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
@@ -2268,11 +2268,11 @@
 		V_tcp_mssdflt;
 
 	/* Set up our timeouts. */
-	callout_init(&tp->t_timers->tt_rexmt, 1);
-	callout_init(&tp->t_timers->tt_persist, 1);
-	callout_init(&tp->t_timers->tt_keep, 1);
-	callout_init(&tp->t_timers->tt_2msl, 1);
-	callout_init(&tp->t_timers->tt_delack, 1);
+	callout_init_rw(&tp->t_timers->tt_rexmt, &inp->inp_lock, CALLOUT_RETURNUNLOCKED);
+	callout_init_rw(&tp->t_timers->tt_persist, &inp->inp_lock, CALLOUT_RETURNUNLOCKED);
+	callout_init_rw(&tp->t_timers->tt_keep, &inp->inp_lock, CALLOUT_RETURNUNLOCKED);
+	callout_init_rw(&tp->t_timers->tt_2msl, &inp->inp_lock, CALLOUT_RETURNUNLOCKED);
+	callout_init_rw(&tp->t_timers->tt_delack, &inp->inp_lock, CALLOUT_RETURNUNLOCKED);
 
 	if (V_tcp_do_rfc1323)
 		tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
@@ -2353,6 +2353,16 @@
 	return (tcp_close(tp));
 }
 
+void
+tcp_timer_stop_all(struct tcpcb *tp)
+{
+	tcp_timer_stop(tp, TT_REXMT);
+	tcp_timer_stop(tp, TT_PERSIST);
+	tcp_timer_stop(tp, TT_KEEP);
+	tcp_timer_stop(tp, TT_2MSL);
+	tcp_timer_stop(tp, TT_DELACK);
+}
+
 void
 tcp_discardcb(struct tcpcb *tp)
 {
@@ -2369,11 +2379,7 @@
 	 * deleting the tcpcb.
 	 */
 	tp->t_timers->tt_draincnt = 0;
-	tcp_timer_stop(tp, TT_REXMT);
-	tcp_timer_stop(tp, TT_PERSIST);
-	tcp_timer_stop(tp, TT_KEEP);
-	tcp_timer_stop(tp, TT_2MSL);
-	tcp_timer_stop(tp, TT_DELACK);
+	tcp_timer_stop_all(tp);
 	if (tp->t_fb->tfb_tcp_timer_stop_all) {
 		/*
 		 * Call the stop-all function of the methods,
@@ -2544,6 +2550,7 @@
 #ifdef TCPHPTS
 	tcp_hpts_remove(inp);
 #endif
+	tcp_timer_stop_all(tp);
 	in_pcbdrop(inp);
 	TCPSTAT_INC(tcps_closed);
 	if (tp->t_state != TCPS_CLOSED)
@@ -4053,18 +4060,18 @@
 			     (tp->t_flags2 & TF2_ACE_PERMIT) ? 2 : 0;
 
 		now = getsbinuptime();
-#define	COPYTIMER(ttt)	do {						\
-		if (callout_active(&tp->t_timers->ttt))			\
+#define	COPYTIMER(ttt,TTT) do {						\
+		  if (tp->t_timers->tt_flags & TTT)			\
 			xt->ttt = (tp->t_timers->ttt.c_time - now) /	\
 			    SBT_1MS;					\
 		else							\
 			xt->ttt = 0;					\
 } while (0)
-		COPYTIMER(tt_delack);
-		COPYTIMER(tt_rexmt);
-		COPYTIMER(tt_persist);
-		COPYTIMER(tt_keep);
-		COPYTIMER(tt_2msl);
+		COPYTIMER(tt_delack, TT_DELACK);
+		COPYTIMER(tt_rexmt, TT_REXMT);
+		COPYTIMER(tt_persist, TT_PERSIST);
+		COPYTIMER(tt_keep, TT_KEEP);
+		COPYTIMER(tt_2msl, TT_2MSL);
 #undef COPYTIMER
 		xt->t_rcvtime = 1000 * (ticks - tp->t_rcvtime) / hz;
 
diff --git a/sys/netinet/tcp_timer.c b/sys/netinet/tcp_timer.c
--- a/sys/netinet/tcp_timer.c
+++ b/sys/netinet/tcp_timer.c
@@ -282,21 +282,9 @@
 	struct inpcb *inp;
 	CURVNET_SET(tp->t_vnet);
 
