From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754042AbaJ0TYG (ORCPT ); Mon, 27 Oct 2014 15:24:06 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:52520 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752885AbaJ0TAp (ORCPT ); Mon, 27 Oct 2014 15:00:45 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Frans Klaver , Greg Kroah-Hartman , Kamal Mostafa Subject: [PATCH 3.13 063/105] tty: omap-serial: fix division by zero Date: Mon, 27 Oct 2014 11:56:38 -0700 Message-Id: <1414436240-13879-64-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1414436240-13879-1-git-send-email-kamal@canonical.com> References: <1414436240-13879-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Frans Klaver commit dc3187564e61260f49eceb21a4e7eb5e4428e90a upstream. 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. [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (Ldiv0+0x8/0x10) [] (Ldiv0) from [] (serial_omap_baud_is_mode16+0x4c/0x68) [] (serial_omap_baud_is_mode16) from [] (serial_omap_set_termios+0x90/0x8d8) [] (serial_omap_set_termios) from [] (uart_change_speed+0xa4/0xa8) [] (uart_change_speed) from [] (uart_set_termios+0xa0/0x1fc) [] (uart_set_termios) from [] (tty_set_termios+0x248/0x2c0) [] (tty_set_termios) from [] (set_termios+0x248/0x29c) [] (set_termios) from [] (tty_mode_ioctl+0x1c8/0x4e8) [] (tty_mode_ioctl) from [] (tty_ioctl+0xa94/0xb18) [] (tty_ioctl) from [] (do_vfs_ioctl+0x4a0/0x560) [] (do_vfs_ioctl) from [] (SyS_ioctl+0x4c/0x74) [] (SyS_ioctl) from [] (ret_fast_syscall+0x0/0x30) Signed-off-by: Frans Klaver Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa --- 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 f5d0720..270d084 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -260,8 +260,16 @@ 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) -- 1.9.1