2 files changed, 49 insertions, 11 deletions

diff --git a/mm/interval_tree.c b/mm/interval_tree.c
index f7c72cd35e1d..4a5822a586e6 100644
--- a/mm/interval_tree.c
+++ b/mm/interval_tree.c
@@ -70,4 +70,43 @@ static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
 }
 
 INTERVAL_TREE_DEFINE(struct anon_vma_chain, rb, unsigned long, rb_subtree_last,
-		     avc_start_pgoff, avc_last_pgoff,, anon_vma_interval_tree)
+		     avc_start_pgoff, avc_last_pgoff,
+		     static inline, __anon_vma_interval_tree)
+
+void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
+				   struct rb_root *root)
+{
+#ifdef CONFIG_DEBUG_VM_RB
+	node->cached_vma_start = avc_start_pgoff(node);
+	node->cached_vma_last = avc_last_pgoff(node);
+#endif
+	__anon_vma_interval_tree_insert(node, root);
+}
+
+void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
+				   struct rb_root *root)
+{
+	__anon_vma_interval_tree_remove(node, root);
+}
+
+struct anon_vma_chain *
+anon_vma_interval_tree_iter_first(struct rb_root *root,
+				  unsigned long first, unsigned long last)
+{
+	return __anon_vma_interval_tree_iter_first(root, first, last);
+}
+
+struct anon_vma_chain *
+anon_vma_interval_tree_iter_next(struct anon_vma_chain *node,
+				 unsigned long first, unsigned long last)
+{
+	return __anon_vma_interval_tree_iter_next(node, first, last);
+}
+
+#ifdef CONFIG_DEBUG_VM_RB
+void anon_vma_interval_tree_verify(struct anon_vma_chain *node)
+{
+	WARN_ON_ONCE(node->cached_vma_start != avc_start_pgoff(node));
+	WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node));
+}
+#endif
diff --git a/mm/mmap.c b/mm/mmap.c
index 2e580ed79211..deb422c39e21 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -51,12 +51,6 @@ static void unmap_region(struct mm_struct *mm,
 		struct vm_area_struct *vma, struct vm_area_struct *prev,
 		unsigned long start, unsigned long end);
 
-/*
- * WARNING: the debugging will use recursive algorithms so never enable this
- * unless you know what you are doing.
- */
-#undef DEBUG_MM_RB
-
 /* description of effects of mapping type and prot in current implementation.
  * this is due to the limited x86 page protection hardware.  The expected
  * behavior is in parens:
@@ -303,7 +297,7 @@ out:
 	return retval;
 }
 
-#ifdef DEBUG_MM_RB
+#ifdef CONFIG_DEBUG_VM_RB
 static int browse_rb(struct rb_root *root)
 {
 	int i = 0, j;
@@ -337,9 +331,12 @@ void validate_mm(struct mm_struct *mm)
 {
 	int bug = 0;
 	int i = 0;
-	struct vm_area_struct *tmp = mm->mmap;
-	while (tmp) {
-		tmp = tmp->vm_next;
+	struct vm_area_struct *vma = mm->mmap;
+	while (vma) {
+		struct anon_vma_chain *avc;
+		list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
+			anon_vma_interval_tree_verify(avc);
+		vma = vma->vm_next;
 		i++;
 	}
 	if (i != mm->map_count)
@@ -1790,6 +1787,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 	}
 	vma_unlock_anon_vma(vma);
 	khugepaged_enter_vma_merge(vma);
+	validate_mm(vma->vm_mm);
 	return error;
 }
 #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
@@ -1843,6 +1841,7 @@ int expand_downwards(struct vm_area_struct *vma,
 	}
 	vma_unlock_anon_vma(vma);
 	khugepaged_enter_vma_merge(vma);
+	validate_mm(vma->vm_mm);
 	return error;
 }