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=-7.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED 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 A5CADC04EB8 for ; Mon, 10 Dec 2018 21:18:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CE4D2084C for ; Mon, 10 Dec 2018 21:18:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544476715; bh=YWhYiJE4CRyzUEbP6iNgffWEAynq36sTo6lVIxB5xwA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=1BHX0QxE2n3Jx2JOCirRqGnvk3PsGVv5yoh/dorBUVTSzMNeH4TgD+0OkyN0InUte xpvdox4zKRssJv7xh8eLMx2upKw4LY07LoPsnOvLuXkx/WsmiTaOD9eL/5JY+lGCT6 Sj8MK/jYzt3QTodOB+UmC/r8c5I52JpP9aX2DAHk= DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5CE4D2084C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728493AbeLJVSe (ORCPT ); Mon, 10 Dec 2018 16:18:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:59070 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726024AbeLJVSd (ORCPT ); Mon, 10 Dec 2018 16:18:33 -0500 Received: from archlinux (cpc91196-cmbg18-2-0-cust659.5-4.cable.virginm.net [81.96.234.148]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E364D20672; Mon, 10 Dec 2018 21:18:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544476713; bh=YWhYiJE4CRyzUEbP6iNgffWEAynq36sTo6lVIxB5xwA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=cfks1aG/YoNXsA6nxUD7B9YKCMX7u9dfe+y57qBsw71eI/rKDjnIp4QU7xof1hRLU YQKv6jCM3f0jLOBFkevwV4fHYGnP62Ap85bXMht6EhXYbkYgRLM83aR5ZeEd8kZdGP hGiwKyfizmAagF1sS5Xvqff8MkQVqEcNuYmGzGJs= Date: Mon, 10 Dec 2018 21:18:29 +0000 From: Jonathan Cameron To: Martin Kepplinger Cc: knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iio: accel: mma9551_core: prevent using uninitialized variable Message-ID: <20181210211829.44c83cbf@archlinux> In-Reply-To: <20181210142532.15315-1-martink@posteo.de> References: <20181210142532.15315-1-martink@posteo.de> X-Mailer: Claws Mail 3.17.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 10 Dec 2018 15:25:32 +0100 Martin Kepplinger wrote: > mma9551_gpio_config()'s switch statement sets the uninitialized pol_mask > variable but doesn't have default settings. Said function can therefore > be called in a way to use the uninitialized variable (at least in case > enum mma9551_gpio_pin is extended with unhandled values). > > While things should be fine now, this initializes pol_mask just to prevent > failure. I'm unconvinced by this approach. Should the enum be extended and have unhandled values then the value of reg will be garbage as well. I'd much rather see the switch statement have a default with appropriate error return. Jonathan > > Signed-off-by: Martin Kepplinger > --- > drivers/iio/accel/mma9551_core.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/accel/mma9551_core.c b/drivers/iio/accel/mma9551_core.c > index c34c5ce8123b..2fc79b14888b 100644 > --- a/drivers/iio/accel/mma9551_core.c > +++ b/drivers/iio/accel/mma9551_core.c > @@ -539,7 +539,8 @@ EXPORT_SYMBOL(mma9551_update_config_bits); > int mma9551_gpio_config(struct i2c_client *client, enum mma9551_gpio_pin pin, > u8 app_id, u8 bitnum, int polarity) > { > - u8 reg, pol_mask, pol_val; > + u8 reg, pol_val; > + u8 pol_mask = 0; > int ret; > > if (pin > mma9551_gpio_max) {