1 files changed, 12 insertions, 1 deletions

diff --git a/sys/dev/sio/sio.c b/sys/dev/sio/sio.c
index 6415fb5ac5724..9bf4dfa748431 100644
--- a/sys/dev/sio/sio.c
+++ b/sys/dev/sio/sio.c
@@ -1792,9 +1792,20 @@ siointr1(com)
 			}
 		}
 		line_status = inb(com->line_status_port);
-
+		if (line_status == 0xff) {
+			printf("sio%d: spouting nonsense -- disabled.\n",
+			    com->unit);
+			com->gone = 1;
+			break;
+		}
 		/* input event? (check first to help avoid overruns) */
 		while (line_status & LSR_RCV_MASK) {
+			if (line_status == 0xff) {
+				printf("sio%d: linestats bogus -- disabled.\n",
+				    com->unit);
+				com->gone = 1;
+				return;
+			}
 			/* break/unnattached error bits or real input? */
 			if (!(line_status & LSR_RXRDY))
 				recv_data = 0;