From 1e6e9c4c36f9626d5ad2b63aa7ad5686dde737e7 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 11 May 2017 11:41:21 +0200
Subject: [PATCH] USB: serial: io_ti: fix div-by-zero in set_termios
commit 6aeb75e6adfaed16e58780309613a578fe1ee90b upstream.
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")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/serial/io_ti.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index f1a8fdcd8674..e98532feb0cc 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -2349,8 +2349,11 @@ 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);