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 BEBECC43603 for ; Tue, 10 Dec 2019 22:34:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91149207FF for ; Tue, 10 Dec 2019 22:34:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576017282; bh=x9I7T5T7xIgdzAY+wPHiDtGNSoQ7jwk2khFKjd709c4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mjVNBwtdfqBqKlg9XW2m5la30UWXj22Il7adHVDF+NW1F1FSg25z7lxWuOkdc78TH WSeKq1dCgBfswrCrSpuwHD3yW1x2FMu73ObUfQgdMiJI5+8TZ1vYY7RGOvlm2GKSFB bC5bjOx9UAQsYgECLNhv+NbAnlFYspxvVQveu6Do= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727317AbfLJWek (ORCPT ); Tue, 10 Dec 2019 17:34:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:55834 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730314AbfLJWe0 (ORCPT ); Tue, 10 Dec 2019 17:34:26 -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 4D931207FF; Tue, 10 Dec 2019 22:34:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576017266; bh=x9I7T5T7xIgdzAY+wPHiDtGNSoQ7jwk2khFKjd709c4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wDOjGTiT/J53Tn8XztpwjRoUmnhXQVNBfgLjmFn8xYIdxsGVDrRkVxAUH3Re+wZna uO2Mk6K1bHwmktyr3+vr3yF3jX3CbXivtHBE4LOH+Y3Qoe4BR/e7vQB26BZSYJQEvZ slx/D93Tety0auKclZFU0aGcY9QNtwxRdp8THB+4= 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 4.4 59/71] cpufreq: Register drivers only after CPU devices have been registered Date: Tue, 10 Dec 2019 17:33:04 -0500 Message-Id: <20191210223316.14988-59-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210223316.14988-1-sashal@kernel.org> References: <20191210223316.14988-1-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 2239d42bdadd9..49aa58e617db4 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2426,6 +2426,13 @@ 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