diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 2fe8c60dc62bc9e53d92713b35a1315119703f5c..6e71aa6b6feae15931e14204200301dcd893cf61 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -382,6 +382,9 @@ int hci_cmd_sync_queue(struct hci_dev *hdev, hci_cmd_sync_work_func_t func,
 {
 	struct hci_cmd_sync_work_entry *entry;
 
+	if (hci_dev_test_flag(hdev, HCI_UNREGISTER))
+		return -ENODEV;
+
 	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry)
 		return -ENOMEM;