Hi Viresh, On Thu, Jun 02, 2016 at 07:34:56PM +0530, Viresh Kumar wrote: > Most of the callers of cpufreq_frequency_get_table() already have the > pointer to a valid 'policy' structure and they don't really need to go > through the per-cpu variable first and then a check to validate the > frequency, in order to find the freq-table for the policy. > > Directly use the policy->freq_table field instead for them. > > Only one user of that API is left after above changes, cpu_cooling.c and > it accesses the freq_table in a racy way as the policy can get freed in > between. > > Fix it by using cpufreq_cpu_get() properly.
In 5a31d594a973 ("cpufreq: Allow freq_table to be obtained for offline CPUs") you did the opposite: don't use cpufreq_cpu_get_raw() because it won't give you the policy of a cpu that is offline. Now you are arguing that we should go back to cpufreq_cpu_get() which implicitly calls cpufreq_cpu_get_raw(). Won't we hit the same issue that 5a31d594a973 was trying to prevent: that we can't get a freq_table for a cpu that is offline? Cheers, Javi > Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org> > --- > drivers/cpufreq/cpufreq.c | 38 > +++++++++++++---------------------- > drivers/cpufreq/cpufreq_ondemand.c | 2 +- > drivers/cpufreq/cpufreq_stats.c | 3 +-- > drivers/cpufreq/freq_table.c | 9 +++------ > drivers/cpufreq/ppc_cbe_cpufreq_pmi.c | 3 +-- > drivers/thermal/cpu_cooling.c | 22 +++++++++++++++----- > include/linux/cpufreq.h | 2 -- > 7 files changed, 37 insertions(+), 42 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index fbc97b1fa371..1833eda1f9d4 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -126,15 +126,6 @@ struct kobject *get_governor_parent_kobj(struct > cpufreq_policy *policy) > } > EXPORT_SYMBOL_GPL(get_governor_parent_kobj); > > -struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu) > -{ > - struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); > - > - return policy && !policy_is_inactive(policy) ? > - policy->freq_table : NULL; > -} > -EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table); > - > static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) > { > u64 idle_time; > @@ -1950,7 +1941,7 @@ int __cpufreq_driver_target(struct cpufreq_policy > *policy, > if (!cpufreq_driver->target_index) > return -EINVAL; > > - freq_table = cpufreq_frequency_get_table(policy->cpu); > + freq_table = policy->freq_table; > if (unlikely(!freq_table)) { > pr_err("%s: Unable to find freq_table\n", __func__); > return -EINVAL; > @@ -2345,26 +2336,25 @@ static struct notifier_block __refdata > cpufreq_cpu_notifier = { > *********************************************************************/ > static int cpufreq_boost_set_sw(int state) > { > - struct cpufreq_frequency_table *freq_table; > struct cpufreq_policy *policy; > int ret = -EINVAL; > > for_each_active_policy(policy) { > - freq_table = cpufreq_frequency_get_table(policy->cpu); > - if (freq_table) { > - ret = cpufreq_frequency_table_cpuinfo(policy, > - freq_table); > - if (ret) { > - pr_err("%s: Policy frequency update failed\n", > - __func__); > - break; > - } > + if (!policy->freq_table) > + continue; > > - down_write(&policy->rwsem); > - policy->user_policy.max = policy->max; > - cpufreq_governor_limits(policy); > - up_write(&policy->rwsem); > + ret = cpufreq_frequency_table_cpuinfo(policy, > + policy->freq_table); > + if (ret) { > + pr_err("%s: Policy frequency update failed\n", > + __func__); > + break; > } > + > + down_write(&policy->rwsem); > + policy->user_policy.max = policy->max; > + cpufreq_governor_limits(policy); > + up_write(&policy->rwsem); > } > > return ret; > diff --git a/drivers/cpufreq/cpufreq_ondemand.c > b/drivers/cpufreq/cpufreq_ondemand.c > index c84fc2240d49..4d2fe2710c5d 100644 > --- a/drivers/cpufreq/cpufreq_ondemand.c > +++ b/drivers/cpufreq/cpufreq_ondemand.c > @@ -113,7 +113,7 @@ static void ondemand_powersave_bias_init(struct > cpufreq_policy *policy) > { > struct od_policy_dbs_info *dbs_info = > to_dbs_info(policy->governor_data); > > - dbs_info->freq_table = cpufreq_frequency_get_table(policy->cpu); > + dbs_info->freq_table = policy->freq_table; > dbs_info->freq_lo = 0; > } > > diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c > index c6e7f81a0397..06d3abdffd3a 100644 > --- a/drivers/cpufreq/cpufreq_stats.c > +++ b/drivers/cpufreq/cpufreq_stats.c > @@ -157,11 +157,10 @@ void cpufreq_stats_create_table(struct cpufreq_policy > *policy) > unsigned int i = 0, count = 0, ret = -ENOMEM; > struct cpufreq_stats *stats; > unsigned int alloc_size; > - unsigned int cpu = policy->cpu; > struct cpufreq_frequency_table *pos, *table; > > /* We need cpufreq table for creating stats table */ > - table = cpufreq_frequency_get_table(cpu); > + table = policy->freq_table; > if (unlikely(!table)) > return; > > diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c > index 4e5c5dbfed7a..f52b5473b1f4 100644 > --- a/drivers/cpufreq/freq_table.c > +++ b/drivers/cpufreq/freq_table.c > @@ -106,12 +106,10 @@ EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify); > */ > int cpufreq_generic_frequency_table_verify(struct cpufreq_policy *policy) > { > - struct cpufreq_frequency_table *table = > - cpufreq_frequency_get_table(policy->cpu); > - if (!table) > + if (!policy->freq_table) > return -ENODEV; > > - return cpufreq_frequency_table_verify(policy, table); > + return cpufreq_frequency_table_verify(policy, policy->freq_table); > } > EXPORT_SYMBOL_GPL(cpufreq_generic_frequency_table_verify); > > @@ -210,9 +208,8 @@ EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target); > int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy, > unsigned int freq) > { > - struct cpufreq_frequency_table *pos, *table; > + struct cpufreq_frequency_table *pos, *table = policy->freq_table; > > - table = cpufreq_frequency_get_table(policy->cpu); > if (unlikely(!table)) { > pr_debug("%s: Unable to find frequency table\n", __func__); > return -ENOENT; > diff --git a/drivers/cpufreq/ppc_cbe_cpufreq_pmi.c > b/drivers/cpufreq/ppc_cbe_cpufreq_pmi.c > index 7c4cd5c634f2..dc112481a408 100644 > --- a/drivers/cpufreq/ppc_cbe_cpufreq_pmi.c > +++ b/drivers/cpufreq/ppc_cbe_cpufreq_pmi.c > @@ -94,7 +94,7 @@ static int pmi_notifier(struct notifier_block *nb, > unsigned long event, void *data) > { > struct cpufreq_policy *policy = data; > - struct cpufreq_frequency_table *cbe_freqs; > + struct cpufreq_frequency_table *cbe_freqs = policy->freq_table; > u8 node; > > /* Should this really be called for CPUFREQ_ADJUST and CPUFREQ_NOTIFY > @@ -103,7 +103,6 @@ static int pmi_notifier(struct notifier_block *nb, > if (event == CPUFREQ_START) > return 0; > > - cbe_freqs = cpufreq_frequency_get_table(policy->cpu); > node = cbe_cpu_to_node(policy->cpu); > > pr_debug("got notified, event=%lu, node=%u\n", event, node); > diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c > index 6ceac4f2d4b2..63f760869651 100644 > --- a/drivers/thermal/cpu_cooling.c > +++ b/drivers/thermal/cpu_cooling.c > @@ -787,6 +787,7 @@ __cpufreq_cooling_register(struct device_node *np, > const struct cpumask *clip_cpus, u32 capacitance, > get_static_t plat_static_func) > { > + struct cpufreq_policy *policy; > struct thermal_cooling_device *cool_dev; > struct cpufreq_cooling_device *cpufreq_dev; > char dev_name[THERMAL_NAME_LENGTH]; > @@ -794,15 +795,24 @@ __cpufreq_cooling_register(struct device_node *np, > unsigned int freq, i, num_cpus; > int ret; > > - table = cpufreq_frequency_get_table(cpumask_first(clip_cpus)); > + policy = cpufreq_cpu_get(cpumask_first(clip_cpus)); > + if (!policy) { > + pr_debug("%s: CPUFreq policy not found\n", __func__); > + return ERR_PTR(-EPROBE_DEFER); > + } > + > + table = policy->freq_table; > if (!table) { > pr_debug("%s: CPUFreq table not found\n", __func__); > - return ERR_PTR(-EPROBE_DEFER); > + cool_dev = ERR_PTR(-ENODEV); > + goto put_policy; > } > > cpufreq_dev = kzalloc(sizeof(*cpufreq_dev), GFP_KERNEL); > - if (!cpufreq_dev) > - return ERR_PTR(-ENOMEM); > + if (!cpufreq_dev) { > + cool_dev = ERR_PTR(-ENOMEM); > + goto put_policy; > + } > > num_cpus = cpumask_weight(clip_cpus); > cpufreq_dev->time_in_idle = kcalloc(num_cpus, > @@ -892,7 +902,7 @@ __cpufreq_cooling_register(struct device_node *np, > CPUFREQ_POLICY_NOTIFIER); > mutex_unlock(&cooling_cpufreq_lock); > > - return cool_dev; > + goto put_policy; > > remove_idr: > release_idr(&cpufreq_idr, cpufreq_dev->id); > @@ -906,6 +916,8 @@ __cpufreq_cooling_register(struct device_node *np, > kfree(cpufreq_dev->time_in_idle); > free_cdev: > kfree(cpufreq_dev); > +put_policy: > + cpufreq_cpu_put(policy); > > return cool_dev; > } > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > index 7ed93c310c08..1342cbc0f25e 100644 > --- a/include/linux/cpufreq.h > +++ b/include/linux/cpufreq.h > @@ -632,8 +632,6 @@ static inline bool policy_has_boost_freq(struct > cpufreq_policy *policy) > return false; > } > #endif > -/* the following funtion is for cpufreq core use only */ > -struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int > cpu); > > /* the following are really really optional */ > extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs; > -- > 2.7.1.410.g6faf27b >