From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1B50C433B4 for ; Mon, 26 Apr 2021 08:08:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7040461075 for ; Mon, 26 Apr 2021 08:08:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232266AbhDZIJQ (ORCPT ); Mon, 26 Apr 2021 04:09:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:54904 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232114AbhDZIJP (ORCPT ); Mon, 26 Apr 2021 04:09:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B22C661075; Mon, 26 Apr 2021 08:08:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1619424513; bh=/sO2t0hU88ihYrgppTs+DSbTAXvGpptkwOt7IzR76uE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jk8u5CJ9jK8F1AgHr9yS7fAuZvZIBF1VnI0xl9JMRZ7AG9RzX0T5jr4M8WfPgi+uP 03QS86rcI9mLsu8Do/LTvzrl1fK3h5KG3d4XVAvYZQzEycoNl6ghTdjgtEDZxhNiZa OxrVoPfuYaZEn58pXsC23q9l1GUSwtV6oQ+g8AkU= Date: Mon, 26 Apr 2021 10:08:30 +0200 From: Greg KH To: Sherry Sun Cc: jirislaby@kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-imx@nxp.com Subject: Re: [PATCH 1/2] tty: serial: fsl_lpuart: fix the potential bug of division or modulo by zero Message-ID: References: <20210426074935.11131-1-sherry.sun@nxp.com> <20210426074935.11131-2-sherry.sun@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210426074935.11131-2-sherry.sun@nxp.com> Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Mon, Apr 26, 2021 at 03:49:34PM +0800, Sherry Sun wrote: > This issue is reported by Coverity Check. > In lpuart32_console_get_options, division or modulo by zero may results > in undefined behavior. > > Signed-off-by: Sherry Sun > --- > drivers/tty/serial/fsl_lpuart.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c > index 794035041744..777d54b593f8 100644 > --- a/drivers/tty/serial/fsl_lpuart.c > +++ b/drivers/tty/serial/fsl_lpuart.c > @@ -2414,6 +2414,9 @@ lpuart32_console_get_options(struct lpuart_port *sport, int *baud, > > bd = lpuart32_read(&sport->port, UARTBAUD); > bd &= UARTBAUD_SBR_MASK; > + if (!bd) > + return; How can this ever happen? Not to say this is a bad check, but it feels like this can't really happen in real life, what code patch could create this result? And have you tested this on real hardware? thanks, greg k-h