diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index f886c1d05c88..f614f96c5c23 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -643,6 +643,7 @@ void hci_cmd_sync_clear(struct hci_dev *hdev)
 	cancel_work_sync(&hdev->cmd_sync_work);
 	cancel_work_sync(&hdev->reenable_adv_work);
 
+	mutex_lock(&hdev->cmd_sync_work_lock);
 	list_for_each_entry_safe(entry, tmp, &hdev->cmd_sync_work_list, list) {
 		if (entry->destroy)
 			entry->destroy(hdev, entry->data, -ECANCELED);
@@ -650,6 +651,7 @@ void hci_cmd_sync_clear(struct hci_dev *hdev)
 		list_del(&entry->list);
 		kfree(entry);
 	}
+	mutex_unlock(&hdev->cmd_sync_work_lock);
 }
 
 void __hci_cmd_sync_cancel(struct hci_dev *hdev, int err)