diff --git a/sys/netinet6/ip6_mroute.c b/sys/netinet6/ip6_mroute.c
--- a/sys/netinet6/ip6_mroute.c
+++ b/sys/netinet6/ip6_mroute.c
@@ -167,16 +167,13 @@
 #define NO_RTE_FOUND	0x1
 #define RTE_FOUND	0x2
 
-static struct mtx mrouter6_mtx;
-#define	MROUTER6_LOCK()		mtx_lock(&mrouter6_mtx)
-#define	MROUTER6_UNLOCK()	mtx_unlock(&mrouter6_mtx)
-#define	MROUTER6_LOCK_ASSERT()	do {					\
-	mtx_assert(&mrouter6_mtx, MA_OWNED);				\
-	NET_ASSERT_GIANT();						\
-} while (0)
-#define	MROUTER6_LOCK_INIT()	\
-	mtx_init(&mrouter6_mtx, "IPv6 multicast forwarding", NULL, MTX_DEF)
-#define	MROUTER6_LOCK_DESTROY()	mtx_destroy(&mrouter6_mtx)
+static struct sx mrouter6_mtx;
+#define	MROUTER6_LOCKPTR()	(&mrouter6_mtx)
+#define	MROUTER6_LOCK()		sx_xlock(MROUTER6_LOCKPTR())
+#define	MROUTER6_UNLOCK()	sx_xunlock(MROUTER6_LOCKPTR())
+#define	MROUTER6_LOCK_ASSERT()	sx_assert(MROUTER6_LOCKPTR(), SA_XLOCKED
+#define	MROUTER6_LOCK_INIT()	sx_init(MROUTER6_LOCKPTR(), "mrouter6")
+#define	MROUTER6_LOCK_DESTROY()	sx_destroy(MROUTER6_LOCKPTR())
 
 static struct mf6c *mf6ctable[MF6CTBLSIZ];
 SYSCTL_OPAQUE(_net_inet6_ip6, OID_AUTO, mf6ctable, CTLFLAG_RD,
@@ -185,15 +182,14 @@
     "netinet6/ip6_mroute.h)");
 
 static struct mtx mfc6_mtx;
-#define	MFC6_LOCK()		mtx_lock(&mfc6_mtx)
-#define	MFC6_UNLOCK()		mtx_unlock(&mfc6_mtx)
-#define	MFC6_LOCK_ASSERT()	do {					\
-	mtx_assert(&mfc6_mtx, MA_OWNED);				\
-	NET_ASSERT_GIANT();						\
-} while (0)
-#define	MFC6_LOCK_INIT()		\
-	mtx_init(&mfc6_mtx, "IPv6 multicast forwarding cache", NULL, MTX_DEF)
-#define	MFC6_LOCK_DESTROY()	mtx_destroy(&mfc6_mtx)
+#define	MFC6_LOCKPTR()		(&mfc6_mtx)
+#define	MFC6_LOCK()		mtx_lock(MFC6_LOCKPTR())
+#define	MFC6_UNLOCK()		mtx_unlock(MFC6_LOCKPTR())
+#define	MFC6_LOCK_ASSERT()	mtx_assert(MFC6_LOCKPTR(), MA_OWNED)
+#define	MFC6_LOCK_INIT()	mtx_init(MFC6_LOCKPTR(),		\
+				    "IPv6 multicast forwarding cache",	\
+				    NULL, MTX_DEF)
+#define	MFC6_LOCK_DESTROY()	mtx_destroy(MFC6_LOCKPTR())
 
 static u_char n6expire[MF6CTBLSIZ];
 
@@ -230,12 +226,13 @@
     "netinet6/ip6_mroute.h)");
 
 static struct mtx mif6_mtx;
-#define	MIF6_LOCK()		mtx_lock(&mif6_mtx)
-#define	MIF6_UNLOCK()		mtx_unlock(&mif6_mtx)
-#define	MIF6_LOCK_ASSERT()	mtx_assert(&mif6_mtx, MA_OWNED)
+#define	MIF6_LOCKPTR()		(&mif6_mtx)
+#define	MIF6_LOCK()		mtx_lock(MIF6_LOCKPTR())
+#define	MIF6_UNLOCK()		mtx_unlock(MIF6_LOCKPTR())
+#define	MIF6_LOCK_ASSERT()	mtx_assert(MIF6_LOCKPTR(), MA_OWNED)
 #define	MIF6_LOCK_INIT()	\
-	mtx_init(&mif6_mtx, "IPv6 multicast interfaces", NULL, MTX_DEF)
-#define	MIF6_LOCK_DESTROY()	mtx_destroy(&mif6_mtx)
+	mtx_init(MIF6_LOCKPTR(), "IPv6 multicast interfaces", NULL, MTX_DEF)
+#define	MIF6_LOCK_DESTROY()	mtx_destroy(MIF6_LOCKPTR())
 
 #ifdef MRT6DEBUG
 VNET_DEFINE_STATIC(u_int, mrt6debug) = 0;	/* debug level */
@@ -583,11 +580,12 @@
 
 	V_pim6 = 0;/* used for stubbing out/in pim stuff */
 
-	callout_init(&expire_upcalls_ch, 0);
+	callout_init_mtx(&expire_upcalls_ch, MFC6_LOCKPTR(), 0);
 	callout_reset(&expire_upcalls_ch, EXPIRE_TIMEOUT,
 	    expire_upcalls, NULL);
 
 	MROUTER6_UNLOCK();
+
 	MRT6_DLOG(DEBUG_ANY, "finished");
 
 	return (0);
@@ -626,8 +624,6 @@
 
 	V_pim6 = 0; /* used to stub out/in pim specific code */
 
-	callout_stop(&expire_upcalls_ch);
-
 	/*
 	 * Free all multicast forwarding cache entries.
 	 */
@@ -652,6 +648,8 @@
 	bzero((caddr_t)mf6ctable, sizeof(mf6ctable));
 	MFC6_UNLOCK();
 
+	callout_drain(&expire_upcalls_ch);
+
 	/*
 	 * Reset register interface
 	 */
@@ -1315,7 +1313,8 @@
 	struct mf6c *mfc, **nptr;
 	u_long i;
 
-	MFC6_LOCK();
+	MFC6_LOCK_ASSERT();
+
 	for (i = 0; i < MF6CTBLSIZ; i++) {
 		if (n6expire[i] == 0)
 			continue;
@@ -1353,7 +1352,6 @@
 			}
 		}
 	}
-	MFC6_UNLOCK();
 	callout_reset(&expire_upcalls_ch, EXPIRE_TIMEOUT,
 	    expire_upcalls, NULL);
 }