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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 18945C433E0 for ; Wed, 24 Mar 2021 14:21:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D721361A07 for ; Wed, 24 Mar 2021 14:21:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236165AbhCXOVE (ORCPT ); Wed, 24 Mar 2021 10:21:04 -0400 Received: from smtprelay0195.hostedemail.com ([216.40.44.195]:59940 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S236123AbhCXOU3 (ORCPT ); Wed, 24 Mar 2021 10:20:29 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay02.hostedemail.com (Postfix) with ESMTP id E3CBF8406; Wed, 24 Mar 2021 14:20:27 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: mist41_450a56a2777b X-Filterd-Recvd-Size: 3203 Received: from [192.168.1.159] (unknown [47.151.137.21]) (Authenticated sender: joe@perches.com) by omf11.hostedemail.com (Postfix) with ESMTPA; Wed, 24 Mar 2021 14:20:25 +0000 (UTC) Message-ID: Subject: Re: [PATCH] [v2] drm/imx: imx-ldb: fix out of bounds array access warning From: Joe Perches To: Arnd Bergmann , Philipp Zabel , David Airlie , Daniel Vetter Cc: Arnd Bergmann , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Marco Felsch , Laurent Pinchart , Liu Ying , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Date: Wed, 24 Mar 2021 07:20:23 -0700 In-Reply-To: <20210324121832.3714570-1-arnd@kernel.org> References: <20210324121832.3714570-1-arnd@kernel.org> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.1-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2021-03-24 at 13:17 +0100, Arnd Bergmann wrote: > From: Arnd Bergmann > > When CONFIG_OF is disabled, building with 'make W=1' produces warnings > about out of bounds array access: > > drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop': > drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below array bounds of 'struct clk *[4]' [-Werror=array-bounds] > > Add an error check before the index is used, which helps with the > warning, as well as any possible other error condition that may be > triggered at runtime. > > The warning could be fixed by adding a Kconfig depedency on CONFIG_OF, > but Liu Ying points out that the driver may hit the out-of-bounds > problem at runtime anyway. > > Signed-off-by: Arnd Bergmann > --- > v2: fix subject line >     expand patch description >     print mux number >     check upper bound as well [] > diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c [] > @@ -197,6 +197,12 @@ static void imx_ldb_encoder_enable(struct drm_encoder *encoder) >   int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN; >   int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder); > > + if (mux < 0 || mux >= ARRAY_SIZE(ldb->clk_sel)) { > + dev_warn(ldb->dev, "%s: invalid mux %d\n", > + __func__, ERR_PTR(mux)); This does not compile without warnings. drivers/gpu/drm/imx/imx-ldb.c: In function ‘imx_ldb_encoder_enable’: drivers/gpu/drm/imx/imx-ldb.c:201:22: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘void *’ [-Wformat=] 201 | dev_warn(ldb->dev, "%s: invalid mux %d\n", | ^~~~~~~~~~~~~~~~~~~~~~ If you want to use ERR_PTR, the %d should be %pe as ERR_PTR is converting an int a void * to decode the error type and emit it as a string.