Index: sys/kern/subr_sbuf.c
===================================================================
--- sys/kern/subr_sbuf.c
+++ sys/kern/subr_sbuf.c
@@ -388,8 +388,12 @@
 {
 	int len;
 
-	KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s));
-	KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s));
+	/*
+	 * Immediately return when no work to do,
+	 * or an error has already been accumulated.
+	 */
+	if ((s->s_len == 0) || (s->s_error != 0))
+		return(s->s_error);
 
 	if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0)
 		return (s->s_error = EDEADLK);
Index: sys/netinet/tcp_hostcache.c
===================================================================
--- sys/netinet/tcp_hostcache.c
+++ sys/netinet/tcp_hostcache.c
@@ -644,7 +644,6 @@
 	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
@@ -702,16 +701,12 @@
 			    hc_entry->rmx_hits,
 			    hc_entry->rmx_updates,
 			    hc_entry->rmx_expire);
-			do_drain = true;
 		}
 		THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 		/* Need to track if sbuf has data, to avoid
 		 * a KASSERT when calling sbuf_drain.
 		 */
-		if (do_drain) {
-			sbuf_drain(&sb);
-			do_drain = false;
-		}
+		sbuf_drain(&sb);
 	}
 #undef msec
 	error = sbuf_finish(&sb);