# blocked: stock module cannot construct (kfree(NULL) ctor panic, DF-3506);
# on the ctor-repaired harness module, rmnode deterministically panics first:
panic: assertion "IS_SERIALIZED((s))" failed in lwkt_serialize_exit
 lwkt_serialize_exit() ... ng_fec_stop() ... ng_fec_rmnode()
# so the tick-in-flight window is never entered on an INVARIANTS kernel;
# production kernels run the teardown and the callout race stands by code