From dc3187564e61260f49eceb21a4e7eb5e4428e90a Mon Sep 17 00:00:00 2001 From: Frans Klaver <frans.klaver@xsens.com> 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@xsens.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/tty/serial/omap-serial.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index d017cec8a34..e454b7c2ecd 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) -- cgit v1.2.3-70-g09d2