diff --git a/drivers/tty/serial/sunsab.c b/drivers/tty/serial/sunsab.c
index 8de2213664e0..a422c8b55a47 100644
--- a/drivers/tty/serial/sunsab.c
+++ b/drivers/tty/serial/sunsab.c
@@ -203,7 +203,7 @@ receive_chars(struct uart_sunsab_port *up,
 				flag = TTY_FRAME;
 		}
 
-		if (uart_handle_sysrq_char(&up->port, ch))
+		if (uart_handle_sysrq_char(&up->port, ch) || !port)
 			continue;
 
 		if ((stat->sreg.isr0 & (up->port.ignore_status_mask & 0xff)) == 0 &&
diff --git a/drivers/tty/serial/sunzilog.c b/drivers/tty/serial/sunzilog.c
index 27669ff3d446..813ef8eb8eff 100644
--- a/drivers/tty/serial/sunzilog.c
+++ b/drivers/tty/serial/sunzilog.c
@@ -388,7 +388,7 @@ sunzilog_receive_chars(struct uart_sunzilog_port *up,
 			else if (r1 & CRC_ERR)
 				flag = TTY_FRAME;
 		}
-		if (uart_handle_sysrq_char(&up->port, ch))
+		if (uart_handle_sysrq_char(&up->port, ch) || !port)
 			continue;
 
 		if (up->port.ignore_status_mask == 0xff ||