diff --git a/drivers/bluetooth/virtio_bt.c b/drivers/bluetooth/virtio_bt.c
index 67c21263f9e0..fd281d439505 100644
--- a/drivers/bluetooth/virtio_bt.c
+++ b/drivers/bluetooth/virtio_bt.c
@@ -219,7 +219,7 @@ static void virtbt_rx_work(struct work_struct *work)
 	if (!skb)
 		return;
 
-	skb->len = len;
+	skb_put(skb, len);
 	virtbt_rx_handle(vbt, skb);
 
 	if (virtbt_add_inbuf(vbt) < 0)
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 7a59c4487050..a6c12863a253 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -1067,10 +1067,21 @@ int hci_conn_del(struct hci_conn *conn)
 			hdev->acl_cnt += conn->sent;
 	} else {
 		struct hci_conn *acl = conn->link;
+
 		if (acl) {
 			acl->link = NULL;
 			hci_conn_drop(acl);
 		}
+
+		/* Unacked ISO frames */
+		if (conn->type == ISO_LINK) {
+			if (hdev->iso_pkts)
+				hdev->iso_cnt += conn->sent;
+			else if (hdev->le_pkts)
+				hdev->le_cnt += conn->sent;
+			else
+				hdev->acl_cnt += conn->sent;
+		}
 	}
 
 	if (conn->amp_mgr)
@@ -1761,6 +1772,7 @@ struct hci_conn *hci_bind_cis(struct hci_dev *hdev, bdaddr_t *dst,
 		if (!cis)
 			return ERR_PTR(-ENOMEM);
 		cis->cleanup = cis_cleanup;
+		cis->dst_type = dst_type;
 	}
 
 	if (cis->state == BT_CONNECTED)
@@ -2140,12 +2152,6 @@ struct hci_conn *hci_connect_cis(struct hci_dev *hdev, bdaddr_t *dst,
 	struct hci_conn *le;
 	struct hci_conn *cis;
 
-	/* Convert from ISO socket address type to HCI address type  */
-	if (dst_type == BDADDR_LE_PUBLIC)
-		dst_type = ADDR_LE_DEV_PUBLIC;
-	else
-		dst_type = ADDR_LE_DEV_RANDOM;
-
 	if (hci_dev_test_flag(hdev, HCI_ADVERTISING))
 		le = hci_connect_le(hdev, dst, dst_type, false,
 				    BT_SECURITY_LOW,
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 613039ba5dbf..f825857db6d0 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -235,6 +235,14 @@ static int iso_chan_add(struct iso_conn *conn, struct sock *sk,
 	return err;
 }
 
+static inline u8 le_addr_type(u8 bdaddr_type)
+{
+	if (bdaddr_type == BDADDR_LE_PUBLIC)
+		return ADDR_LE_DEV_PUBLIC;
+	else
+		return ADDR_LE_DEV_RANDOM;
+}
+
 static int iso_connect_bis(struct sock *sk)
 {
 	struct iso_conn *conn;
@@ -328,14 +336,16 @@ static int iso_connect_cis(struct sock *sk)
 	/* Just bind if DEFER_SETUP has been set */
 	if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags)) {
 		hcon = hci_bind_cis(hdev, &iso_pi(sk)->dst,
-				    iso_pi(sk)->dst_type, &iso_pi(sk)->qos);
+				    le_addr_type(iso_pi(sk)->dst_type),
+				    &iso_pi(sk)->qos);
 		if (IS_ERR(hcon)) {
 			err = PTR_ERR(hcon);
 			goto done;
 		}
 	} else {
 		hcon = hci_connect_cis(hdev, &iso_pi(sk)->dst,
-				       iso_pi(sk)->dst_type, &iso_pi(sk)->qos);
+				       le_addr_type(iso_pi(sk)->dst_type),
+				       &iso_pi(sk)->qos);
 		if (IS_ERR(hcon)) {
 			err = PTR_ERR(hcon);
 			goto done;
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 1f34b82ca0ec..9c24947aa41e 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1990,7 +1990,7 @@ static struct l2cap_chan *l2cap_global_chan_by_psm(int state, __le16 psm,
 		if (link_type == LE_LINK && c->src_type == BDADDR_BREDR)
 			continue;
 
-		if (c->psm == psm) {
+		if (c->chan_type != L2CAP_CHAN_FIXED && c->psm == psm) {
 			int src_match, dst_match;
 			int src_any, dst_any;
 
@@ -3764,7 +3764,8 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data
 			l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC,
 					   sizeof(rfc), (unsigned long) &rfc, endptr - ptr);
 
-			if (test_bit(FLAG_EFS_ENABLE, &chan->flags)) {
+			if (remote_efs &&
+			    test_bit(FLAG_EFS_ENABLE, &chan->flags)) {
 				chan->remote_id = efs.id;
 				chan->remote_stype = efs.stype;
 				chan->remote_msdu = le16_to_cpu(efs.msdu);
@@ -5813,6 +5814,19 @@ static int l2cap_le_connect_req(struct l2cap_conn *conn,
 	BT_DBG("psm 0x%2.2x scid 0x%4.4x mtu %u mps %u", __le16_to_cpu(psm),
 	       scid, mtu, mps);
 
