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
@@ -2383,7 +2383,11 @@
 #endif
 
 	INP_WLOCK_ASSERT(inp);
-	MPASS(!callout_active(&tp->t_callout));
+	/* only allow TT_2MSL for TIMEWAIT */
+	MPASS(!tcp_timer_active(tp, TT_REXMT));
+	MPASS(!tcp_timer_active(tp, TT_PERSIST));
+	MPASS(!tcp_timer_active(tp, TT_KEEP));
+	MPASS(!tcp_timer_active(tp, TT_DELACK));
 	MPASS(TAILQ_EMPTY(&tp->snd_holes));
 
 	/* free the reassembly queue, if any */