{
lockdep_assert_held(q->queue_lock);
+ /*
+ * @q could be exiting and already have destroyed all blkgs as
+ * indicated by NULL root_blkg. If so, don't confuse policies.
+ */
+ if (!q->root_blkg)
+ return;
+
/*
* @q could be exiting and already have destroyed all blkgs as
* indicated by NULL root_blkg. If so, don't confuse policies.