Merge branch 'bluetooth' into bluetooth-next

2 files changed, 69 insertions, 23 deletions

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index f305213fa0f9..3fb8b5474948 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -48,8 +48,11 @@ static void rfcomm_sock_kill(struct sock *sk);
 static void rfcomm_sk_data_ready(struct rfcomm_dlc *d, struct sk_buff *skb)
 {
 	struct sock *sk = d->owner;
-	if (!sk)
+
+	if (!sk) {
+		kfree_skb(skb);
 		return;
+	}
 
 	atomic_add(skb->len, &sk->sk_rmem_alloc);
 	skb_queue_tail(&sk->sk_receive_queue, skb);
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index e19079b9c432..8be48ca9f4c5 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -84,12 +84,14 @@ static void sco_conn_free(struct kref *ref)
 	if (conn->sk)
 		sco_pi(conn->sk)->conn = NULL;
 
-	if (conn->hcon) {
-		conn->hcon->sco_data = NULL;
-		hci_conn_drop(conn->hcon);
-	}
+	/* hcon->sco_data is cleared and the association's reference on the
+	 * sco_conn is dropped in sco_conn_del() under hdev->lock, and the
+	 * hci_conn is now owned by the socket (held in __sco_chan_add() and
+	 * dropped in sco_chan_del()/sco_sock_destruct()), so there is nothing
+	 * left to release towards hcon here.
+	 */
 
-	/* Ensure no more work items will run since hci_conn has been dropped */
+	/* Ensure no more work items will run before the connection is freed */
 	disable_delayed_work_sync(&conn->timeout_work);
 
 	kfree(conn);
@@ -188,25 +190,19 @@ static void sco_sock_clear_timer(struct sock *sk)
 }
 
 /* ---- SCO connections ---- */
-/* Consumes a reference on @hcon, which the returned sco_conn owns until it is
- * freed. On failure (NULL return) the reference is left for the caller to drop.
+/* Returns a new reference the caller must drop with sco_conn_put(). The
+ * hcon->sco_data association holds its own reference on the sco_conn for the
+ * connection's lifetime; it is dropped in sco_conn_del() under hdev->lock.
+ * @hcon is not consumed: the hci_conn reference is taken and owned by the
+ * socket in __sco_chan_add().
  */
 static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
 {
 	struct sco_conn *conn = hcon->sco_data;
 
 	conn = sco_conn_hold_unless_zero(conn);
-	if (conn) {
-		if (!conn->hcon) {
-			sco_conn_lock(conn);
-			conn->hcon = hcon;
-			sco_conn_unlock(conn);
-		} else {
-			/* conn already owns a reference on hcon */
-			hci_conn_drop(hcon);
-		}
+	if (conn)
 		return conn;
-	}
 
 	conn = kzalloc_obj(struct sco_conn);
 	if (!conn)
@@ -227,7 +223,10 @@ static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
 
 	BT_DBG("hcon %p conn %p", hcon, conn);
 
-	return conn;
+	/* kref_init() above set the association reference owned by
+	 * hcon->sco_data; hand the caller its own reference.
+	 */
+	return sco_conn_hold(conn);
 }
 
 /* Delete channel.
@@ -242,6 +241,19 @@ static void sco_chan_del(struct sock *sk, int err)
 	BT_DBG("sk %p, conn %p, err %d", sk, conn, err);
 
 	if (conn) {
+		struct hci_conn *hcon;
+
+		sco_conn_lock(conn);
+		hcon = conn->hcon;
+		sco_conn_unlock(conn);
+
+		/* Drop the socket's hci_conn reference BEFORE clearing
+		 * conn->sk, so sco_conn_del() on another CPU cannot free
+		 * the hci_conn while we still hold a pointer to it.
+		 */
+		if (hcon)
+			hci_conn_drop(hcon);
+
 		sco_conn_lock(conn);
 		conn->sk = NULL;
 		sco_conn_unlock(conn);
@@ -266,6 +278,13 @@ static void sco_conn_del(struct hci_conn *hcon, int err)
 
 	BT_DBG("hcon %p conn %p, err %d", hcon, conn, err);
 
+	/* Detach from the hci_conn and drop the association's reference.
+	 * The caller holds hdev->lock, which serialises this against the
+	 * read of hcon->sco_data in sco_recv_scodata().
+	 */
+	hcon->sco_data = NULL;
+	sco_conn_put(conn);
+
 	sco_conn_lock(conn);
 	sk = sco_sock_hold(conn);
 	sco_conn_unlock(conn);
@@ -290,6 +309,11 @@ static void __sco_chan_add(struct sco_conn *conn, struct sock *sk,
 	sco_pi(sk)->conn = sco_conn_hold(conn);
 	conn->sk = sk;
 
+	/* The socket owns an hci_conn reference for as long as it stays
+	 * attached; it is dropped in sco_chan_del()/sco_sock_destruct().
+	 */
+	hci_conn_hold(conn->hcon);
+
 	if (parent)
 		bt_accept_enqueue(parent, sk, true);
 }
@@ -371,6 +395,7 @@ static int sco_connect(struct sock *sk)
 	if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND) {
 		release_sock(sk);
 		sco_conn_put(conn);
+		hci_conn_drop(hcon);
 		err = -EBADFD;
 		goto unlock;
 	}
@@ -379,9 +404,13 @@ static int sco_connect(struct sock *sk)
 	sco_conn_put(conn);
 	if (err) {
 		release_sock(sk);
+		hci_conn_drop(hcon);
 		goto unlock;
 	}
 
+	/* __sco_chan_add() took its own hci_conn reference; drop ours. */
+	hci_conn_drop(hcon);
+
 	/* Update source addr of the socket */
 	bacpy(&sco_pi(sk)->src, &hcon->src);
 
@@ -495,9 +524,25 @@ static struct sock *sco_get_sock_listen(bdaddr_t *src)
 
 static void sco_sock_destruct(struct sock *sk)
 {
+	struct sco_conn *conn = sco_pi(sk)->conn;
+
 	BT_DBG("sk %p", sk);
 
-	sco_conn_put(sco_pi(sk)->conn);
+	/* If the channel was not already torn down via sco_chan_del(), drop
+	 * the socket's own references here.
+	 */
+	if (conn) {
+		struct hci_conn *hcon;
+
+		sco_conn_lock(conn);
+		hcon = conn->hcon;
+		sco_conn_unlock(conn);
+
+		if (hcon)
+			hci_conn_drop(hcon);
+		sco_pi(sk)->conn = NULL;
+		sco_conn_put(conn);
+	}
 
 	skb_queue_purge(&sk->sk_receive_queue);
 	skb_queue_purge(&sk->sk_write_queue);
@@ -1505,12 +1550,10 @@ static void sco_connect_cfm(struct hci_conn *hcon, __u8 status)
 	if (!status) {
 		struct sco_conn *conn;
 
-		conn = sco_conn_add(hci_conn_hold(hcon));
+		conn = sco_conn_add(hcon);
 		if (conn) {
 			sco_conn_ready(conn);
 			sco_conn_put(conn);
-		} else {
-			hci_conn_drop(hcon);
 		}
 	} else
 		sco_conn_del(hcon, bt_to_errno(status));