[PATCH 4.4 039/118] serial: 8250_mid: fix divide error bug if baud rate is 0
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2016-09-22 17:34:46
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
commit 47b34d2ef266e2c283b514d65c8963c2ccd42474 upstream.
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" <redacted>
Fixes: c1a67b48f6a5 ("serial: 8250_pci: replace switch-case by formula for Intel MID")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/8250/8250_mid.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/tty/serial/8250/8250_mid.c
+++ b/drivers/tty/serial/8250/8250_mid.c@@ -149,6 +149,9 @@ static void mid8250_set_termios(struct u 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)