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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,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 DFFA0C433DB for ; Wed, 24 Mar 2021 16:52:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A270761A12 for ; Wed, 24 Mar 2021 16:52:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236969AbhCXQwZ (ORCPT ); Wed, 24 Mar 2021 12:52:25 -0400 Received: from smtprelay0235.hostedemail.com ([216.40.44.235]:49684 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S237103AbhCXQwQ (ORCPT ); Wed, 24 Mar 2021 12:52:16 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay01.hostedemail.com (Postfix) with ESMTP id D6710100E7B48; Wed, 24 Mar 2021 16:52:14 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: mask89_440a42d2777c X-Filterd-Recvd-Size: 3126 Received: from [192.168.1.159] (unknown [47.151.137.21]) (Authenticated sender: joe@perches.com) by omf07.hostedemail.com (Postfix) with ESMTPA; Wed, 24 Mar 2021 16:52:12 +0000 (UTC) Message-ID: <810d36184b9fa2880d3ba7738a8f182e27f5107b.camel@perches.com> Subject: Re: [PATCH] [v2] drm/imx: imx-ldb: fix out of bounds array access warning From: Joe Perches To: Arnd Bergmann Cc: Philipp Zabel , David Airlie , Daniel Vetter , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Marco Felsch , Laurent Pinchart , Liu Ying , dri-devel , Linux ARM , Linux Kernel Mailing List Date: Wed, 24 Mar 2021 09:52:11 -0700 In-Reply-To: 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 17:42 +0100, Arnd Bergmann wrote: > On Wed, Mar 24, 2021 at 3:20 PM Joe Perches wrote: [] > > > 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. > > Sorry about that. > > I decided against using ERR_PTR() in order to also check for > positive array overflow, but the version I tested was different from > the version I sent. > > v3 coming. Thanks. No worries. Up to you, vsprintf would emit the positive mux as a funky hashed hex value by default if you use ERR_PTR with mux > ARRAY_SIZE so perhaps %d without the ERR_PTR use makes the most sense.