Index: sys/netinet/tcp_hostcache.c
===================================================================
--- sys/netinet/tcp_hostcache.c
+++ sys/netinet/tcp_hostcache.c
@@ -626,9 +626,8 @@
 static int
 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
 {
-	const int linesize = 128;
 	struct sbuf sb;
-	int i, error;
+	int i, error = 0;
 	struct hc_metrics *hc_entry;
 	char ip4buf[INET_ADDRSTRLEN];
 #ifdef INET6
@@ -638,48 +637,48 @@
 	if (jailed_without_vnet(curthread->td_ucred) != 0)
 		return (EPERM);
 
-	sbuf_new(&sb, NULL, linesize * (V_tcp_hostcache.cache_count + 1),
-		SBUF_INCLUDENUL);
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error == 0) {
+		sbuf_new_for_sysctl(&sb, NULL, 512, req);
 
-	sbuf_printf(&sb,
-	        "\nIP address        MTU  SSTRESH      RTT   RTTVAR "
-		"    CWND SENDPIPE RECVPIPE HITS  UPD  EXP\n");
+		sbuf_printf(&sb,
+			"\nIP address        MTU  SSTRESH      RTT   RTTVAR "
+			"    CWND SENDPIPE RECVPIPE HITS  UPD  EXP\n");
 
 #define msec(u) (((u) + 500) / 1000)
-	for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
-		THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
-		TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket,
-			      rmx_q) {
-			sbuf_printf(&sb,
-			    "%-15s %5u %8u %6lums %6lums %8u %8u %8u %4lu "
-			    "%4lu %4i\n",
-			    hc_entry->ip4.s_addr ?
-			        inet_ntoa_r(hc_entry->ip4, ip4buf) :
+		for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
+			THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
+			TAILQ_FOREACH(hc_entry,
+			    &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q) {
+				sbuf_printf(&sb,
+				    "%-15s %5u %8u %6lums %6lums %8u %8u "
+				    "%8u %4lu %4lu %4i\n",
+				    hc_entry->ip4.s_addr ?
+				        inet_ntoa_r(hc_entry->ip4, ip4buf) :
 #ifdef INET6
-				ip6_sprintf(ip6buf, &hc_entry->ip6),
+					ip6_sprintf(ip6buf, &hc_entry->ip6),
 #else
-				"IPv6?",
+					"IPv6?",
 #endif
-			    hc_entry->rmx_mtu,
-			    hc_entry->rmx_ssthresh,
-			    msec((u_long)hc_entry->rmx_rtt *
-				(RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
-			    msec((u_long)hc_entry->rmx_rttvar *
-				(RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
-			    hc_entry->rmx_cwnd,
-			    hc_entry->rmx_sendpipe,
-			    hc_entry->rmx_recvpipe,
-			    hc_entry->rmx_hits,
-			    hc_entry->rmx_updates,
-			    hc_entry->rmx_expire);
+				    hc_entry->rmx_mtu,
+				    hc_entry->rmx_ssthresh,
+				    msec((u_long)hc_entry->rmx_rtt *
+					(RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
+				    msec((u_long)hc_entry->rmx_rttvar *
+					(RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
+				    hc_entry->rmx_cwnd,
+				    hc_entry->rmx_sendpipe,
+				    hc_entry->rmx_recvpipe,
+				    hc_entry->rmx_hits,
+				    hc_entry->rmx_updates,
+				    hc_entry->rmx_expire);
+			}
+			THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 		}
-		THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
-	}
 #undef msec
-	error = sbuf_finish(&sb);
-	if (error == 0)
-		error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
-	sbuf_delete(&sb);
+		error = sbuf_finish(&sb);
+		sbuf_delete(&sb);
+	}
 	return(error);
 }