diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -3537,8 +3537,10 @@
 int
 bus_generic_resume_child(device_t dev, device_t child)
 {
-	DEVICE_RESUME(child);
-	child->flags &= ~DF_SUSPENDED;
+	if (child->flags & DF_SUSPENDED) {
+		DEVICE_RESUME(child);
+		child->flags &= ~DF_SUSPENDED;
+	}
 
 	return (0);
 }
@@ -3566,6 +3568,8 @@
 	 * safer to bring down devices in the reverse order.
 	 */
 	TAILQ_FOREACH_REVERSE(child, &dev->children, device_list, link) {
+		if (!device_is_attached(child))
+			continue;
 		error = BUS_SUSPEND_CHILD(dev, child);
 		if (error != 0) {
 			child = TAILQ_NEXT(child, link);