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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 2BD35C43603 for ; Tue, 10 Dec 2019 22:05:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EEFB52053B for ; Tue, 10 Dec 2019 22:05:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576015528; bh=ckVPPKvp4QuzvK5hx8lDOR5XHSzzstdV/oyUR08ezrw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yws2e3O8hzKba9yjoAFj+CVxEfry9PFSQMQogOvv/Sfd4HAoGgBTb3DaGBkntzYu5 eJgI1Ld3MSc2Kw4N+gSub9Lqjc9locMVpywyl1dPHunAH6uDveIJCFkNcMAxYPv/55 ZnH2AJ5m+lEESlxZ71DIJDP2fzZaLraZCx65iT60= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729654AbfLJWF1 (ORCPT ); Tue, 10 Dec 2019 17:05:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:36378 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727659AbfLJWFK (ORCPT ); Tue, 10 Dec 2019 17:05:10 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B2095208C3; Tue, 10 Dec 2019 22:05:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576015509; bh=ckVPPKvp4QuzvK5hx8lDOR5XHSzzstdV/oyUR08ezrw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A1XjJOw6RakFEUnPMmZI4pxWLUkAYuvI+vDBUNaqBdu0uFIxuhJRSGkP/YpbdOh2S YRBHHdlKniH3LwnBKMx7AfPxJAnck7WLyvuMuupGgcqSRHAhUBsXXDOGsGd/6yaNk1 8fd4lDkMNl3/nEUAyMtE6+vnzadn2XD2dNLLL7Vk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Viresh Kumar , Bjorn Andersson , Amit Kucheria , "Rafael J . Wysocki" , Sasha Levin , linux-pm@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 108/130] cpufreq: Register drivers only after CPU devices have been registered Date: Tue, 10 Dec 2019 17:02:39 -0500 Message-Id: <20191210220301.13262-108-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210220301.13262-1-sashal@kernel.org> References: <20191210220301.13262-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 480e8c13567c8..c798a1233e6a0 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2475,6 +2475,13 @@ 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