diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
index f23fda0c55a7..ef65e2df709f 100644
--- a/net/mptcp/mib.c
+++ b/net/mptcp/mib.c
@@ -85,6 +85,8 @@ static const struct snmp_mib mptcp_snmp_list[] = {
 	SNMP_MIB_ITEM("SimultConnectFallback", MPTCP_MIB_SIMULTCONNFALLBACK),
 	SNMP_MIB_ITEM("FallbackFailed", MPTCP_MIB_FALLBACKFAILED),
 	SNMP_MIB_ITEM("WinProbe", MPTCP_MIB_WINPROBE),
+	SNMP_MIB_ITEM("BacklogDrop", MPTCP_MIB_BACKLOGDROP),
+	SNMP_MIB_ITEM("RcvPruned", MPTCP_MIB_RCVPRUNED),
 };
 
 /* mptcp_mib_alloc - allocate percpu mib counters
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index 812218b5ed2b..9271205f682e 100644
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -88,6 +88,8 @@ enum linux_mptcp_mib_field {
 	MPTCP_MIB_SIMULTCONNFALLBACK,	/* Simultaneous connect */
 	MPTCP_MIB_FALLBACKFAILED,	/* Can't fallback due to msk status */
 	MPTCP_MIB_WINPROBE,		/* MPTCP-level zero window probe */
+	MPTCP_MIB_BACKLOGDROP,		/* Backlog over memory limit */
+	MPTCP_MIB_RCVPRUNED,		/* Dropped due to memory constraints */
 	__MPTCP_MIB_MAX
 };
 
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 1057d500577b..b8318e030138 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1190,8 +1190,34 @@ static bool add_addr_hmac_valid(struct mptcp_sock *msk,
 	return hmac == mp_opt->ahmac;
 }
 
-/* Return false in case of error (or subflow has been reset),
- * else return true.
+static bool mptcp_over_limit(struct sock *sk, struct sock *ssk,
+			     const struct sk_buff *skb)
+{
+	struct mptcp_sock *msk = mptcp_sk(sk);
+	u32 rcvbuf = READ_ONCE(sk->sk_rcvbuf);
+
+	if (likely((u32)sk_rmem_alloc_get(sk) <= rcvbuf &&
+		   READ_ONCE(msk->backlog_len) <= rcvbuf))
+		return false;
+
+	/* Avoid silently dropping pure acks, fin, rst or already-acked segm. */
+	if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq ||
+	    TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_FIN | TCPHDR_RST) ||
+	    !after(TCP_SKB_CB(skb)->end_seq, tcp_sk(ssk)->rcv_nxt))
+		return false;
+
+	/* Dropped due to memory constraints, schedule an ack. */
+	inet_csk(ssk)->icsk_ack.pending |= ICSK_ACK_NOMEM | ICSK_ACK_NOW;
+	inet_csk_schedule_ack(ssk);
+
+	/* Plain TCP (fallback) and skb is dropped before the TCP recv queue. */
+	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
+
+	return true;
+}
+
+/* Return false when the caller must drop the packet, i.e. in case of error,
+ * subflow has been reset, or over memory limits.
  */
 bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 {
@@ -1217,7 +1243,7 @@ bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 
 		__mptcp_data_acked(subflow->conn);
 		mptcp_data_unlock(subflow->conn);
-		return true;
+		return !mptcp_over_limit(subflow->conn, sk, skb);
 	}
 
 	mptcp_get_options(skb, &mp_opt);
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 09cd3c1f3cdb..cfb77a32518a 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -387,6 +387,16 @@ static bool __mptcp_move_skb(struct sock *sk, struct sk_buff *skb)
 
 	mptcp_borrow_fwdmem(sk, skb);
 
+	/* Can't drop packets for fallback socket this late, or the stream
+	 * will break.
+	 */
+	if (unlikely(sk_rmem_alloc_get(sk) > READ_ONCE(sk->sk_rcvbuf)) &&
+	    !__mptcp_check_fallback(msk)) {
+		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
+		mptcp_drop(sk, skb);
+		return false;
+	}
+
 	if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
 		/* in sequence */
 		msk->bytes_received += copy_len;
@@ -681,6 +691,7 @@ static void __mptcp_add_backlog(struct sock *sk,
 	struct sk_buff *tail = NULL;
 	struct sock *ssk = skb->sk;
 	bool fragstolen;
+	u64 limit;
 	int delta;
 
 	if (unlikely(sk->sk_state == TCP_CLOSE)) {
@@ -688,6 +699,16 @@ static void __mptcp_add_backlog(struct sock *sk,
 		return;
 	}
 
+	/* Similar additional allowance as plain TCP. */
+	limit = READ_ONCE(sk->sk_rcvbuf);
+	limit += (limit >> 1) + 64 * 1024;
+	limit = min_t(u64, limit, UINT_MAX);
+	if (msk->backlog_len > limit && !__mptcp_check_fallback(msk)) {
+		__MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_BACKLOGDROP);
+		kfree_skb_reason(skb, SKB_DROP_REASON_SOCKET_BACKLOG);
+		return;
+	}
+
 	/* Try to coalesce with the last skb in our backlog */
 	if (!list_empty(&msk->backlog_list))
 		tail = list_last_entry(&msk->backlog_list, struct sk_buff, list);
@@ -759,7 +780,7 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 
 			mptcp_init_skb(ssk, skb, offset, len);
 
-			if (own_msk && sk_rmem_alloc_get(sk) < sk->sk_rcvbuf) {
+			if (own_msk) {
 				mptcp_subflow_lend_fwdmem(subflow, skb);
 				ret |= __mptcp_move_skb(sk, skb);
 			} else {
@@ -2210,10 +2231,6 @@ static bool __mptcp_move_skbs(struct sock *sk, struct list_head *skbs, u32 *delt
 
 	*delta = 0;
 	while (1) {
-		/* If the msk recvbuf is full stop, don't drop */
-		if (sk_rmem_alloc_get(sk) > sk->sk_rcvbuf)
-			break;
-
 		prefetch(skb->next);
 		list_del(&skb->list);
 		*delta += skb->truesize;
@@ -2241,9 +2258,7 @@ static bool mptcp_can_spool_backlog(struct sock *sk, struct list_head *skbs)
 	DEBUG_NET_WARN_ON_ONCE(msk->backlog_unaccounted && sk->sk_socket &&
 			       mem_cgroup_from_sk(sk));
 
-	/* Don't spool the backlog if the rcvbuf is full. */
-	if (list_empty(&msk->backlog_list) ||
-	    sk_rmem_alloc_get(sk) > sk->sk_rcvbuf)
+	if (list_empty(&msk->backlog_list))
 		return false;
 
 	INIT_LIST_HEAD(skbs);