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=-19.0 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, URIBL_BLOCKED,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 0016DC433C1 for ; Thu, 25 Mar 2021 21:29:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD815619FF for ; Thu, 25 Mar 2021 21:29:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231138AbhCYV2h (ORCPT ); Thu, 25 Mar 2021 17:28:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231322AbhCYV2Z (ORCPT ); Thu, 25 Mar 2021 17:28:25 -0400 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67EB3C06174A for ; Thu, 25 Mar 2021 14:28:24 -0700 (PDT) Received: by mail-pf1-x42a.google.com with SMTP id q5so3361649pfh.10 for ; Thu, 25 Mar 2021 14:28:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Ar68jm2yqLLP/HtYyEXI6uh/AJB1y8cS7PMCnpcIT0Y=; b=TEhkRsQE/1x3MCeVcTv1S4X5n9NVnMa/jFa1XAMbvGy39rpRV1ols2bNLEAqx+w+h5 g2Q8Cf5S/EzPjEVGrOQzwY+XfoaFuzar68pfaJd/vxur40Pn9WtqXa1pHKYOkFb2L6Ii ZRPcqJ7LOVPXZga+/NH+evnqAMK2sye1eGuMg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Ar68jm2yqLLP/HtYyEXI6uh/AJB1y8cS7PMCnpcIT0Y=; b=TgJabAKcQXnrX7C/IcNGiAjrh0XKZGn1w7KuI736YQrJ0j8nJw/9MoX91D0sy3x739 AFScmNoJlHG/azjqyRTbMwsbfq1w6jGalpGblo9uCQQlKQ9PHyWGzMKAtw22pH5mvNKb BhsSh/4liyBMbAPDCveCc1nbR7v9nlCDEaVrDL48q181sRfKB0V8f4aqUIlfrUql7NGT t1dFCr56OzLnxyULk6UsL2H9V5KFyunjngGGTSEhPxcSXeHm7qB14YHofdU7JvK4osHP Hkbwb2S3ck6go0MbXA3nGfYttMTviq/LDjgb7da2NaRwi6QbX9H49ANFKbAQJCx2j5n2 PnxQ== X-Gm-Message-State: AOAM532Fu3H2ymFDWYJhnLodt4CioLEV5JTXHrVdJa5x49h5p6HoUE+m mRNjXkTKZkwMEIPlY7uDIe0TeA== X-Google-Smtp-Source: ABdhPJxb+M1K271yeV8ZJZrouwWTafpUJhJVRUBFQFGmitdZRBmwSGYAIxMD8Z4uVYOLg333mONJ/Q== X-Received: by 2002:a17:902:dad2:b029:e5:e7da:cbb0 with SMTP id q18-20020a170902dad2b02900e5e7dacbb0mr11705640plx.66.1616707703977; Thu, 25 Mar 2021 14:28:23 -0700 (PDT) Received: from smtp.gmail.com ([2620:15c:202:201:18a3:238:26c5:1521]) by smtp.gmail.com with ESMTPSA id e21sm5880792pgv.74.2021.03.25.14.28.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Mar 2021 14:28:23 -0700 (PDT) From: Stephen Boyd To: Rob Clark , Sean Paul Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, Dmitry Baryshkov , Fabio Estevam , Krishna Manikandan Subject: [PATCH] drm/msm: Set drvdata to NULL when msm_drm_init() fails Date: Thu, 25 Mar 2021 14:28:22 -0700 Message-Id: <20210325212822.3663144-1-swboyd@chromium.org> X-Mailer: git-send-email 2.31.0.291.g576ba9dcdaf-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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 --- 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 a5c6b8c23336..196907689c82 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -570,6 +570,7 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv) kfree(priv); err_put_drm_dev: drm_dev_put(ddev); + platform_set_drvdata(pdev, NULL); return ret; } -- https://chromeos.dev