[PATCH 5/8] serial: Fix crash if the minimum rate of the device is > 9600 baud

[Greg Kroah-Hartman]

From: Alan Cox <alan@xxxxxxxxxxxxxxx>

In that situation if the old rate is invalid and the new rate is invalid
and the chip cannot do 9600 baud we report zero, which makes all the
drivers explode.

Instead force the rate based on min/max

Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 drivers/serial/serial_core.c |   17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index fa4f170..7f28307 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -385,13 +385,20 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 		}
 
 		/*
-		 * As a last resort, if the quotient is zero,
-		 * default to 9600 bps
+		 * As a last resort, if the range cannot be met then clip to
+		 * the nearest chip supported rate.
 		 */
-		if (!hung_up)
-			tty_termios_encode_baud_rate(termios, 9600, 9600);
+		if (!hung_up) {
+			if (baud <= min)
+				tty_termios_encode_baud_rate(termios,
+							min + 1, min + 1);
+			else
+				tty_termios_encode_baud_rate(termios,
+							max - 1, max - 1);
+		}
 	}
-
+	/* Should never happen */
+	WARN_ON(1);
 	return 0;
 }
 
-- 
1.6.5.7

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/