Index: sys/kern/kern_conf.c
===================================================================
--- sys/kern/kern_conf.c
+++ sys/kern/kern_conf.c
@@ -1437,6 +1437,7 @@
 	struct cdev *dev;
 	void (*cb)(void *);
 	void *cb_arg;
+	bool need_giant;
 
 	dev_lock();
 	while (!TAILQ_EMPTY(&dev_ddtr)) {
@@ -1447,11 +1448,17 @@
 		TAILQ_REMOVE(&dev_ddtr, cp, cdp_dtr_list);
 		cb = cp->cdp_dtr_cb;
 		cb_arg = cp->cdp_dtr_cb_arg;
+		need_giant = (dev->si_devsw->d_flags & D_NEEDGIANT) != 0;
 		destroy_devl(dev);
 		dev_unlock_and_free();
 		dev_rel(dev);
-		if (cb != NULL)
+		if (cb != NULL) {
+			if (need_giant)
+				mtx_lock(&Giant);
 			cb(cb_arg);
+			if (need_giant)
+				mtx_unlock(&Giant);
+		}
 		dev_lock();
 	}
 	dev_unlock();
@@ -1478,7 +1485,7 @@
 	cp->cdp_dtr_cb_arg = arg;
 	TAILQ_INSERT_TAIL(&dev_ddtr, cp, cdp_dtr_list);
 	dev_unlock();
-	taskqueue_enqueue(taskqueue_swi_giant, &dev_dtr_task);
+	taskqueue_enqueue(taskqueue_thread, &dev_dtr_task);
 	return (1);
 }