diff --git a/sys/dev/iscsi/iscsi.h b/sys/dev/iscsi/iscsi.h
--- a/sys/dev/iscsi/iscsi.h
+++ b/sys/dev/iscsi/iscsi.h
@@ -132,6 +132,7 @@
 	TAILQ_HEAD(, iscsi_session)	sc_sessions;
 	struct cv			sc_cv;
 	unsigned int			sc_last_session_id;
+	bool				sc_unloading;
 	eventhandler_tag		sc_shutdown_pre_eh;
 	eventhandler_tag		sc_shutdown_post_eh;
 };
diff --git a/sys/dev/iscsi/iscsi.c b/sys/dev/iscsi/iscsi.c
--- a/sys/dev/iscsi/iscsi.c
+++ b/sys/dev/iscsi/iscsi.c
@@ -1333,6 +1333,11 @@
 		}
 
 		if (is == NULL) {
+			if (sc->sc_unloading) {
+				sx_sunlock(&sc->sc_lock);
+				return (ENXIO);
+			}
+
 			/*
 			 * No session requires attention from iscsid(8); wait.
 			 */
@@ -2560,6 +2565,12 @@
 iscsi_unload(void)
 {
 
+	/* Awaken any threads asleep in iscsi_ioctl(). */
+	sx_xlock(&sc->sc_lock);
+	sc->sc_unloading = true;
+	cv_signal(&sc->sc_cv);
+	sx_xunlock(&sc->sc_lock);
+
 	if (sc->sc_cdev != NULL) {
 		ISCSI_DEBUG("removing device node");
 		destroy_dev(sc->sc_cdev);