+	tp->t_timers->tt_flags &= ~TT_DELACK;
 	inp = tp->t_inpcb;
 	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
-	INP_WLOCK(inp);
-	if (callout_pending(&tp->t_timers->tt_delack) ||
-	    !callout_active(&tp->t_timers->tt_delack)) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
-	callout_deactivate(&tp->t_timers->tt_delack);
-	if ((inp->inp_flags & INP_DROPPED) != 0) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
 	tp->t_flags |= TF_ACKNOW;
 	TCPSTAT_INC(tcps_delack);
 	NET_EPOCH_ENTER(et);
@@ -324,22 +312,11 @@
 
 	ostate = tp->t_state;
 #endif
+	tp->t_timers->tt_flags &= ~TT_2MSL;
 	inp = tp->t_inpcb;
 	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
-	INP_WLOCK(inp);
+
 	tcp_free_sackholes(tp);
-	if (callout_pending(&tp->t_timers->tt_2msl) ||
-	    !callout_active(&tp->t_timers->tt_2msl)) {
-		INP_WUNLOCK(tp->t_inpcb);
-		CURVNET_RESTORE();
-		return;
-	}
-	callout_deactivate(&tp->t_timers->tt_2msl);
-	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
 	KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
 		("%s: tp %p tcpcb can't be stopped here", __func__, tp));
 	/*
@@ -363,6 +340,7 @@
 		goto out;
 	} else {
 		if (ticks - tp->t_rcvtime <= TP_MAXIDLE(tp)) {
+			tp->t_timers->tt_flags |= TT_2MSL;
 			callout_reset(&tp->t_timers->tt_2msl,
 				      TP_KEEPINTVL(tp), tcp_timer_2msl, tp);
 		} else {
@@ -400,21 +378,10 @@
 
 	ostate = tp->t_state;
 #endif
+	tp->t_timers->tt_flags &= ~TT_KEEP;
 	inp = tp->t_inpcb;
 	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
-	INP_WLOCK(inp);
-	if (callout_pending(&tp->t_timers->tt_keep) ||
-	    !callout_active(&tp->t_timers->tt_keep)) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
-	callout_deactivate(&tp->t_timers->tt_keep);
-	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
+
 	KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
 		("%s: tp %p tcpcb can't be stopped here", __func__, tp));
 
@@ -429,6 +396,7 @@
 
 		idletime = ticks - tp->t_rcvtime;
 		if (idletime < TP_KEEPIDLE(tp)) {
+			tp->t_timers->tt_flags |= TT_KEEP;
 			callout_reset(&tp->t_timers->tt_keep,
 			    TP_KEEPIDLE(tp) - idletime, tcp_timer_keep, tp);
 			INP_WUNLOCK(inp);
@@ -471,11 +439,14 @@
 			NET_EPOCH_EXIT(et);
 			free(t_template, M_TEMP);
 		}
+		tp->t_timers->tt_flags |= TT_KEEP;
 		callout_reset(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp),
 			      tcp_timer_keep, tp);
-	} else
+	} else {
+		tp->t_timers->tt_flags |= TT_KEEP;
 		callout_reset(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp),
 			      tcp_timer_keep, tp);
+	}
 
 #ifdef TCPDEBUG
 	if (inp->inp_socket->so_options & SO_DEBUG)
@@ -516,21 +487,9 @@
 
 	ostate = tp->t_state;
 #endif
+	tp->t_timers->tt_flags &= ~TT_PERSIST;
 	inp = tp->t_inpcb;
 	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
-	INP_WLOCK(inp);
-	if (callout_pending(&tp->t_timers->tt_persist) ||
-	    !callout_active(&tp->t_timers->tt_persist)) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
-	callout_deactivate(&tp->t_timers->tt_persist);
-	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
 	KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
 		("%s: tp %p tcpcb can't be stopped here", __func__, tp));
 	/*
@@ -599,21 +558,9 @@
 
