diff --git a/sys/dev/rtwn/if_rtwn_tx.c b/sys/dev/rtwn/if_rtwn_tx.c
--- a/sys/dev/rtwn/if_rtwn_tx.c
+++ b/sys/dev/rtwn/if_rtwn_tx.c
@@ -263,6 +263,12 @@
 	struct mbuf *m;
 
 	RTWN_ASSERT_LOCKED(sc);
+
+	/* Ensure no work is scheduled during reset/teardown */
+	if ((sc->sc_flags & RTWN_RUNNING) == 0) {
+		return;
+	}
+
 	while ((m = mbufq_dequeue(&sc->sc_snd)) != NULL) {
 		if (sc->qfullmsk != 0) {
 			mbufq_prepend(&sc->sc_snd, m);