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Commit 23969e24 authored by Jason Hrycay's avatar Jason Hrycay Committed by TARKZiM
Browse files

cpufreq_stats: Fix stats leak during update policy 



When the cpufreq policy is moved from one CPU to another, the percpu
stats_table is overwritten and leaked. Properly free the old stats table
and ensure its protected in the non-sysfs paths of update policy and
acct_update_power. The sysfs entries are removed in the cpufreq core
driver before migrating the policy. We introduce a new spinlock
specifically for these operations to avoid needed to convert all the
other spinlocks into the irq safe variants since acct_update_power is
typically called in ISR context.

[ported to apq8084-common by Corinna Vinschen <xda@vinschen.de>]

Change-Id: I95ff24c07834065cd0fd3c763a488a9843097a1d
Signed-off-by: default avatarJason Hrycay <jason.hrycay@motorola.com>
Reviewed-on: https://gerrit.mot.com/921752


SLTApproved: Slta Waiver <sltawvr@motorola.com>
SME-Granted: SME Approvals Granted
Reviewed-by: default avatarIgor Kovalenko <igork@motorola.com>
parent 9e19e7af

drivers/cpufreq/cpufreq_stats.c

+21 −3
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ DECLARE_HASHTABLE(uid_hash_table, UID_HASH_BITS); 


static spinlock_t cpufreq_stats_lock;



static DEFINE_SPINLOCK(cpufreq_stats_table_lock);

static DEFINE_SPINLOCK(task_time_in_state_lock); /* task->time_in_state */

static DEFINE_RT_MUTEX(uid_lock); /* uid_hash_table */
@@ -335,14 +336,16 @@ void acct_update_power(struct task_struct *task, cputime_t cputime) { 
	int cpu_freq_i;

	int all_freq_i;

	unsigned long flags;

	unsigned long stl_flags;



	if (!task)

		return;



	cpu_num = task_cpu(task);

	spin_lock_irqsave(&cpufreq_stats_table_lock, stl_flags);

	stats = per_cpu(cpufreq_stats_table, cpu_num);

	if (!stats)

		return;

		goto out;



	all_freq_i = atomic_read(&stats->all_freq_i);
@@ -363,15 +366,18 @@ void acct_update_power(struct task_struct *task, cputime_t cputime) { 


	powerstats = per_cpu(cpufreq_power_stats, cpu_num);

	if (!powerstats)

		return;

		goto out;



	cpu_freq_i = atomic_read(&stats->cpu_freq_i);

	if (cpu_freq_i == -1)

		return;

		goto out;



	curr = powerstats->curr[cpu_freq_i];

	if (task->cpu_power != ULLONG_MAX)

		task->cpu_power += curr * cputime_to_usecs(cputime);



out:

	spin_unlock_irqrestore(&cpufreq_stats_table_lock, stl_flags);

}

EXPORT_SYMBOL_GPL(acct_update_power);
@@ -643,7 +649,18 @@ error_alloc: 


static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)

{

	struct cpufreq_stats *old;

	struct cpufreq_stats *stat;

	unsigned long flags;



	spin_lock_irqsave(&cpufreq_stats_table_lock, flags);

	old = per_cpu(cpufreq_stats_table, policy->cpu);

	stat = per_cpu(cpufreq_stats_table, policy->last_cpu);



	if (old) {

		kfree(old->time_in_state);

		kfree(old);

	}



	pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",

		policy->cpu, policy->last_cpu);
@@ -658,6 +675,7 @@ static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy) 
			policy->last_cpu);

	per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;

	stat->cpu = policy->cpu;

	spin_unlock_irqrestore(&cpufreq_stats_table_lock, flags);

}



static void cpufreq_powerstats_create(unsigned int cpu,