocks & SOCK_SNDBUF_LOCK) {
 			WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
+			mptcp_subflow_ctx(ssk)->cached_sndbuf = sk->sk_sndbuf;
+		}
 		if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
 			WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
 	}
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index df208666fd19f4..2b43577f952e75 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -421,6 +421,7 @@ static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct soc
 
 void __mptcp_set_connected(struct sock *sk)
 {
+	__mptcp_propagate_sndbuf(sk, mptcp_sk(sk)->first);
 	if (sk->sk_state == TCP_SYN_SENT) {
 		inet_sk_state_store(sk, TCP_ESTABLISHED);
 		sk->sk_state_change(sk);
@@ -472,7 +473,6 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 		return;
 
 	msk = mptcp_sk(parent);
-	mptcp_propagate_sndbuf(parent, sk);
 	subflow->rel_write_seq = 1;
 	subflow->conn_finished = 1;
 	subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
@@ -1736,7 +1736,6 @@ static void subflow_state_change(struct sock *sk)
 
 	msk = mptcp_sk(parent);
 	if (subflow_simultaneous_connect(sk)) {
-		mptcp_propagate_sndbuf(parent, sk);
 		mptcp_do_fallback(sk);
 		mptcp_rcv_space_init(msk, sk);
 		pr_fallback(msk);