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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AE678C433F5 for ; Fri, 21 Jan 2022 13:30:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Z1WJS6IwzxAc+kEO14alwbKa9xB5ylpzGlKn2B04gGw=; b=a3vIa3u3+OCj8b LBef9IaDSMJIC2qsFudM9fleg6GqRDSG4A0gSG6mBbIMJIEYddCIKABla0nwzqcp5zKfPI2MMHgXw cxpOBtxrFnVlO3nqZTkwDlPay1vQE3o4onxxmNhV+US8FMU8l5ewL6128IGGQs1tvJRUjOWZ6TV/M sAhx0yfH2veH7uavBXfzNisxL4vmKXo4LaGfk5uOmT1MRYDAvxHfvg5icNCshTmgdXlO/Dg62gyTb kVeLT6y5tE6S785x/Cp6LBoh/a3E0amHq+2+CC0EGj+rQtxIx+vXz11fwx9/U8CzEwue3mlJhDoeS YEBYwuFL5bUGUWcdER6g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nAtyH-00FAEn-TQ; Fri, 21 Jan 2022 13:28:54 +0000 Received: from phobos.denx.de ([2a01:238:438b:c500:173d:9f52:ddab:ee01]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nAtyB-00FACG-Fv for linux-arm-kernel@lists.infradead.org; Fri, 21 Jan 2022 13:28:50 +0000 Received: from [127.0.0.1] (p578adb1c.dip0.t-ipconnect.de [87.138.219.28]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id 6755B80FE1; Fri, 21 Jan 2022 14:28:45 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1642771726; bh=+vQdfU2JkINR+WOEonZ1XBYtiZUhavjnNuh9FSJugW8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=tpppOmobNR7k1qnWsY9x+K3cV8HaUVAnsVMWtZZtPonJKRjJdp8Y2uek1gPqWv4vi v+Y1i8pg+Z3ttVZ3gRwZneiOC523B4G4rPKw54cC2xbkRfzL/DqDJatJ62pUl4xR64 lI+bjCK9hf9UKbes15yvpmhQ+O17RZoQiTGIVbUSqITRNHsIXERH6KLaTv3aUyrbrA 98Jx5+B+q8zFNlWgks1g5/YZyollMDfJb4i3G5+HQsOd21SKM1NKE/5E3t9p2VTGiB qGgrvuIvSMZ+0fNQ1mXERudBGduGpYjj/Xg0UmwSlohlK2IKc7myPhwFfncYtQ/VBG TwYC/TraIjfiw== Message-ID: <9b71782f-a54f-9323-ffd8-141dfe5e875e@denx.de> Date: Fri, 21 Jan 2022 14:28:44 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: (EXT) Re: [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference Content-Language: en-US To: Alexander Stein , Stefan Agner , David Airlie , Daniel Vetter , Shawn Guo , Sascha Hauer , Fabio Estevam , Laurent Pinchart Cc: linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org References: <20220121131238.507567-1-alexander.stein@ew.tq-group.com> <4d3654b5-9a87-1c02-f2d9-d0974e628c20@denx.de> <2361278.ElGaqSPkdT@steina-w> From: Marek Vasut In-Reply-To: <2361278.ElGaqSPkdT@steina-w> X-Virus-Scanned: clamav-milter 0.103.5 at phobos.denx.de X-Virus-Status: Clean X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220121_052847_893178_E25719E9 X-CRM114-Status: GOOD ( 21.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 1/21/22 14:24, Alexander Stein wrote: > Am Freitag, 21. Januar 2022, 14:14:01 CET schrieb Marek Vasut: >> On 1/21/22 14:12, Alexander Stein wrote: >>> Do not deference the NULL pointer if the bridge does not return a >>> bridge state. Assume a fixed format instead. >>> >>> Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest >>> bridge if present") Signed-off-by: Alexander Stein >>> >>> --- >>> This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached >>> to it. atomic_get_input_bus_fmts is only implemented for the >>> lvds-decoder case. >>> >>> drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++- >>> 1 file changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c >>> b/drivers/gpu/drm/mxsfb/mxsfb_kms.c index 0655582ae8ed..4cfb6c001679 >>> 100644 >>> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c >>> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c >>> @@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc >>> *crtc,> >>> bridge_state = >>> >>> drm_atomic_get_new_bridge_state(state, >>> >>> > mxsfb->bridge); >>> >>> - bus_format = bridge_state->input_bus_cfg.format; >>> + if (!bridge_state) >>> + bus_format = MEDIA_BUS_FMT_FIXED; >>> + else >>> + bus_format = bridge_state- >> input_bus_cfg.format; >>> + >>> >>> if (bus_format == MEDIA_BUS_FMT_FIXED) { >>> >>> dev_warn_once(drm->dev, >>> >>> "Bridge does not provide bus > format, assuming >>> MEDIA_BUS_FMT_RGB888_1X24. > \n" >> >> Shouldn't this be fixed on the bridge driver side instead ? >> >> Which bridge driver do you use ? > > It's drivers/gpu/drm/bridge/lvds-codec.c. I thought naming the compatibles > would suffice. I consider a patch for the bridge driver as a separate issue, > hence the warning from mxsfb. Although I'm unsure how/what to implement. > Similar to the encode case where the bus format is specified in DT? I'm sorry, I missed the lvds-codec part. Laurent is already on CC. > Anyway, mxsfb should not never dereference the NULL pointer which > drm_atomic_get_new_bridge_state is allowed to return. That line ^ should be in the commit message. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel