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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 DC869C43460 for ; Mon, 10 May 2021 20:20:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B915F61432 for ; Mon, 10 May 2021 20:20:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232013AbhEJUVz (ORCPT ); Mon, 10 May 2021 16:21:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:43348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229566AbhEJUVx (ORCPT ); Mon, 10 May 2021 16:21:53 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 94A36613C4; Mon, 10 May 2021 20:20:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620678048; bh=NnI6Jar/M7IdxLtxsAWt4IwLrWaSY6o6+asG73lwypk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=p2hJI9M83cDG45oqbIlVUmrDpuGSgTqB+rZgiTLQy5ADDbE7geoZmjUIYljGm50RU 9gd5JGSGKWBoSz8eqe/8nso7itp0CL1VLUdZVpFJbtUwUsRTRWMTfTYgZwfNxxllNc StwmKEjeAsTcOFbJvKO0TQRH86N2tlNuoBX98XpgLV5KDfPYLIkssGqez7lQ/dLqn8 t4vUQ4KtvWWxucZOLo1aQfy+YnSFI8f0XUkPTGjnt4IwpYdznHXj9I2TWF7VUoLaNT bFRwIZy6GyhzjWr8KCS63nd6m8DxWLwP9kJ2mbA7EkhKyFYVTD5Tso8Vb90VC/NTsi 9DANZXpaUwlDA== Date: Mon, 10 May 2021 13:20:39 -0700 From: Nathan Chancellor To: Tudor Ambarus Cc: gregkh@linuxfoundation.org, rafael@kernel.org, mturquette@baylibre.com, sboyd@kernel.org, nsaenz@kernel.org, maxime@cerno.tech, khilman@kernel.org, ulf.hansson@linaro.org, len.brown@intel.com, pavel@ucw.cz, robh+dt@kernel.org, frowand.list@gmail.com, maz@kernel.org, tglx@linutronix.de, saravanak@google.com, geert@linux-m68k.org, nsaenzjulienne@suse.de, linux@roeck-us.net, guillaume.tucker@collabora.com, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, corbet@lwn.net, nicolas.ferre@microchip.com, claudiu.beznea@microchip.com, linux-doc@vger.kernel.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-acpi@vger.kernel.org, kernel-team@android.com, linux-rpi-kernel@lists.infradead.org, Marek Szyprowski Subject: Re: [PATCH v2] clk: Skip clk provider registration when np is NULL Message-ID: References: <20210426065618.588144-1-tudor.ambarus@microchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210426065618.588144-1-tudor.ambarus@microchip.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Mon, Apr 26, 2021 at 09:56:18AM +0300, 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 Tested-by: Nathan Chancellor > --- > 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 >