 	ostate = tp->t_state;
 #endif
+	tp->t_timers->tt_flags &= ~TT_REXMT;
 	inp = tp->t_inpcb;
 	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
-	INP_WLOCK(inp);
-	if (callout_pending(&tp->t_timers->tt_rexmt) ||
-	    !callout_active(&tp->t_timers->tt_rexmt)) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
-	callout_deactivate(&tp->t_timers->tt_rexmt);
-	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
-		INP_WUNLOCK(inp);
-		CURVNET_RESTORE();
-		return;
-	}
 	KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
 		("%s: tp %p tcpcb can't be stopped here", __func__, tp));
 	tcp_free_sackholes(tp);
@@ -902,15 +849,15 @@
 			f_callout = tcp_timer_2msl;
 			break;
 		default:
-			if (tp->t_fb->tfb_tcp_timer_activate) {
-				tp->t_fb->tfb_tcp_timer_activate(tp, timer_type, delta);
-				return;
-			}
-			panic("tp %p bad timer_type %#x", tp, timer_type);
-		}
+			MPASS(tp->t_fb->tfb_tcp_timer_activate != NULL);
+			tp->t_fb->tfb_tcp_timer_activate(tp, timer_type, delta);
+			return;
+	}
 	if (delta == 0) {
+		tp->t_timers->tt_flags &= ~timer_type;
 		callout_stop(t_callout);
 	} else {
+		tp->t_timers->tt_flags |= timer_type;
 		callout_reset_on(t_callout, delta, f_callout, tp, cpu);
 	}
 }
@@ -918,31 +865,17 @@
 int
 tcp_timer_active(struct tcpcb *tp, uint32_t timer_type)
 {
-	struct callout *t_callout;
-
 	switch (timer_type) {
-		case TT_DELACK:
-			t_callout = &tp->t_timers->tt_delack;
-			break;
-		case TT_REXMT:
-			t_callout = &tp->t_timers->tt_rexmt;
-			break;
-		case TT_PERSIST:
-			t_callout = &tp->t_timers->tt_persist;
-			break;
-		case TT_KEEP:
-			t_callout = &tp->t_timers->tt_keep;
-			break;
-		case TT_2MSL:
-			t_callout = &tp->t_timers->tt_2msl;
-			break;
-		default:
-			if (tp->t_fb->tfb_tcp_timer_active) {
-				return(tp->t_fb->tfb_tcp_timer_active(tp, timer_type));
-			}
-			panic("tp %p bad timer_type %#x", tp, timer_type);
-		}
-	return callout_active(t_callout);
+	case TT_DELACK:
+	case TT_REXMT:
+	case TT_PERSIST:
+	case TT_KEEP:
+	case TT_2MSL:
+		return ((tp->t_timers->tt_flags & timer_type) ? 1 : 0);
+	default:
+		MPASS(tp->t_fb->tfb_tcp_timer_active != NULL);
+		return (tp->t_fb->tfb_tcp_timer_active(tp, timer_type));
+	}
 }
 
 /*
@@ -1006,7 +939,7 @@
 			if (tp->t_timers->tt_flags & TT_REXMT_SUS) {
 				tp->t_timers->tt_flags &= ~TT_REXMT_SUS;
 				if (SEQ_GT(tp->snd_max, tp->snd_una) &&
-				    (tcp_timer_active((tp), TT_PERSIST) == 0) &&
+				    (tcp_timer_active(tp, TT_PERSIST) == 0) &&
 				    tp->snd_wnd) {
 					/* We have outstanding data activate a timer */
 					tcp_timer_activate(tp, TT_REXMT,
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -1195,6 +1195,7 @@
 void	 tcp_timers_unsuspend(struct tcpcb *, uint32_t);
 int	 tcp_timer_active(struct tcpcb *, uint32_t);
 void	 tcp_timer_stop(struct tcpcb *, uint32_t);
+void	 tcp_timer_stop_all(struct tcpcb *);
 void	 tcp_trace(short, short, struct tcpcb *, void *, struct tcphdr *, int);
 int	 inp_to_cpuid(struct inpcb *inp);
 /*