diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -340,7 +340,8 @@
 		}
 	}
 
-	if (CC_ALGO(tp)->ack_received != NULL) {
+	KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+	if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->ack_received != NULL) {
 		/* XXXLAS: Find a way to live without this */
 		tp->t_ccv.curack = th->th_ack;
 		CC_ALGO(tp)->ack_received(&tp->t_ccv, type);
@@ -401,7 +402,8 @@
 	else
 		tp->snd_cwnd = tcp_compute_initwnd(maxseg);
 
-	if (CC_ALGO(tp)->conn_init != NULL)
+	KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+	if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->conn_init != NULL)
 		CC_ALGO(tp)->conn_init(&tp->t_ccv);
 }
 
@@ -462,7 +464,8 @@
 		break;
 	}
 
-	if (CC_ALGO(tp)->cong_signal != NULL) {
+	KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+	if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->cong_signal != NULL) {
 		if (th != NULL)
 			tp->t_ccv.curack = th->th_ack;
 		CC_ALGO(tp)->cong_signal(&tp->t_ccv, type);
@@ -474,7 +477,8 @@
 {
 	INP_WLOCK_ASSERT(tptoinpcb(tp));
 
-	if (CC_ALGO(tp)->post_recovery != NULL) {
+	KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+	if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->post_recovery != NULL) {
 		tp->t_ccv.curack = th->th_ack;
 		CC_ALGO(tp)->post_recovery(&tp->t_ccv);
 	}
@@ -506,7 +510,8 @@
 {
 	INP_WLOCK_ASSERT(tptoinpcb(tp));
 
-	if (CC_ALGO(tp)->ecnpkt_handler != NULL) {
+	KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+	if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->ecnpkt_handler != NULL) {
 		switch (iptos & IPTOS_ECN_MASK) {
 		case IPTOS_ECN_CE:
 			tp->t_ccv.flags |= CCF_IPHDR_CE;
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -178,7 +178,8 @@
 {
 	INP_WLOCK_ASSERT(tptoinpcb(tp));
 
-	if (CC_ALGO(tp)->after_idle != NULL)
+	KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+	if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->after_idle != NULL)
 		CC_ALGO(tp)->after_idle(&tp->t_ccv);
 }
 
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -2401,7 +2401,7 @@
 #endif
 
 	/* Allow the CC algorithm to clean up after itself. */
-	if (CC_ALGO(tp)->cb_destroy != NULL)
+	if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->cb_destroy != NULL)
 		CC_ALGO(tp)->cb_destroy(&tp->t_ccv);
 	CC_DATA(tp) = NULL;
 	/* Detach from the CC algorithm */
diff --git a/sys/netinet/tcp_timer.c b/sys/netinet/tcp_timer.c
--- a/sys/netinet/tcp_timer.c
+++ b/sys/netinet/tcp_timer.c
@@ -742,7 +742,8 @@
 			 * Reset the slow-start flight size
 			 * as it may depend on the new MSS.
 			 */
-			if (CC_ALGO(tp)->conn_init != NULL)
+			KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+			if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->conn_init != NULL)
 				CC_ALGO(tp)->conn_init(&tp->t_ccv);
 		} else {
 			/*
@@ -761,7 +762,8 @@
 				 * Reset the slow-start flight size as it
 				 * may depend on the new MSS.
 				 */
-				if (CC_ALGO(tp)->conn_init != NULL)
+				KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+				if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->conn_init != NULL)
 					CC_ALGO(tp)->conn_init(&tp->t_ccv);
 			}
 		}
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -2031,7 +2031,8 @@
 		 * copying in the cc_mem after we call
 		 * the old ones cleanup (if any).
 		 */
-		if (CC_ALGO(tp)->cb_destroy != NULL)
+		KASSERT(CC_ALGO(tp) != NULL, ("CC algo is NULL\n"));
+		if (CC_ALGO(tp) != NULL && CC_ALGO(tp)->cb_destroy != NULL)
 			CC_ALGO(tp)->cb_destroy(&tp->t_ccv);
 		/* Detach the old CC from the tcpcb  */
 		cc_detach(tp);