From 47b34d2ef266e2c283b514d65c8963c2ccd42474 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Fri, 1 Jul 2016 17:21:49 +0300 Subject: [PATCH] serial: 8250_mid: fix divide error bug if baud rate is 0 Since the commit c1a67b48f6a5 ("serial: 8250_pci: replace switch-case by formula for Intel MID"), the 8250 driver crashes in the byt_set_termios() function with a divide error. This is caused by the fact that a baud rate of 0 (B0) is not handled properly. Fix it by falling back to B9600 in this case. Reported-by: "Mendez Salinas, Fernando" Fixes: c1a67b48f6a5 ("serial: 8250_pci: replace switch-case by formula for Intel MID") Cc: stable@vger.kernel.org Signed-off-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_mid.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c index 339de9cd0866..20c5db2f4264 100644 --- a/drivers/tty/serial/8250/8250_mid.c +++ b/drivers/tty/serial/8250/8250_mid.c @@ -168,6 +168,9 @@ static void mid8250_set_termios(struct uart_port *p, unsigned long w = BIT(24) - 1; unsigned long mul, div; + /* Gracefully handle the B0 case: fall back to B9600 */ + fuart = fuart ? fuart : 9600 * 16; + if (mid->board->freq < fuart) { /* Find prescaler value that satisfies Fuart < Fref */ if (mid->board->freq > baud) -- 2.20.1