Index: sys/vm/vm_map.c
===================================================================
--- sys/vm/vm_map.c
+++ sys/vm/vm_map.c
@@ -1496,7 +1496,7 @@
 	    vm_size_t length, vm_offset_t max_addr, int find_space,
 	    vm_prot_t prot, vm_prot_t max, int cow)
 {
-	vm_offset_t alignment, initial_addr, start;
+	vm_offset_t alignment, initial_addr, prev_start, start;
 	int result;
 
 	KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 ||
@@ -1512,6 +1512,7 @@
 		alignment = 0;
 	initial_addr = *addr;
 again:
+	result = KERN_SUCCESS;
 	start = initial_addr;
 	vm_map_lock(map);
 	do {
@@ -1543,6 +1544,8 @@
 
 			start = *addr;
 		}
+		if (result != KERN_SUCCESS && prev_start == start)
+			break;
 		if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) {
 			result = vm_map_stack_locked(map, start, length,
 			    sgrowsiz, prot, max, cow);
@@ -1550,6 +1553,7 @@
 			result = vm_map_insert(map, object, offset, start,
 			    start + length, prot, max, cow);
 		}
+		prev_start = start;
 	} while (result == KERN_NO_SPACE && find_space != VMFS_NO_SPACE &&
 	    find_space != VMFS_ANY_SPACE);
 	vm_map_unlock(map);