--- //depot/projects/netperf_socket/sys/net/if_tun.c	2004/02/28 09:51:12
+++ //depot/user/rwatson/netperf/sys/net/if_tun.c	2004/03/06 20:55:10
@@ -81,6 +81,15 @@
 #define TUNDEBUG	if (tundebug) if_printf
 #define	TUNNAME		"tun"
 
+/*
+ * All mutable global variables in if_tun are locked using tunmtx, with
+ * the exception of tundebug, which is used unlocked.  Per-softc data
+ * not yet locked.
+ *
+ * XXXRW: tunclones can't be properly locked with the current API.  Bug
+ * phk about this.
+ */
+static struct mtx tunmtx;
 static MALLOC_DEFINE(M_TUN, TUNNAME, "Tunnel Interface");
 static int tundebug = 0;
 static struct clonedevs *tunclones;
@@ -150,6 +159,7 @@
 
 	switch (type) {
 	case MOD_LOAD:
+		mtx_init(&tunmtx, "tunmtx", NULL, MTX_DEF);
 		tag = EVENTHANDLER_REGISTER(dev_clone, tunclone, 0, 1000);
 		if (tag == NULL)
 			return (ENOMEM);
@@ -157,19 +167,25 @@
 	case MOD_UNLOAD:
 		EVENTHANDLER_DEREGISTER(dev_clone, tag);
 
-		while (!TAILQ_EMPTY(&tunhead)) {
-			tp = TAILQ_FIRST(&tunhead);
+		mtx_lock(&tunmtx);
+		while ((tp = TAILQ_FIRST(&tunhead)) != NULL) {
+			TAILQ_REMOVE(&tunhead, tp, tun_list);
+			mtx_unlock(&tunmtx);
+
 			KASSERT((tp->tun_flags & TUN_OPEN) == 0,
 			    ("tununits is out of sync - unit %d",
 			    tp->tun_if.if_dunit));
-			TAILQ_REMOVE(&tunhead, tp, tun_list);
+
 			dev = tp->tun_dev;
 			bpfdetach(&tp->tun_if);
 			if_detach(&tp->tun_if);
 			destroy_dev(dev);
 			free(tp, M_TUN);
+			mtx_lock(&tunmtx);
 		}
+		mtx_unlock(&tunmtx);
 		clone_cleanup(&tunclones);
+		mtx_destroy(&tunmtx);
 		break;
 	}
 	return 0;
@@ -208,7 +224,9 @@
 	MALLOC(sc, struct tun_softc *, sizeof(*sc), M_TUN, M_WAITOK | M_ZERO);
 	sc->tun_flags = TUN_INITED;
 	sc->tun_dev = dev;
+	mtx_lock(&tunmtx);
 	TAILQ_INSERT_TAIL(&tunhead, sc, tun_list);
+	mtx_unlock(&tunmtx);
 
 	ifp = &sc->tun_if;
 	if_initname(ifp, TUNNAME, dev2unit(dev));