diff --git a/kernel-lib/rbtree.h b/kernel-lib/rbtree.h
index 87b67125..508edee0 100644
--- a/kernel-lib/rbtree.h
+++ b/kernel-lib/rbtree.h
@@ -19,11 +19,11 @@
   linux/include/linux/rbtree.h
 
   To use rbtrees you'll have to implement your own insert and search cores.
-  This will avoid us to use callbacks and to drop dramatically performances.
+  This will avoid us to use callbacks and to drop drammatically performances.
   I know it's not the cleaner way,  but in C (not in C++) to get
   performances and genericity...
 
-  See Documentation/rbtree.txt for documentation and samples.
+  See Documentation/core-api/rbtree.rst for documentation and samples.
 */
 
 #ifndef	_LINUX_RBTREE_H
@@ -47,9 +47,9 @@ extern "C" {
 
 #define	rb_entry(ptr, type, member) container_of(ptr, type, member)
 
-#define RB_EMPTY_ROOT(root)  ((root)->rb_node == NULL)
+#define RB_EMPTY_ROOT(root)  (READ_ONCE((root)->rb_node) == NULL)
 
-/* 'empty' nodes are nodes that are known not to be inserted in an rtbree */
+/* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
 #define RB_EMPTY_NODE(node)  \
 	((node)->__rb_parent_color == (unsigned long)(node))
 #define RB_CLEAR_NODE(node)  \
@@ -74,8 +74,8 @@ extern struct rb_node *rb_next_postorder(const struct rb_node *);
 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new_node,
 			    struct rb_root *root);
 
-static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
-				struct rb_node ** rb_link)
+static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
+				struct rb_node **rb_link)
 {
 	node->__rb_parent_color = (unsigned long)parent;
 	node->rb_left = node->rb_right = NULL;
@@ -89,13 +89,21 @@ static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
 	})
 
 /**
- * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
- * given type safe against removal of rb_node entry
+ * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
+ * given type allowing the backing memory of @pos to be invalidated
  *
  * @pos:	the 'type *' to use as a loop cursor.
  * @n:		another 'type *' to use as temporary storage
  * @root:	'rb_root *' of the rbtree.
  * @field:	the name of the rb_node field within 'type'.
+ *
+ * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
+ * list_for_each_entry_safe() and allows the iteration to continue independent
+ * of changes to @pos by the body of the loop.
+ *
+ * Note, however, that it cannot handle other modifications that re-order the
+ * rbtree it is iterating over. This includes calling rb_erase() on @pos, as
+ * rb_erase() may rebalance the tree, causing us to miss some nodes.
  */
 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
 	for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \