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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 49A14C2D0CE for ; Sun, 29 Dec 2019 17:34:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2292B21744 for ; Sun, 29 Dec 2019 17:34:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577640842; bh=lpKrn/z464txxM/CiCqCNfrmIYaLTF+arTlZnHGXzXM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=NPiTyjqjOWCEuhzxpRc+gntwAtIsQjgCagOiRzaMpNU8OGiGUmq/p/QmMiXmCIFfE +Y3aO7158ELnveG0CYQaf+ICPr5A9OVj0EJ5WAkabLted6EWDynE0o0xN8ZpFuB+aL NWsoEdIMPDkRCFlxdoZfgcme13MkHJqW1KEGLeJU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729562AbfL2ReB (ORCPT ); Sun, 29 Dec 2019 12:34:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:36416 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729535AbfL2Rd6 (ORCPT ); Sun, 29 Dec 2019 12:33:58 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2F92520722; Sun, 29 Dec 2019 17:33:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577640837; bh=lpKrn/z464txxM/CiCqCNfrmIYaLTF+arTlZnHGXzXM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZeuWt3MXlpKOFg5O2eeQVYsTrk4Per7vayrFJscRDlZepxTqE/hYtp/4JN3F32nlN PRPtfzXUr7GyRJYXThqw0m+/uGU9Cy/erYYhZTA8gq9pUbl9m1CjMhnbniwsG+ZTIh j6fdtgtFrf5+r+Qr3FHPI4Ey2sUNfI8/CMApr3PI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bjorn Andersson , Viresh Kumar , Amit Kucheria , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 4.19 158/219] cpufreq: Register drivers only after CPU devices have been registered Date: Sun, 29 Dec 2019 18:19:20 +0100 Message-Id: <20191229162532.386006575@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191229162508.458551679@linuxfoundation.org> References: <20191229162508.458551679@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Viresh Kumar [ Upstream commit 46770be0cf94149ca48be87719bda1d951066644 ] The cpufreq core heavily depends on the availability of the struct device for CPUs and if they aren't available at the time cpufreq driver is registered, we will never succeed in making cpufreq work. This happens due to following sequence of events: - cpufreq_register_driver() - subsys_interface_register() - return 0; //successful registration of driver ... at a later point of time - register_cpu(); - device_register(); - bus_probe_device(); - sif->add_dev(); - cpufreq_add_dev(); - get_cpu_device(); //FAILS - per_cpu(cpu_sys_devices, num) = &cpu->dev; //used by get_cpu_device() - return 0; //CPU registered successfully Because the per-cpu variable cpu_sys_devices is set only after the CPU device is regsitered, cpufreq will never be able to get it when cpufreq_add_dev() is called. This patch avoids this failure by making sure device structure of at least CPU0 is available when the cpufreq driver is registered, else return -EPROBE_DEFER. Reported-by: Bjorn Andersson Co-developed-by: Amit Kucheria Signed-off-by: Viresh Kumar Tested-by: Amit Kucheria Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/cpufreq/cpufreq.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 9d8d64f706e0..e35c397b1259 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2480,6 +2480,13 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) if (cpufreq_disabled()) return -ENODEV; + /* + * The cpufreq core depends heavily on the availability of device + * structure, make sure they are available before proceeding further. + */ + if (!get_cpu_device(0)) + return -EPROBE_DEFER; + if (!driver_data || !driver_data->verify || !driver_data->init || !(driver_data->setpolicy || driver_data->target_index || driver_data->target) || -- 2.20.1