Index: sys/netinet/tcp_hostcache.c
===================================================================
--- sys/netinet/tcp_hostcache.c
+++ sys/netinet/tcp_hostcache.c
@@ -633,6 +633,7 @@
 	const int linesize = 128;
 	struct sbuf sb;
 	int i, error, len;
+	bool do_drain = false;
 	struct hc_metrics *hc_entry;
 	char ip4buf[INET_ADDRSTRLEN];
 #ifdef INET6
@@ -688,9 +689,13 @@
 			    hc_entry->rmx_hits,
 			    hc_entry->rmx_updates,
 			    hc_entry->rmx_expire);
+			do_drain = true;
 		}
 		THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
-		sbuf_drain(&sb);
+		if (do_drain) {
+			sbuf_drain(&sb);
+			do_drain = false;
+		}
 	}
 #undef msec
 	error = sbuf_finish(&sb);