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
@@ -2383,9 +2383,10 @@
 #endif
 
 	INP_WLOCK_ASSERT(inp);
-	MPASS(!callout_active(&tp->t_callout));
 	MPASS(TAILQ_EMPTY(&tp->snd_holes));
 
+	tcp_timer_stop(tp);
+
 	/* free the reassembly queue, if any */
 	tcp_reass_flush(tp);