--- xnu/xnu-8792.61.2/libkern/c++/priority_queue.cpp
+++ xnu/xnu-8019.41.5/libkern/c++/priority_queue.cpp
@@ -236,12 +236,6 @@
 	}
 
 	static inline void
-	list_clear(entry_t e)
-	{
-		e->next = e->prev = NULL;
-	}
-
-	static inline void
 	list_remove(entry_t elt)
 	{
 		assert(elt->prev != NULL);
@@ -257,31 +251,13 @@
 		if (elt->next != NULL) {
 			elt->next->prev = elt->prev;
 		}
-		list_clear(elt);
 	}
 
 	static inline bool
 	sift_down(queue_t que, entry_t elt)
 	{
-		bool was_root = (que->pq_root == elt);
-
-		if (!was_root) {
-			remove_non_root(que, elt);
-			insert(que, elt, false);
-		} else if (unpack_child(elt)) {
-			remove_root(que, elt);
-			insert(que, elt, false);
-		} else {
-			/*
-			 * If the queue is reduced to a single element,
-			 * we have nothing to do.
-			 *
-			 * It is important not to, so that pq_root remains
-			 * non null at all times during priority changes,
-			 * so that unsynchronized peeking at the "emptiness"
-			 * of the priority queue works as expected.
-			 */
-		}
+		bool was_root = remove(que, elt);
+		insert(que, elt);
 		return was_root;
 	}
 
@@ -295,7 +271,7 @@
 		/* Remove the element from its current level list */
 		list_remove(elt);
 		/* Re-insert the element into the heap with a merge */
-		return insert(que, elt, false);
+		return insert(que, elt);
 	}
 
 	static inline entry_t
@@ -315,7 +291,6 @@
 			child = meld_pair(que, child);
 			new_root = merge_pair(que, que->pq_root, child);
 			que->pq_root = new_root;
-			pack_child(elt, nullptr);
 		}
 
 		return elt;
@@ -354,12 +329,8 @@
 	}
 
 	static inline bool
-	insert(queue_t que, entry_t elt, bool clear = true)
-	{
-		if (clear) {
-			list_clear(elt);
-			pack_child(elt, nullptr);
-		}
+	insert(queue_t que, entry_t elt)
+	{
 		return (que->pq_root = merge_pair(que, que->pq_root, elt)) == elt;
 	}
 
@@ -367,13 +338,7 @@
 	remove_root(queue_t que, entry_t old_root)
 	{
 		entry_t new_root = unpack_child(old_root);
-
-		if (new_root) {
-			que->pq_root = meld_pair(que, new_root);
-			pack_child(old_root, nullptr);
-		} else {
-			que->pq_root = NULL;
-		}
+		que->pq_root = new_root ? meld_pair(que, new_root) : NULL;
 		return old_root;
 	}
 
@@ -382,9 +347,19 @@
 	{
 		if (elt == que->pq_root) {
 			remove_root(que, elt);
+			elt->next = elt->prev = NULL;
+			elt->child = 0;
+#if CONFIG_KERNEL_TBI && KASAN_TBI
+			elt->tag = 0;
+#endif /* CONFIG_KERNEL_TBI && KASAN_TBI */
 			return true;
 		} else {
 			remove_non_root(que, elt);
+			elt->next = elt->prev = NULL;
+			elt->child = 0;
+#if CONFIG_KERNEL_TBI && KASAN_TBI
+			elt->tag = 0;
+#endif
 			return false;
 		}
 	}