Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH 5/5] cpufreq, add BUG() messages in critical paths to aid debugging failures | Date | Sat, 08 Nov 2014 03:00:15 +0100 |
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On Wednesday, November 05, 2014 09:53:59 AM Prarit Bhargava wrote: > Add some additional debug to capture failures in the locking scheme for > cpufreq. Instead of just a NULL pointer, these warnings will capture failure > points if the locking scheme for cpufreq is broken. > > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Cc: linux-pm@vger.kernel.org > Signed-off-by: Prarit Bhargava <prarit@redhat.com> > --- > drivers/cpufreq/cpufreq_governor.c | 32 +++++++++++++++++++++++++++----- > 1 file changed, 27 insertions(+), 5 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c > index b1ee597..f158882 100644 > --- a/drivers/cpufreq/cpufreq_governor.c > +++ b/drivers/cpufreq/cpufreq_governor.c > @@ -161,9 +161,18 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu) > EXPORT_SYMBOL_GPL(dbs_check_cpu); > > static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data, > - unsigned int delay) > + unsigned int delay, > + struct cpufreq_policy *policy) > { > - struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); > + struct cpu_dbs_common_info *cdbs; > + > + if (!dbs_data->cdata) { > + pr_emerg("common_dbs_data is NULL for %s but initialized = %d", > + policy->governor->name, > + atomic_read(&policy->governor->initialized)); > + BUG();
Is it necessary to crash the kernel here?
> + } > + cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); > > mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay); > } > @@ -185,10 +194,11 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, > * those works are canceled during CPU_DOWN_PREPARE so they > * can't possibly run on any other CPU. > */ > - __gov_queue_work(raw_smp_processor_id(), dbs_data, delay); > + __gov_queue_work(raw_smp_processor_id(), dbs_data, delay, > + policy); > } else { > for_each_cpu(i, policy->cpus) > - __gov_queue_work(i, dbs_data, delay); > + __gov_queue_work(i, dbs_data, delay, policy); > } > > out_unlock: > @@ -258,7 +268,13 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy, > else > dbs_data = cdata->gdbs_data; > > - WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT)); > + if (!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT)) { > + pr_emerg("governor_data is NULL but governor %s is initialized = %d [governor_enabled = %d event = %u]\n", > + policy->governor->name, > + atomic_read(&policy->governor->initialized), > + policy->governor_enabled, event); > + BUG();
And here?
> + } > > switch (event) { > case CPUFREQ_GOV_POLICY_INIT: > @@ -329,6 +345,12 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy, > case CPUFREQ_GOV_POLICY_EXIT: > mutex_lock(&dbs_data->usage_count_mutex); > if (atomic_dec_and_test(&dbs_data->usage_count)) { > + if (atomic_read(&policy->governor->initialized) > 1) { > + pr_emerg("Removing governor %s but initialized = %d, dbs_data->usage_count = 0\n", > + policy->governor->name, > + atomic_read(&policy->governor->initialized)); > + BUG(); > + } > sysfs_remove_group(get_governor_parent_kobj(policy), > get_sysfs_attr(dbs_data)); > >
-- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.
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