Index: head/sys/netinet/cc/cc_chd.c
===================================================================
--- head/sys/netinet/cc/cc_chd.c
+++ head/sys/netinet/cc/cc_chd.c
@@ -307,8 +307,7 @@
 chd_cb_destroy(struct cc_var *ccv)
 {
 
-	if (ccv->cc_data != NULL)
-		free(ccv->cc_data, M_CHD);
+	free(ccv->cc_data, M_CHD);
 }
 
 static int
Index: head/sys/netinet/cc/cc_cubic.c
===================================================================
--- head/sys/netinet/cc/cc_cubic.c
+++ head/sys/netinet/cc/cc_cubic.c
@@ -213,9 +213,7 @@
 static void
 cubic_cb_destroy(struct cc_var *ccv)
 {
-
-	if (ccv->cc_data != NULL)
-		free(ccv->cc_data, M_CUBIC);
+	free(ccv->cc_data, M_CUBIC);
 }
 
 static int
Index: head/sys/netinet/cc/cc_dctcp.c
===================================================================
--- head/sys/netinet/cc/cc_dctcp.c
+++ head/sys/netinet/cc/cc_dctcp.c
@@ -184,8 +184,7 @@
 static void
 dctcp_cb_destroy(struct cc_var *ccv)
 {
-	if (ccv->cc_data != NULL)
-		free(ccv->cc_data, M_dctcp);
+	free(ccv->cc_data, M_dctcp);
 }
 
 static int
Index: head/sys/netinet/cc/cc_htcp.c
===================================================================
--- head/sys/netinet/cc/cc_htcp.c
+++ head/sys/netinet/cc/cc_htcp.c
@@ -238,9 +238,7 @@
 static void
 htcp_cb_destroy(struct cc_var *ccv)
 {
-
-	if (ccv->cc_data != NULL)
-		free(ccv->cc_data, M_HTCP);
+	free(ccv->cc_data, M_HTCP);
 }
 
 static int
Index: head/sys/netinet/cc/cc_newreno.c
===================================================================
--- head/sys/netinet/cc/cc_newreno.c
+++ head/sys/netinet/cc/cc_newreno.c
@@ -127,9 +127,7 @@
 static void
 newreno_cb_destroy(struct cc_var *ccv)
 {
-
-	if (ccv->cc_data != NULL)
-		free(ccv->cc_data, M_NEWRENO);
+	free(ccv->cc_data, M_NEWRENO);
 }
 
 static void
Index: head/sys/netinet/cc/cc_vegas.c
===================================================================
--- head/sys/netinet/cc/cc_vegas.c
+++ head/sys/netinet/cc/cc_vegas.c
@@ -170,9 +170,7 @@
 static void
 vegas_cb_destroy(struct cc_var *ccv)
 {
-
-	if (ccv->cc_data != NULL)
-		free(ccv->cc_data, M_VEGAS);
+	free(ccv->cc_data, M_VEGAS);
 }
 
 static int
Index: head/sys/netinet/tcp_subr.c
===================================================================
--- head/sys/netinet/tcp_subr.c
+++ head/sys/netinet/tcp_subr.c
@@ -1730,10 +1730,18 @@
 				 */
 				if (CC_ALGO(tp) == unload_algo) {
 					tmpalgo = CC_ALGO(tp);
-					/* NewReno does not require any init. */
-					CC_ALGO(tp) = &newreno_cc_algo;
 					if (tmpalgo->cb_destroy != NULL)
 						tmpalgo->cb_destroy(tp->ccv);
+					CC_DATA(tp) = NULL;
+					/*
+					 * NewReno may allocate memory on
+					 * demand for certain stateful
+					 * configuration as needed, but is
+					 * coded to never fail on memory
+					 * allocation failure so it is a safe
+					 * fallback.
+					 */
+					CC_ALGO(tp) = &newreno_cc_algo;
 				}
 			}
 			INP_WUNLOCK(inp);
@@ -1885,6 +1893,7 @@
 	/* Allow the CC algorithm to clean up after itself. */
 	if (CC_ALGO(tp)->cb_destroy != NULL)
 		CC_ALGO(tp)->cb_destroy(tp->ccv);
+	CC_DATA(tp) = NULL;
 
 #ifdef TCP_HHOOK
 	khelp_destroy_osd(tp->osd);
Index: head/sys/netinet/tcp_usrreq.c
===================================================================
--- head/sys/netinet/tcp_usrreq.c
+++ head/sys/netinet/tcp_usrreq.c
@@ -1729,6 +1729,7 @@
 			 */
 			if (CC_ALGO(tp)->cb_destroy != NULL)
 				CC_ALGO(tp)->cb_destroy(tp->ccv);
+			CC_DATA(tp) = NULL;
 			CC_ALGO(tp) = algo;
 			/*
 			 * If something goes pear shaped initialising the new