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=ham 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 D348DC43603 for ; Tue, 10 Dec 2019 21:38:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A083A2073B for ; Tue, 10 Dec 2019 21:38:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576013903; bh=vACwuEckSbbcXg5RDmsmQNirCql0qClr/29nJu35mGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dl1Lm36YHo0ihe4pNiuMtIto/Bq0bWBolQv4w1kci3VikbFI0xjlcnPZd3YPYHBL9 sAMPo7x/JSWhgaAEHqRJwSVuwTOMnWGBUl0bhec0FB+JjFPgv+hda14fO7nM/flrfV Z93rkxszKB2zgAwmfqOoTbrRfEeFPMe5gofAQNJY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729276AbfLJViW (ORCPT ); Tue, 10 Dec 2019 16:38:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:40920 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730220AbfLJVfR (ORCPT ); Tue, 10 Dec 2019 16:35:17 -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 120C4207FF; Tue, 10 Dec 2019 21:35:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576013716; bh=vACwuEckSbbcXg5RDmsmQNirCql0qClr/29nJu35mGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tJ2CPdVps4dXcDMAj1FQZQKNYS5LPPGiDQzU0NOT7rp5CAZUCrKKzJWk3BY6/KHT0 7aXmwKu1vsLhCSGWRZvuLoi844T8rEedCeBLcs5AYJOpQqGZr5MDk6Nqv0oklvpqwB e7kUFeSZosqY8Xkq2u1h5PN5inwr+1WBJ86gfZ+I= 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 4.19 144/177] cpufreq: Register drivers only after CPU devices have been registered Date: Tue, 10 Dec 2019 16:31:48 -0500 Message-Id: <20191210213221.11921-144-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210213221.11921-1-sashal@kernel.org> References: <20191210213221.11921-1-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 9d8d64f706e06..e35c397b1259f 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