1 files changed, 10 insertions, 2 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index 09ce2ca..da15a79 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1608,7 +1608,6 @@ EXPORT_SYMBOL(find_vma);
 
 /*
  * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
- * Note: pprev is set to NULL when return value is NULL.
  */
 struct vm_area_struct *
 find_vma_prev(struct mm_struct *mm, unsigned long addr,
@@ -1617,7 +1616,16 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr,
 	struct vm_area_struct *vma;
 
 	vma = find_vma(mm, addr);
-	*pprev = vma ? vma->vm_prev : NULL;
+	if (vma) {
+		*pprev = vma->vm_prev;
+	} else {
+		struct rb_node *rb_node = mm->mm_rb.rb_node;
+		*pprev = NULL;
+		while (rb_node) {
+			*pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb);
+			rb_node = rb_node->rb_right;
+		}
+	}
 	return vma;
 }