Index: sys/kern/kern_event.c
===================================================================
--- sys/kern/kern_event.c
+++ sys/kern/kern_event.c
@@ -600,10 +600,10 @@
 			kn->kn_fflags |= NOTE_TRACKERR;
 		if (kn->kn_fop->f_event(kn, NOTE_FORK))
 			KNOTE_ACTIVATE(kn, 0);
+		list->kl_lock(list->kl_lockarg);
 		KQ_LOCK(kq);
 		kn_leave_flux(kn);
 		KQ_UNLOCK_FLUX(kq);
-		list->kl_lock(list->kl_lockarg);
 	}
 	list->kl_unlock(list->kl_lockarg);
 }
@@ -1460,8 +1460,11 @@
 					break;
 		}
 	} else {
-		if ((kev->flags & EV_ADD) == EV_ADD)
-			kqueue_expand(kq, fops, kev->ident, waitok);
+		if ((kev->flags & EV_ADD) == EV_ADD) {
+			error = kqueue_expand(kq, fops, kev->ident, waitok);
+			if (error != 0)
+				goto done;
+		}
 
 		KQ_LOCK(kq);
 
@@ -1697,12 +1700,12 @@
 {
 	struct klist *list, *tmp_knhash, *to_free;
 	u_long tmp_knhashmask;
-	int size;
-	int fd;
+	int error, fd, size;
 	int mflag = waitok ? M_WAITOK : M_NOWAIT;
 
 	KQ_NOTOWNED(kq);
 
+	error = 0;
 	to_free = NULL;
 	if (fops->f_isfd) {
 		fd = ident;
@@ -1714,9 +1717,11 @@
 			if (list == NULL)
 				return ENOMEM;
 			KQ_LOCK(kq);
-			if (kq->kq_knlistsize > fd) {
+			if ((kq->kq_state & KQ_CLOSING) != 0) {
+				to_free = list;
+				error = EBADF;
+			} else if (kq->kq_knlistsize > fd) {
 				to_free = list;
-				list = NULL;
 			} else {
 				if (kq->kq_knlist != NULL) {
 					bcopy(kq->kq_knlist, list,
@@ -1737,9 +1742,12 @@
 			tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
 			    &tmp_knhashmask);
 			if (tmp_knhash == NULL)
-				return ENOMEM;
+				return (ENOMEM);
 			KQ_LOCK(kq);
-			if (kq->kq_knhashmask == 0) {
+			if ((kq->kq_state & KQ_CLOSING) != 0) {
+				to_free = tmp_knhash;
+				error = EBADF;
+			} else if (kq->kq_knhashmask == 0) {
 				kq->kq_knhash = tmp_knhash;
 				kq->kq_knhashmask = tmp_knhashmask;
 			} else {
@@ -1751,7 +1759,7 @@
 	free(to_free, M_KQUEUE);
 
 	KQ_NOTOWNED(kq);
-	return 0;
+	return (error);
 }
 
 static void
@@ -2600,6 +2608,8 @@
 	KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn));
 	KQ_OWNED(kq);
 
+	if ((kq->kq_state & KQ_CLOSING) != 0)
+		return (EBADF);
 	if (kn->kn_fop->f_isfd) {
 		if (kn->kn_id >= kq->kq_knlistsize)
 			return (ENOMEM);