This is a note to let you know that I've just added the patch titled
tty: omap-serial: fix division by zero
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From dc3187564e61260f49eceb21a4e7eb5e4428e90a Mon Sep 17 00:00:00 2001
From: Frans Klaver <frans.klaver@xxxxxxxxx>
Date: Thu, 25 Sep 2014 11:19:51 +0200
Subject: tty: omap-serial: fix division by zero
If the chosen baud rate is large enough (e.g. 3.5 megabaud), the
calculated n values in serial_omap_is_baud_mode16() may become 0. This
causes a division by zero when calculating the difference between
calculated and desired baud rates. To prevent this, cap the n13 and n16
values on 1.
Division by zero in kernel.
[<c00132e0>] (unwind_backtrace) from [<c00112ec>] (show_stack+0x10/0x14)
[<c00112ec>] (show_stack) from [<c01ed7bc>] (Ldiv0+0x8/0x10)
[<c01ed7bc>] (Ldiv0) from [<c023805c>] (serial_omap_baud_is_mode16+0x4c/0x68)
[<c023805c>] (serial_omap_baud_is_mode16) from [<c02396b4>] (serial_omap_set_termios+0x90/0x8d8)
[<c02396b4>] (serial_omap_set_termios) from [<c0230a0c>] (uart_change_speed+0xa4/0xa8)
[<c0230a0c>] (uart_change_speed) from [<c0231798>] (uart_set_termios+0xa0/0x1fc)
[<c0231798>] (uart_set_termios) from [<c022bb44>] (tty_set_termios+0x248/0x2c0)
[<c022bb44>] (tty_set_termios) from [<c022c17c>] (set_termios+0x248/0x29c)
[<c022c17c>] (set_termios) from [<c022c3e4>] (tty_mode_ioctl+0x1c8/0x4e8)
[<c022c3e4>] (tty_mode_ioctl) from [<c0227e70>] (tty_ioctl+0xa94/0xb18)
[<c0227e70>] (tty_ioctl) from [<c00cf45c>] (do_vfs_ioctl+0x4a0/0x560)
[<c00cf45c>] (do_vfs_ioctl) from [<c00cf568>] (SyS_ioctl+0x4c/0x74)
[<c00cf568>] (SyS_ioctl) from [<c000e480>] (ret_fast_syscall+0x0/0x30)
Signed-off-by: Frans Klaver <frans.klaver@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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 d017cec8a34a..e454b7c2ecd9 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)
--
2.1.1
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