+	/* BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 3, Part A
+	 * page 1059:
+	 *
+	 * Valid range: 0x0001-0x00ff
+	 *
+	 * Table 4.15: L2CAP_LE_CREDIT_BASED_CONNECTION_REQ SPSM ranges
+	 */
+	if (!psm || __le16_to_cpu(psm) > L2CAP_PSM_LE_DYN_END) {
+		result = L2CAP_CR_LE_BAD_PSM;
+		chan = NULL;
+		goto response;
+	}
+
 	/* Check if we have socket listening on psm */
 	pchan = l2cap_global_chan_by_psm(BT_LISTEN, psm, &conn->hcon->src,
 					 &conn->hcon->dst, LE_LINK);
@@ -6001,6 +6015,18 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
 
 	psm  = req->psm;
 
+	/* BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 3, Part A
+	 * page 1059:
+	 *
+	 * Valid range: 0x0001-0x00ff
+	 *
+	 * Table 4.15: L2CAP_LE_CREDIT_BASED_CONNECTION_REQ SPSM ranges
+	 */
+	if (!psm || __le16_to_cpu(psm) > L2CAP_PSM_LE_DYN_END) {
+		result = L2CAP_CR_LE_BAD_PSM;
+		goto response;
+	}
+
 	BT_DBG("psm 0x%2.2x mtu %u mps %u", __le16_to_cpu(psm), mtu, mps);
 
 	memset(&pdu, 0, sizeof(pdu));
@@ -6885,6 +6911,7 @@ static int l2cap_rx_state_recv(struct l2cap_chan *chan,
 			       struct l2cap_ctrl *control,
 			       struct sk_buff *skb, u8 event)
 {
+	struct l2cap_ctrl local_control;
 	int err = 0;
 	bool skb_in_use = false;
 
@@ -6909,15 +6936,32 @@ static int l2cap_rx_state_recv(struct l2cap_chan *chan,
 			chan->buffer_seq = chan->expected_tx_seq;
 			skb_in_use = true;
 
+			/* l2cap_reassemble_sdu may free skb, hence invalidate
+			 * control, so make a copy in advance to use it after
+			 * l2cap_reassemble_sdu returns and to avoid the race
+			 * condition, for example:
+			 *
+			 * The current thread calls:
+			 *   l2cap_reassemble_sdu
+			 *     chan->ops->recv == l2cap_sock_recv_cb
+			 *       __sock_queue_rcv_skb
+			 * Another thread calls:
+			 *   bt_sock_recvmsg
+			 *     skb_recv_datagram
+			 *     skb_free_datagram
+			 * Then the current thread tries to access control, but
+			 * it was freed by skb_free_datagram.
+			 */
+			local_control = *control;
 			err = l2cap_reassemble_sdu(chan, skb, control);
 			if (err)
 				break;
 
-			if (control->final) {
+			if (local_control.final) {
 				if (!test_and_clear_bit(CONN_REJ_ACT,
 							&chan->conn_state)) {
-					control->final = 0;
-					l2cap_retransmit_all(chan, control);
+					local_control.final = 0;
+					l2cap_retransmit_all(chan, &local_control);
 					l2cap_ertm_send(chan);
 				}
 			}
@@ -7297,11 +7341,27 @@ static int l2cap_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,
 static int l2cap_stream_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,
 			   struct sk_buff *skb)
 {
+	/* l2cap_reassemble_sdu may free skb, hence invalidate control, so store
+	 * the txseq field in advance to use it after l2cap_reassemble_sdu
+	 * returns and to avoid the race condition, for example:
+	 *
+	 * The current thread calls:
+	 *   l2cap_reassemble_sdu
+	 *     chan->ops->recv == l2cap_sock_recv_cb
+	 *       __sock_queue_rcv_skb
+	 * Another thread calls:
+	 *   bt_sock_recvmsg
+	 *     skb_recv_datagram
+	 *     skb_free_datagram
+	 * Then the current thread tries to access control, but it was freed by
+	 * skb_free_datagram.
+	 */
+	u16 txseq = control->txseq;
+
 	BT_DBG("chan %p, control %p, skb %p, state %d", chan, control, skb,
 	       chan->rx_state);
 
-	if (l2cap_classify_txseq(chan, control->txseq) ==
-	    L2CAP_TXSEQ_EXPECTED) {
+	if (l2cap_classify_txseq(chan, txseq) == L2CAP_TXSEQ_EXPECTED) {
 		l2cap_pass_to_tx(chan, control);
 
 		BT_DBG("buffer_seq %u->%u", chan->buffer_seq,
@@ -7324,8 +7384,8 @@ static int l2cap_stream_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,
 		}
 	}
 
-	chan->last_acked_seq = control->txseq;
-	chan->expected_tx_seq = __next_seq(chan, control->txseq);
+	chan->last_acked_seq = txseq;
+	chan->expected_tx_seq = __next_seq(chan, txseq);
 
 	return 0;
 }
@@ -7581,6 +7641,7 @@ static void l2cap_data_channel(struct l2cap_conn *conn, u16 cid,
 				return;
 			}
 
+			l2cap_chan_hold(chan);
 			l2cap_chan_lock(chan);
 		} else {
 			BT_DBG("unknown cid 0x%4.4x", cid);
@@ -8426,9 +8487,8 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 		 * expected length.
 		 */
 		if (skb->len < L2CAP_LEN_SIZE) {
-			if (l2cap_recv_frag(conn, skb, conn->mtu) < 0)
-				goto drop;
-			return;
+			l2cap_recv_frag(conn, skb, conn->mtu);
+			break;
 		}
 
 		len = get_unaligned_le16(skb->data) + L2CAP_HDR_SIZE;
@@ -8472,7 +8532,7 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 
 			/* Header still could not be read just continue */
 			if (conn->rx_skb->len < L2CAP_LEN_SIZE)
-				return;
+				break;
 		}
 
 		if (skb->len > conn->rx_len) {