diff --git a/sys/dev/cxgbe/adapter.h b/sys/dev/cxgbe/adapter.h
index 4d24d68722db..ceba9e03ddad 100644
--- a/sys/dev/cxgbe/adapter.h
+++ b/sys/dev/cxgbe/adapter.h
@@ -801,6 +801,7 @@ struct adapter {
 #ifdef INVARIANTS
 	const char *last_op;
 	const void *last_op_thr;
+	int last_op_flags;
 #endif
 
 	int sc_do_rxcopy;
diff --git a/sys/dev/cxgbe/t4_main.c b/sys/dev/cxgbe/t4_main.c
index 571b3e0a303a..22a533309ad4 100644
--- a/sys/dev/cxgbe/t4_main.c
+++ b/sys/dev/cxgbe/t4_main.c
@@ -1149,6 +1149,7 @@ cxgbe_detach(device_t dev)
 #ifdef INVARIANTS
 	sc->last_op = "t4detach";
 	sc->last_op_thr = curthread;
+	sc->last_op_flags = 0;
 #endif
 	ADAPTER_UNLOCK(sc);
 
@@ -3109,6 +3110,7 @@ begin_synchronized_op(struct adapter *sc, struct port_info *pi, int flags,
 #ifdef INVARIANTS
 	sc->last_op = wmesg;
 	sc->last_op_thr = curthread;
+	sc->last_op_flags = flags;
 #endif
 
 done: