diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -1851,9 +1851,6 @@
 	VM_OBJECT_ASSERT_WLOCKED(new_object);
 
 	KASSERT(m->ref_count != 0, ("vm_page_rename: page %p has no refs", m));
-	mpred = vm_radix_lookup_le(&new_object->rtree, new_pindex);
-	KASSERT(mpred == NULL || mpred->pindex != new_pindex,
-	    ("vm_page_rename: pindex already renamed"));
 
 	/*
 	 * Create a custom version of vm_page_insert() which does not depend
@@ -1862,7 +1859,7 @@
 	 */
 	opidx = m->pindex;
 	m->pindex = new_pindex;
-	if (vm_radix_insert(&new_object->rtree, m)) {
+	if (vm_radix_insert_lookup_lt(&new_object->rtree, m, &mpred) != 0) {
 		m->pindex = opidx;
 		return (1);
 	}
diff --git a/sys/vm/vm_radix.h b/sys/vm/vm_radix.h
--- a/sys/vm/vm_radix.h
+++ b/sys/vm/vm_radix.h
@@ -69,6 +69,26 @@
 	return (VM_RADIX_PCTRIE_INSERT(&rtree->rt_trie, page));
 }
 
+/*
+ * Insert the page into the vm_radix tree with its pindex as the key.  Panic if
+ * the pindex already exists.  Return zero on success or a non-zero error on
+ * memory allocation failure.  Set the out parameter mpred to the previous page
+ * in the tree as if found by a previous call to vm_radix_lookup_le with the
+ * new page pindex.
+ */
+static __inline int
+vm_radix_insert_lookup_lt(struct vm_radix *rtree, vm_page_t page,
+    vm_page_t *mpred)
+{
+	int error;
+
+	error = VM_RADIX_PCTRIE_INSERT_LOOKUP_LE(&rtree->rt_trie, page, mpred);
+	if (__predict_false(error == EEXIST))
+		panic("vm_radix_insert_lookup_lt: page already present, %p",
+		    *mpred);
+	return (error);
+}
+
 /*
  * Returns the value stored at the index assuming there is an external lock.
  *