From: Tomeu Vizoso tomeu.vizoso@collabora.com

Upstream commit id: 6d4e81ed89c0

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 [<c0016fac>] (unwind_backtrace) from [<c001272c>] (show_stack+0x10/0x14) [<c001272c>] (show_stack) from [<c06085d8>] (dump_stack+0x98/0xd8) [<c06085d8>] (dump_stack) from [<c002892c>] (warn_slowpath_common+0x84/0xb4) [<c002892c>] (warn_slowpath_common) from [<c00289f8>] (warn_slowpath_null+0x1c/0x24) [<c00289f8>] (warn_slowpath_null) from [<c0220290>] (kobject_get+0x64/0x70) [<c0220290>] (kobject_get) from [<c03e944c>] (cpufreq_cpu_get+0x88/0xc8) [<c03e944c>] (cpufreq_cpu_get) from [<c03e9500>] (cpufreq_get+0xc/0x64) [<c03e9500>] (cpufreq_get) from [<c0285288>] (actmon_thread_isr+0x134/0x198) [<c0285288>] (actmon_thread_isr) from [<c0069008>] (irq_thread_fn+0x1c/0x40) [<c0069008>] (irq_thread_fn) from [<c0069324>] (irq_thread+0x134/0x174) [<c0069324>] (irq_thread) from [<c0040290>] (kthread+0xdc/0xf4) [<c0040290>] (kthread) from [<c000f4b8>] (ret_from_fork+0x14/0x3c) ---[ end trace b7bd64a81b340c59 ]---

Cc: 3.18 stable@vger.kernel.org # 3.18 Signed-off-by: Tomeu Vizoso tomeu.vizoso@collabora.com Acked-by: Viresh Kumar viresh.kumar@linaro.org Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com --- 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 4473eba1d6b0..ae27ea61799a 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 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 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)