From patchwork Thu Sep 25 09:19:51 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frans Klaver X-Patchwork-Id: 4973921 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 3CB26BEEA6 for ; Thu, 25 Sep 2014 09:20:40 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9DA54202AE for ; Thu, 25 Sep 2014 09:20:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A58120253 for ; Thu, 25 Sep 2014 09:20:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753043AbaIYJUL (ORCPT ); Thu, 25 Sep 2014 05:20:11 -0400 Received: from filter1.ibarracuda.nl ([83.247.7.10]:59007 "EHLO filter1.ibarracuda.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753000AbaIYJUG (ORCPT ); Thu, 25 Sep 2014 05:20:06 -0400 X-ASG-Debug-ID: 1411636795-0759e70b7317db60002-g9IbbW Received: from XSMCASSVR01.xsens-tech.local (rev-215.116.249.87.virtu.nl [87.249.116.215]) by filter1.ibarracuda.nl with ESMTP id DZddSFZN0weRzIKQ (version=TLSv1 cipher=AES128-SHA bits=128 verify=NO); Thu, 25 Sep 2014 11:19:55 +0200 (CEST) X-Barracuda-Envelope-From: Frans.Klaver@xsens.com X-Barracuda-AUTH-User: xsenscom X-Barracuda-Apparent-Source-IP: 87.249.116.215 Received: from ci00147.xsens-tech.local (172.16.11.160) by XSMCASSVR01.xsens-tech.local (192.168.0.248) with Microsoft SMTP Server id 14.3.195.1; Thu, 25 Sep 2014 11:19:56 +0200 From: Frans Klaver To: Greg Kroah-Hartman CC: , Frans Klaver , Jiri Slaby , , , Subject: [PATCH resend 1/2] tty: omap-serial: fix division by zero Date: Thu, 25 Sep 2014 11:19:51 +0200 X-ASG-Orig-Subj: [PATCH resend 1/2] tty: omap-serial: fix division by zero Message-ID: <1411636791-24116-1-git-send-email-frans.klaver@xsens.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <20140924080852.GA28215@kroah.com> References: <20140924080852.GA28215@kroah.com> MIME-Version: 1.0 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: 1411636795 X-Barracuda-Encrypted: AES128-SHA X-Barracuda-URL: http://filter1.ibarracuda.nl:8000/cgi-mod/mark.cgi X-Virus-Scanned: by bsmtpd at ibarracuda.nl 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 3.2.3.9857 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- Resend to add stable@vger.kernel.org to CC. As far as I know, this applies to v3.9 and up. Thanks, Frans 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)