diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index 98d3d1e5bb1..8d654f5ac61 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -4263,6 +4263,7 @@ vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
 	vm2->vm_taddr = vm1->vm_taddr;
 	vm2->vm_daddr = vm1->vm_daddr;
 	vm2->vm_maxsaddr = vm1->vm_maxsaddr;
+	vm2->vm_stacktop = vm1->vm_stacktop;
 	vm_map_lock(old_map);
 	if (old_map->busy)
 		vm_map_wait_busy(old_map);