Index: head/sys/dev/uart/uart_bus.h
===================================================================
--- head/sys/dev/uart/uart_bus.h
+++ head/sys/dev/uart/uart_bus.h
@@ -111,6 +111,7 @@
 	int		sc_rxput;
 	int		sc_rxget;
 	int		sc_rxfifosz;	/* Size of RX FIFO. */
+	int		sc_rxoverruns;
 
 	/* Transmitter data. */
 	uint8_t		*sc_txbuf;
Index: head/sys/dev/uart/uart_core.c
===================================================================
--- head/sys/dev/uart/uart_core.c
+++ head/sys/dev/uart/uart_core.c
@@ -333,6 +333,7 @@
 			sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
 		uart_sched_softih(sc, SER_INT_RXREADY);
 	}
+	sc->sc_rxoverruns++;
 	UART_FLUSH(sc, UART_FLUSH_RECEIVER);
 	return (0);
 }
@@ -740,6 +741,12 @@
 
 	if (sc->sc_sysdev != NULL)
 		sc->sc_sysdev->hwmtx = sc->sc_hwmtx;
+
+	if (sc->sc_rxfifosz > 1)
+		SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
+		    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
+		    "rx_overruns", CTLFLAG_RD, &sc->sc_rxoverruns, 0,
+		    "Receive overruns");
 
 	return (0);