USB: serial: io_ti: fix div-by-zero in set_termios

Fix a division-by-zero in set_termios when debugging is enabled and a
high-enough speed has been requested so that the divisor value becomes
zero.

Instead of just fixing the offending debug statement, cap the baud rate
at the base as a zero divisor value also appears to crash the firmware.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>     # 2.6.12
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index 87798e625d6c827ed09b79a011eb46cdd770c864..6cefb9cb133d7bad8678e9b9400b077afc75474e 100644 (file)
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -2336,8 +2336,11 @@ static void change_port_settings(struct tty_struct *tty,
        if (!baud) {
                /* pick a default, any default... */
                baud = 9600;
-       } else
+       } else {
+               /* Avoid a zero divisor. */
+               baud = min(baud, 461550);
                tty_encode_baud_rate(tty, baud, baud);
+       }
 
        edge_port->baud_rate = baud;
        config->wBaudRate = (__u16)((461550L + baud/2) / baud);