[PATCH V2 1/1] cpufreq: fix NULL pointer deference atod_set_powersave_bias()

From: Jacob Shin
Date: Thu Jun 27 2013 - 10:39:48 EST


When initializing the default powersave_bias value, we need to first
make sure that this policy is running the ondemand governor.

Reported-by: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>
Signed-off-by: Jacob Shin <jacob.shin@xxxxxxx>
---
drivers/cpufreq/cpufreq_governor.c | 1 +
drivers/cpufreq/cpufreq_ondemand.c | 17 +++++++++++++----
2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index dc9b72e..834ad86 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -403,6 +403,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
gov_cancel_work(dbs_data, policy);

mutex_lock(&dbs_data->mutex);
+ cpu_cdbs->cur_policy = NULL;
mutex_destroy(&cpu_cdbs->timer_mutex);

mutex_unlock(&dbs_data->mutex);
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 4b9bb5d..93eb5cb 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -47,6 +47,8 @@ static struct od_ops od_ops;
static struct cpufreq_governor cpufreq_gov_ondemand;
#endif

+static unsigned int default_powersave_bias;
+
static void ondemand_powersave_bias_init_cpu(int cpu)
{
struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
@@ -543,7 +545,7 @@ static int od_init(struct dbs_data *dbs_data)

tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
tuners->ignore_nice = 0;
- tuners->powersave_bias = 0;
+ tuners->powersave_bias = default_powersave_bias;
tuners->io_is_busy = should_io_be_busy();

dbs_data->tuners = tuners;
@@ -585,6 +587,7 @@ static void od_set_powersave_bias(unsigned int powersave_bias)
unsigned int cpu;
cpumask_t done;

+ default_powersave_bias = powersave_bias;
cpumask_clear(&done);

get_online_cpus();
@@ -593,11 +596,17 @@ static void od_set_powersave_bias(unsigned int powersave_bias)
continue;

policy = per_cpu(od_cpu_dbs_info, cpu).cdbs.cur_policy;
- dbs_data = policy->governor_data;
- od_tuners = dbs_data->tuners;
- od_tuners->powersave_bias = powersave_bias;
+ if (!policy)
+ continue;

cpumask_or(&done, &done, policy->cpus);
+
+ if (policy->governor != &cpufreq_gov_ondemand)
+ continue;
+
+ dbs_data = policy->governor_data;
+ od_tuners = dbs_data->tuners;
+ od_tuners->powersave_bias = default_powersave_bias;
}
put_online_cpus();
}
--
1.7.10.4


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