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Commit 98586ed8 authored by steven finney's avatar steven finney Committed by Dave Jones
Browse files

[CPUFREQ] Fix memory leak in cpufreq_stat 



When a CPU is taken offline in an SMP system, cpufreq_remove_dev()
nulls out the per-cpu policy before cpufreq_stats_free_table() can
make use of it.  cpufreq_stats_free_table() then skips the
call to sysfs_remove_group(), leaving about 100 bytes of sysfs-related
memory unclaimed each time a CPU-removal occurs. Break up
cpu_stats_free_table into sysfs and table portions, and
call the sysfs portion early.

Signed-off-by: default avatarSteven Finney <steven.finney@palm.com>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
Cc: stable@kernel.org
parent 335dc333

drivers/cpufreq/cpufreq_stats.c

+18 −3
Original line number Diff line number Diff line
@@ -165,17 +165,27 @@ static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq) 
	return -1;

}



/* should be called late in the CPU removal sequence so that the stats

 * memory is still available in case someone tries to use it.

 */

static void cpufreq_stats_free_table(unsigned int cpu)

{

	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);

	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);

	if (policy && policy->cpu == cpu)

		sysfs_remove_group(&policy->kobj, &stats_attr_group);

	if (stat) {

		kfree(stat->time_in_state);

		kfree(stat);

	}

	per_cpu(cpufreq_stats_table, cpu) = NULL;

}



/* must be called early in the CPU removal sequence (before

 * cpufreq_remove_dev) so that policy is still valid.

 */

static void cpufreq_stats_free_sysfs(unsigned int cpu)

{

	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);

	if (policy && policy->cpu == cpu)

		sysfs_remove_group(&policy->kobj, &stats_attr_group);

	if (policy)

		cpufreq_cpu_put(policy);

}
@@ -316,6 +326,9 @@ static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb, 
	case CPU_ONLINE_FROZEN:

		cpufreq_update_policy(cpu);

		break;

	case CPU_DOWN_PREPARE:

		cpufreq_stats_free_sysfs(cpu);

		break;

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		cpufreq_stats_free_table(cpu);
@@ -324,9 +337,11 @@ static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb, 
	return NOTIFY_OK;

}



/* priority=1 so this will get called before cpufreq_remove_dev */

static struct notifier_block cpufreq_stat_cpu_notifier __refdata =

{

	.notifier_call = cpufreq_stat_cpu_callback,

	.priority = 1,

};



static struct notifier_block notifier_policy_block = {