Index: sys/vm/vm_map.c
===================================================================
--- sys/vm/vm_map.c
+++ sys/vm/vm_map.c
@@ -898,7 +898,7 @@
 {
 	vm_map_entry_t llist, rlist;
 	vm_map_entry_t ltree, rtree;
-	vm_map_entry_t y;
+	vm_map_entry_t y, z;
 
 	/* Special case of empty tree. */
 	if (root == NULL)
@@ -914,46 +914,74 @@
 	 */
 	llist = NULL;
 	rlist = NULL;
-	for (;;) {
+	for (;; root = z) {
 		/* root is never NULL in here. */
 		if (addr < root->start) {
 			y = root->left;
 			if (y == NULL)
 				break;
-			if (addr < y->start && y->left != NULL) {
-				/* Rotate right and put y on rlist. */
-				root->left = y->right;
-				y->right = root;
-				vm_map_entry_set_max_free(root);
-				root = y->left;
-				y->left = rlist;
-				rlist = y;
-			} else {
-				/* Put root on rlist. */
-				root->left = rlist;
-				rlist = root;
-				root = y;
+			if (addr < y->start) {
+				z = y->left;
+				if (z != NULL) {
+					/* Put y on rlist. */
+					y->left = rlist;
+					rlist = y;
+					/* Rotate right. */
+					root->left = y->right;
+					y->right = root;
+					vm_map_entry_set_max_free(root);
+					continue;
+				}
+			} else if (addr >= y->end) {
+				z = y->right;
+				if (z != NULL) {
+					/* Put y on llist. */
+					y->right = llist;
+					llist = y;
+					/* Put root on rlist. */
+					root->left = rlist;
+					rlist = root;
+					continue;
+				}
 			}
+			/* Put root on rlist. */
+			root->left = rlist;
+			rlist = root;
+			root = y;
 		} else if (addr >= root->end) {
 			y = root->right;
 			if (y == NULL)
 				break;
-			if (addr >= y->end && y->right != NULL) {
-				/* Rotate left and put y on llist. */
-				root->right = y->left;
-				y->left = root;
-				vm_map_entry_set_max_free(root);
-				root = y->right;
-				y->right = llist;
-				llist = y;
-			} else {
-				/* Put root on llist. */
-				root->right = llist;
-				llist = root;
-				root = y;
+			if (addr >= y->end) {
+				z = y->right;
+				if (z != NULL) {
+					/* Put y on llist. */
+					y->right = llist;
+					llist = y;
+					/* Rotate left. */
+					root->right = y->left;
+					y->left = root;
+					vm_map_entry_set_max_free(root);
+					continue;
+				}
+			} else if (addr < y->start) {
+				z = y->left;
+				if (z != NULL) {
+					/* Put y on rlist */
+					y->left = rlist;
+					rlist = y;
+					/* Put root on llist. */
+					root->right = llist;
+					llist = root;
+					continue;
+				}
 			}
-		} else
-			break;
+			/* Put root on llist. */
+			root->right = llist;
+			llist = root;
+			root = y;
+		}
+		break;
 	}
 
 	/*