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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 AF2B4C001E8 for ; Mon, 12 Apr 2021 09:18:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 841566120F for ; Mon, 12 Apr 2021 09:18:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241720AbhDLJRG (ORCPT ); Mon, 12 Apr 2021 05:17:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:48564 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239174AbhDLI7V (ORCPT ); Mon, 12 Apr 2021 04:59:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3109961371; Mon, 12 Apr 2021 08:57:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618217864; bh=2OiiOVcCTU3XpXSCdprFOXNXHAcDfrim01pwqjNTx6Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E24JCkQisoBrhix0TDeY+chVNbNLVMVCi5tK31amcu8B7wIBq73WQJIVcE5PR6Qxj Vc8B0cnnoCKAaADzxSiPKvVR4y6hIbcoaFVTzbEridRVCroX28UmKrMY+RzE6+MrOr 9nuNQKgVKSh6295gGCt2UCYXXVgPqNBvBiLr/ZaA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dmitry Baryshkov , Fabio Estevam , Krishna Manikandan , Stephen Boyd , Rob Clark , Sasha Levin Subject: [PATCH 5.10 139/188] drm/msm: Set drvdata to NULL when msm_drm_init() fails Date: Mon, 12 Apr 2021 10:40:53 +0200 Message-Id: <20210412084018.259747917@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084013.643370347@linuxfoundation.org> References: <20210412084013.643370347@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stephen Boyd [ Upstream commit 5620b135aea49a8f41c86aaecfcb1598a7774121 ] We should set the platform device's driver data to NULL here so that code doesn't assume the struct drm_device pointer is valid when it could have been destroyed. The lifetime of this pointer is managed by a kref but when msm_drm_init() fails we call drm_dev_put() on the pointer which will free the pointer's memory. This driver uses the component model, so there's sort of two "probes" in this file, one for the platform device i.e. msm_pdev_probe() and one for the component i.e. msm_drm_bind(). The msm_drm_bind() code is using the platform device's driver data to store struct drm_device so the two functions are intertwined. This relationship becomes a problem for msm_pdev_shutdown() when it tests the NULL-ness of the pointer to see if it should call drm_atomic_helper_shutdown(). The NULL test is a proxy check for if the pointer has been freed by kref_put(). If the drm_device has been destroyed, then we shouldn't call the shutdown helper, and we know that is the case if msm_drm_init() failed, therefore set the driver data to NULL so that this pointer liveness is tracked properly. Fixes: 9d5cbf5fe46e ("drm/msm: add shutdown support for display platform_driver") Cc: Dmitry Baryshkov Cc: Fabio Estevam Cc: Krishna Manikandan Signed-off-by: Stephen Boyd Message-Id: <20210325212822.3663144-1-swboyd@chromium.org> Signed-off-by: Rob Clark Signed-off-by: Sasha Levin --- drivers/gpu/drm/msm/msm_drv.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index b38ebccad42f..0aacc43faefa 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -557,6 +557,7 @@ err_free_priv: kfree(priv); err_put_drm_dev: drm_dev_put(ddev); + platform_set_drvdata(pdev, NULL); return ret; } -- 2.30.2