Re: [PATCH 1/3] tty: omap-serial: prevent division by zero
From: Frans Klaver <hidden>
Date: 2014-07-29 15:00:21
Also in:
linux-devicetree, lkml
Sorry, missed some CC's in git send-email. On Tue, Jul 29, 2014 at 04:52:55PM +0200, Frans Klaver wrote:
quoted hunk ↗ jump to hunk
If the chosen baud rate is large enough (e.g. 3.5 megabaud), the calculated n13 and n16 values in serial_omap_baud_is_mode16 may become 0. This causes a division by zero when calculating the difference between calculated and desired baud rates. To prevent this, cap n13 and n16 on 1. Signed-off-by: Frans Klaver <redacted> --- drivers/tty/serial/omap-serial.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index d017cec..e454b7c 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c@@ -254,8 +254,16 @@ serial_omap_baud_is_mode16(struct uart_port *port, unsigned int baud) { unsigned int n13 = port->uartclk / (13 * baud); unsigned int n16 = port->uartclk / (16 * baud); - int baudAbsDiff13 = baud - (port->uartclk / (13 * n13)); - int baudAbsDiff16 = baud - (port->uartclk / (16 * n16)); + int baudAbsDiff13; + int baudAbsDiff16; + + if (n13 == 0) + n13 = 1; + if (n16 == 0) + n16 = 1; + + baudAbsDiff13 = baud - (port->uartclk / (13 * n13)); + baudAbsDiff16 = baud - (port->uartclk / (16 * n16)); if (baudAbsDiff13 < 0) baudAbsDiff13 = -baudAbsDiff13; if (baudAbsDiff16 < 0)-- 1.9.3
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