Bluetooth: Fix memory leak in read_adv_mon_features()

read_adv_mon_features() is leaking memory. Free `rp` before returning.

Fixes: e5e1e7fd ("Bluetooth: Add handler of MGMT_OP_READ_ADV_MONITOR_FEATURES")
Reported-and-tested-by: syzbot+f7f6e564f4202d8601c6@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=f7f6e564f4202d8601c6Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/mgmt.c

@@ -4157,7 +4157,7 @@ static int read_adv_mon_features(struct sock *sk, struct hci_dev *hdev,
 {
 	struct adv_monitor *monitor = NULL;
 	struct mgmt_rp_read_adv_monitor_features *rp = NULL;
-	int handle;
+	int handle, err;
 	size_t rp_size = 0;
 	__u32 supported = 0;
 	__u16 num_handles = 0;
@@ -4192,9 +4192,13 @@ static int read_adv_mon_features(struct sock *sk, struct hci_dev *hdev,
 	if (num_handles)
 		memcpy(&rp->handles, &handles, (num_handles * sizeof(u16)));
 
-	return mgmt_cmd_complete(sk, hdev->id,
-				 MGMT_OP_READ_ADV_MONITOR_FEATURES,
-				 MGMT_STATUS_SUCCESS, rp, rp_size);
+	err = mgmt_cmd_complete(sk, hdev->id,
+				MGMT_OP_READ_ADV_MONITOR_FEATURES,
+				MGMT_STATUS_SUCCESS, rp, rp_size);
+
+	kfree(rp);
+
+	return err;
 }
 
 static int add_adv_patterns_monitor(struct sock *sk, struct hci_dev *hdev,