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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, 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_IN_DEF_DKIM_WL 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 41D3EC433ED for ; Mon, 26 Apr 2021 18:18:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05F6661164 for ; Mon, 26 Apr 2021 18:18:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233842AbhDZSTG (ORCPT ); Mon, 26 Apr 2021 14:19:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234221AbhDZSTF (ORCPT ); Mon, 26 Apr 2021 14:19:05 -0400 Received: from mail-yb1-xb2d.google.com (mail-yb1-xb2d.google.com [IPv6:2607:f8b0:4864:20::b2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 061B2C061763 for ; Mon, 26 Apr 2021 11:18:21 -0700 (PDT) Received: by mail-yb1-xb2d.google.com with SMTP id e8so6143199ybq.11 for ; Mon, 26 Apr 2021 11:18:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oxk441iU0wp7QI5uSmMi84qyuJ4uphlRd2RFq20rb5g=; b=fCCr/nw130U0++Z0Ivdh5cPqDkXHWeQsmeWFwQD9nz4NkxrycmLKiQUAFXKoMFlqZx qDEMWDw0v/cbIc0a8goTHlmnrZB6Cn9RHhHgvTC4tYhqM+ZCvQ4MJFU+WNJCkJQnBEW9 bsWQ+775cYJ0vHY8ed/UTIu5IqAqc4WiYqbvI+KLqgY/FdIGxj1oiJVUGM10BKBchfnI kyjf9HUzrbLvG6aI2ZJaPstOkNLsVtLlH7F5hzlfXPUJW3W0YFd8UpigyoHMjBIyaTqK F6s2oJeL1xEhoTLvtbYuIMWxtd/vCEbmbEv7s8sR3KPU8q9xHajibhc49Ror8dMvpOl9 eRjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oxk441iU0wp7QI5uSmMi84qyuJ4uphlRd2RFq20rb5g=; b=TDAT0gQq3GI6rsv1EcY62nw1Zd6jwxtotu0bdBDz+Ye33O6VEWNW2QARxoBqiycLmU +MSbk5Yrpx6tJ3aiao/dVUJod9YZ2vcMNa5QDe7ZwdxB71uAaOmcwweOKitOpVBjwVkW g1OTfaHrShQt+0pA37jyWs9y/Ix1AQGxxOEKVm1zkasAY7eQKJr1CDn2y2TI8JhFy5aK +4VoDvZU0ybYPEwzCS5ZNDMwbmkfjU03SNZK9Yy0RqH/jybpJetkL7fHwUCHdqS04w7W DXC42l9UWn/XvYMWIwCm2vkuOrXl/g+iSdnUlK4kbxiKTqRs4Juyrj/HBa18y0nQMyGc ilNg== X-Gm-Message-State: AOAM5327/5gnFmhMZGsK5pq4TMZYrGEWUa4pmY5FDsV03fTHvaZ//GmF /E2rPqe18+CRZIgf93dHIHMraf5jt+7K++9dNjuOMQ== X-Google-Smtp-Source: ABdhPJxpKkzlxeFeOtzkL9KcfVeos0Z41kgtlmgxKrzK9GddPMejgPaMIQWIl+pLW3jEJCvWSVSH9ek3FFeVdL0Q7Q0= X-Received: by 2002:a25:e7c8:: with SMTP id e191mr24243893ybh.153.1619461100801; Mon, 26 Apr 2021 11:18:20 -0700 (PDT) MIME-Version: 1.0 References: <20210426065618.588144-1-tudor.ambarus@microchip.com> In-Reply-To: <20210426065618.588144-1-tudor.ambarus@microchip.com> From: Saravana Kannan Date: Mon, 26 Apr 2021 11:17:44 -0700 Message-ID: Subject: Re: [PATCH v2] clk: Skip clk provider registration when np is NULL To: Tudor Ambarus Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Michael Turquette , Stephen Boyd , nsaenz@kernel.org, maxime@cerno.tech, Kevin Hilman , Ulf Hansson , "Brown, Len" , Pavel Machek , Rob Herring , Frank Rowand , Marc Zyngier , Thomas Gleixner , Geert Uytterhoeven , Nicolas Saenz Julienne , Guenter Roeck , guillaume.tucker@collabora.com, linux-clk , LKML , Jonathan Corbet , Nicolas Ferre , Claudiu Beznea , Linux Doc Mailing List , Linux PM , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , ACPI Devel Maling List , Android Kernel Team , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS , ACPI Devel Maling List , Android Kernel Team , linux-rpi-kernel" , Marek Szyprowski Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Sun, Apr 25, 2021 at 11:56 PM Tudor Ambarus wrote: > > commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added") > revealed that clk/bcm/clk-raspberrypi.c driver calls > devm_of_clk_add_hw_provider(), with a NULL dev->of_node, which resulted in a > NULL pointer dereference in of_clk_add_hw_provider() when calling > fwnode_dev_initialized(). > > Returning 0 is reducing the if conditions in driver code and is being > consistent with the CONFIG_OF=n inline stub that returns 0 when CONFIG_OF > is disabled. The downside is that drivers will maybe register clkdev lookups > when they don't need to and waste some memory. > > Reported-by: Marek Szyprowski > Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added") > Fixes: 3c9ea42802a1 ("clk: Mark fwnodes when their clock provider is added/removed") > Signed-off-by: Tudor Ambarus > Reviewed-by: Stephen Boyd > --- Reviewed-by: Saravana Kannan -Saravana > v2: > - s/return 0;/return; in void of_clk_del_provider() > - add second fixes tag and Stephen's R-b tag > The opinions on whether to return an error or zero were split. Returning 0 > and skipping the logic was considered safer as we don't know for sure if > other drivers are affected. See: > https://lore.kernel.org/lkml/d24bebc5-0f78-021f-293f-e58defa32531@samsung.com/ > https://lore.kernel.org/lkml/20210423171335.262316-1-tudor.ambarus@microchip.com/ > > drivers/clk/clk.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index a3b30f7de2ef..b47460b40d14 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c > @@ -4552,6 +4552,9 @@ int of_clk_add_provider(struct device_node *np, > struct of_clk_provider *cp; > int ret; > > + if (!np) > + return 0; > + > cp = kzalloc(sizeof(*cp), GFP_KERNEL); > if (!cp) > return -ENOMEM; > @@ -4591,6 +4594,9 @@ int of_clk_add_hw_provider(struct device_node *np, > struct of_clk_provider *cp; > int ret; > > + if (!np) > + return 0; > + > cp = kzalloc(sizeof(*cp), GFP_KERNEL); > if (!cp) > return -ENOMEM; > @@ -4688,6 +4694,9 @@ void of_clk_del_provider(struct device_node *np) > { > struct of_clk_provider *cp; > > + if (!np) > + return; > + > mutex_lock(&of_clk_mutex); > list_for_each_entry(cp, &of_clk_providers, link) { > if (cp->node == np) { > -- > 2.25.1 >