From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752608AbaKXJIV (ORCPT ); Mon, 24 Nov 2014 04:08:21 -0500 Received: from mail-wg0-f43.google.com ([74.125.82.43]:45539 "EHLO mail-wg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750834AbaKXJIT (ORCPT ); Mon, 24 Nov 2014 04:08:19 -0500 From: Tomeu Vizoso To: linux-pm@vger.kernel.org Cc: Javier Martinez Canillas , Tomeu Vizoso , "Rafael J. Wysocki" , Viresh Kumar , linux-kernel@vger.kernel.org Subject: [PATCH v2] cpufreq: Ref the policy object sooner Date: Mon, 24 Nov 2014 10:08:03 +0100 Message-Id: <1416820083-20902-1-git-send-email-tomeu.vizoso@collabora.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Do it before it's assigned to cpufreq_cpu_data, otherwise when a driver tries to get the cpu frequency during initialization the policy kobj is referenced and we get this warning: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 64 at include/linux/kref.h:47 kobject_get+0x64/0x70() Modules linked in: CPU: 1 PID: 64 Comm: irq/77-tegra-ac Not tainted 3.18.0-rc4-next-20141114ccu-00050-g3eff942 #326 [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0x98/0xd8) [] (dump_stack) from [] (warn_slowpath_common+0x84/0xb4) [] (warn_slowpath_common) from [] (warn_slowpath_null+0x1c/0x24) [] (warn_slowpath_null) from [] (kobject_get+0x64/0x70) [] (kobject_get) from [] (cpufreq_cpu_get+0x88/0xc8) [] (cpufreq_cpu_get) from [] (cpufreq_get+0xc/0x64) [] (cpufreq_get) from [] (actmon_thread_isr+0x134/0x198) [] (actmon_thread_isr) from [] (irq_thread_fn+0x1c/0x40) [] (irq_thread_fn) from [] (irq_thread+0x134/0x174) [] (irq_thread) from [] (kthread+0xdc/0xf4) [] (kthread) from [] (ret_from_fork+0x14/0x3c) ---[ end trace b7bd64a81b340c59 ]--- Signed-off-by: Tomeu Vizoso --- v2: * Properly unwind when erroring out. --- drivers/cpufreq/cpufreq.c | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 4473eba..ae27ea6 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -898,46 +898,31 @@ static int cpufreq_add_dev_interface(struct cpufreq_policy *policy, struct freq_attr **drv_attr; int ret = 0; - /* prepare interface data */ - ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, - &dev->kobj, "cpufreq"); - if (ret) - return ret; - /* set up files for this cpu device */ drv_attr = cpufreq_driver->attr; while ((drv_attr) && (*drv_attr)) { ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); if (ret) - goto err_out_kobj_put; + return ret; drv_attr++; } if (cpufreq_driver->get) { ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); if (ret) - goto err_out_kobj_put; + return ret; } ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); if (ret) - goto err_out_kobj_put; + return ret; if (cpufreq_driver->bios_limit) { ret = sysfs_create_file(&policy->kobj, &bios_limit.attr); if (ret) - goto err_out_kobj_put; + return ret; } - ret = cpufreq_add_dev_symlink(policy); - if (ret) - goto err_out_kobj_put; - - return ret; - -err_out_kobj_put: - kobject_put(&policy->kobj); - wait_for_completion(&policy->kobj_unregister); - return ret; + return cpufreq_add_dev_symlink(policy); } static void cpufreq_init_policy(struct cpufreq_policy *policy) @@ -1196,6 +1181,8 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) goto err_set_policy_cpu; } + down_write(&policy->rwsem); + /* related cpus should atleast have policy->cpus */ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); @@ -1208,9 +1195,17 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) if (!recover_policy) { policy->user_policy.min = policy->min; policy->user_policy.max = policy->max; + + /* prepare interface data */ + ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, + &dev->kobj, "cpufreq"); + if (ret) { + pr_err("%s: failed to init policy->kobj: %d\n", + __func__, ret); + goto err_init_policy_kobj; + } } - down_write(&policy->rwsem); write_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu(j, policy->cpus) per_cpu(cpufreq_cpu_data, j) = policy; @@ -1301,6 +1296,11 @@ err_get_freq: per_cpu(cpufreq_cpu_data, j) = NULL; write_unlock_irqrestore(&cpufreq_driver_lock, flags); + if (!recover_policy) { + kobject_put(&policy->kobj); + wait_for_completion(&policy->kobj_unregister); + } +err_init_policy_kobj: up_write(&policy->rwsem); if (cpufreq_driver->exit) -- 1.9.3