Index: sys/net/bridgestp.c
===================================================================
--- sys/net/bridgestp.c
+++ sys/net/bridgestp.c
@@ -154,6 +154,8 @@
 static void
 bstp_transmit(struct bstp_state *bs, struct bstp_port *bp)
 {
+	NET_EPOCH_ASSERT();
+
 	if (bs->bs_running == 0)
 		return;
 
@@ -346,6 +348,7 @@
 	struct ether_header *eh;
 
 	BSTP_LOCK_ASSERT(bs);
+	NET_EPOCH_ASSERT();
 
 	ifp = bp->bp_ifp;
 
@@ -923,6 +926,8 @@
 static void
 bstp_update_roles(struct bstp_state *bs, struct bstp_port *bp)
 {
+	NET_EPOCH_ASSERT();
+
 	switch (bp->bp_role) {
 	case BSTP_ROLE_DISABLED:
 		/* Clear any flags if set */
@@ -1862,6 +1867,7 @@
 static void
 bstp_tick(void *arg)
 {
+	struct epoch_tracker et;
 	struct bstp_state *bs = arg;
 	struct bstp_port *bp;
 
@@ -1870,6 +1876,7 @@
 	if (bs->bs_running == 0)
 		return;
 
+	NET_EPOCH_ENTER(et);
 	CURVNET_SET(bs->bs_vnet);
 
 	/* poll link events on interfaces that do not support linkstate */
@@ -1908,6 +1915,7 @@
 	}
 
 	CURVNET_RESTORE();
+	NET_EPOCH_EXIT(et);
 
 	callout_reset(&bs->bs_bstpcallout, hz, bstp_tick, bs);
 }
@@ -2229,6 +2237,7 @@
 	struct ifnet *ifp = bp->bp_ifp;
 
 	KASSERT(bp->bp_active == 0, ("already a bstp member"));
+	NET_EPOCH_ASSERT(); /* Because bstp_update_roles() causes traffic. */
 
 	switch (ifp->if_type) {
 		case IFT_ETHER:	/* These can do spanning tree. */
Index: sys/net/if_bridge.c
===================================================================
--- sys/net/if_bridge.c
+++ sys/net/if_bridge.c
@@ -1326,6 +1326,7 @@
 static int
 bridge_ioctl_sifflags(struct bridge_softc *sc, void *arg)
 {
+	struct epoch_tracker et;
 	struct ifbreq *req = arg;
 	struct bridge_iflist *bif;
 	struct bstp_port *bp;
@@ -1340,11 +1341,15 @@
 		/* SPAN is readonly */
 		return (EINVAL);
 
+	NET_EPOCH_ENTER(et);
+
 	if (req->ifbr_ifsflags & IFBIF_STP) {
 		if ((bif->bif_flags & IFBIF_STP) == 0) {
 			error = bstp_enable(&bif->bif_stp);
-			if (error)
+			if (error) {
+				NET_EPOCH_EXIT(et);
 				return (error);
+			}
 		}
 	} else {
 		if ((bif->bif_flags & IFBIF_STP) != 0)
@@ -1360,6 +1365,8 @@
 	/* Save the bits relating to the bridge */
 	bif->bif_flags = req->ifbr_ifsflags & IFBIFMASK;
 
+	NET_EPOCH_EXIT(et);
+
 	return (0);
 }