f6d8983846
vm_object_backing_scan() was not written to handle. Specifically, a wired page within a backing object that is shadowed by a page within the shadow object. Handle this state by removing the wired page from the backing object. The wired page will be freed by socow_iodone(). Stop masking errors: If a page is being freed by vm_object_backing_scan(), assert that it is no longer mapped rather than quietly destroying any mappings. Tested by: Harald Schmalzbauer