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 33744C4338F for ; Wed, 28 Jul 2021 07:27:13 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E271D60EB9 for ; Wed, 28 Jul 2021 07:27:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E271D60EB9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ravnborg.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 777496E1E8; Wed, 28 Jul 2021 07:27:12 +0000 (UTC) Received: from mx1.smtp.larsendata.com (mx1.smtp.larsendata.com [91.221.196.215]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6D3FC6E1E8 for ; Wed, 28 Jul 2021 07:27:11 +0000 (UTC) Received: from mail01.mxhotel.dk (mail01.mxhotel.dk [91.221.196.236]) by mx1.smtp.larsendata.com (Halon) with ESMTPS id 3c52e2c1-ef75-11eb-9082-0050568c148b; Wed, 28 Jul 2021 07:27:16 +0000 (UTC) Received: from ravnborg.org (80-162-45-141-cable.dk.customer.tdc.net [80.162.45.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: sam@ravnborg.org) by mail01.mxhotel.dk (Postfix) with ESMTPSA id A3EBA194B99; Wed, 28 Jul 2021 09:27:30 +0200 (CEST) Date: Wed, 28 Jul 2021 09:27:07 +0200 X-Report-Abuse-To: abuse@mxhotel.dk From: Sam Ravnborg To: Anitha Chrisanthus Subject: Re: [PATCH 12/14] drm/kmb: Fix possible oops in error handling Message-ID: References: <20210728003126.1425028-1-anitha.chrisanthus@intel.com> <20210728003126.1425028-12-anitha.chrisanthus@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210728003126.1425028-12-anitha.chrisanthus@intel.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: edmund.j.dea@intel.com, Dan Carpenter , dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Anitha, On Tue, Jul 27, 2021 at 05:31:24PM -0700, Anitha Chrisanthus wrote: > If kmb_dsi_init() fails the "kmb->kmb_dsi" variable is an error pointer. > This can potentially result in kernel panic when kmb_dsi_host_unregister is > called. > > Fixes: 7f7b96a8a0a1 ("drm/kmb: Add support for KeemBay Display") > Fixes: 98521f4d4b4c ("drm/kmb: Mipi DSI part of the display driver") > Cc: Dan Carpenter > Signed-off-by: Anitha Chrisanthus > --- > drivers/gpu/drm/kmb/kmb_drv.c | 9 ++++++--- > drivers/gpu/drm/kmb/kmb_dsi.c | 9 +++++---- > drivers/gpu/drm/kmb/kmb_dsi.h | 3 ++- > 3 files changed, 13 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/kmb/kmb_drv.c b/drivers/gpu/drm/kmb/kmb_drv.c > index bb7eca9e13ae..12f35c43d838 100644 > --- a/drivers/gpu/drm/kmb/kmb_drv.c > +++ b/drivers/gpu/drm/kmb/kmb_drv.c > @@ -454,8 +454,9 @@ static int kmb_remove(struct platform_device *pdev) > dev_set_drvdata(dev, NULL); > > /* Unregister DSI host */ > - kmb_dsi_host_unregister(kmb->kmb_dsi); > + kmb_dsi_host_unregister(); > drm_atomic_helper_shutdown(drm); > + drm_dev_put(drm); > return 0; > } > > @@ -519,7 +520,7 @@ static int kmb_probe(struct platform_device *pdev) > if (IS_ERR(kmb->kmb_dsi)) { > drm_err(&kmb->drm, "failed to initialize DSI\n"); > ret = PTR_ERR(kmb->kmb_dsi); > - goto err_free1; > + goto err_free2; > } > > kmb->kmb_dsi->dev = &dsi_pdev->dev; > @@ -555,8 +556,10 @@ static int kmb_probe(struct platform_device *pdev) > drm_crtc_cleanup(&kmb->crtc); > drm_mode_config_cleanup(&kmb->drm); > err_free1: > + kmb_dsi_clk_disable(kmb->kmb_dsi); > + err_free2: > dev_set_drvdata(dev, NULL); > - kmb_dsi_host_unregister(kmb->kmb_dsi); > + kmb_dsi_host_unregister(); > This really looks like a step backward. There should not be a eed to call unregister if kmb_dsi is not a valid pointer in the first place. Also drn_dev_put() should not be needed with the use of drmm infrastructure. > return ret; > } > diff --git a/drivers/gpu/drm/kmb/kmb_dsi.c b/drivers/gpu/drm/kmb/kmb_dsi.c > index 1cca0fe6f35f..a500172ada87 100644 > --- a/drivers/gpu/drm/kmb/kmb_dsi.c > +++ b/drivers/gpu/drm/kmb/kmb_dsi.c > @@ -172,17 +172,17 @@ mipi_hs_freq_range[MIPI_DPHY_DEFAULT_BIT_RATES] = { > {.default_bit_rate_mbps = 2500, .hsfreqrange_code = 0x49} > }; > > -static void kmb_dsi_clk_disable(struct kmb_dsi *kmb_dsi) > +void kmb_dsi_clk_disable(struct kmb_dsi *kmb_dsi) > { > clk_disable_unprepare(kmb_dsi->clk_mipi); > clk_disable_unprepare(kmb_dsi->clk_mipi_ecfg); > clk_disable_unprepare(kmb_dsi->clk_mipi_cfg); > } > > -void kmb_dsi_host_unregister(struct kmb_dsi *kmb_dsi) > +void kmb_dsi_host_unregister(void) > { > - kmb_dsi_clk_disable(kmb_dsi); > - mipi_dsi_host_unregister(kmb_dsi->host); > + if (dsi_host) > + mipi_dsi_host_unregister(dsi_host); > } I thought we had killed the global dsi_host variable?? Seems some cleanup is till needed here. Sam