cpufreq: fix NULL pointer deference at od_set_powersave_bias()

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

Reported-and-tested-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 4b9bb5def6f159a126e4f05aa6a76d365c6a23f8..93eb5cbcc1f639bf1ec52479a169a49deecd72f5 100644 (file)
--- 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();
 }