From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753557AbaIXHzh (ORCPT ); Wed, 24 Sep 2014 03:55:37 -0400 Received: from filter1.ibarracuda.nl ([83.247.7.10]:42812 "EHLO filter1.ibarracuda.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753085AbaIXHzd (ORCPT ); Wed, 24 Sep 2014 03:55:33 -0400 X-ASG-Debug-ID: 1411545330-0759e7612989fa40002-xx1T2L X-Barracuda-Envelope-From: Frans.Klaver@xsens.com X-Barracuda-AUTH-User: xsenscom X-Barracuda-Apparent-Source-IP: 87.249.116.215 From: Frans Klaver To: Greg Kroah-Hartman CC: Frans Klaver , Jiri Slaby , , , Subject: [PATCH 1/2] tty: omap-serial: fix division by zero Date: Wed, 24 Sep 2014 09:55:21 +0200 X-ASG-Orig-Subj: [PATCH 1/2] tty: omap-serial: fix division by zero Message-ID: <1411545322-22940-2-git-send-email-frans.klaver@xsens.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1411545322-22940-1-git-send-email-frans.klaver@xsens.com> References: <1411545322-22940-1-git-send-email-frans.klaver@xsens.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [172.16.11.160] X-Barracuda-Connect: rev-215.116.249.87.virtu.nl[87.249.116.215] X-Barracuda-Start-Time: 1411545331 X-Barracuda-Encrypted: AES128-SHA X-Barracuda-URL: http://filter1.ibarracuda.nl:8000/cgi-mod/mark.cgi X-Barracuda-BRTS-Status: 1 X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=5.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.9817 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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) -- 2.1.0