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Commit 56836fb4 authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Rafael J. Wysocki
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cpufreq / stats: fix race between stats allocation and first usage 



This patch forces complete struct cpufreq_stats allocation for all cpus before
registering CPUFREQ_TRANSITION_NOTIFIER notifier, otherwise in some conditions
cpufreq_stat_notifier_trans() can be called in the middle of stats allocation,
in this case cpufreq_stats_table already exists, but stat->freq_table is NULL.

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent d1c3ed66

drivers/cpufreq/cpufreq_stats.c

+7 −4
Original line number Diff line number Diff line
@@ -364,18 +364,21 @@ static int __init cpufreq_stats_init(void) 
	if (ret)

		return ret;



	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);

	for_each_online_cpu(cpu)

		cpufreq_update_policy(cpu);



	ret = cpufreq_register_notifier(&notifier_trans_block,

				CPUFREQ_TRANSITION_NOTIFIER);

	if (ret) {

		cpufreq_unregister_notifier(&notifier_policy_block,

				CPUFREQ_POLICY_NOTIFIER);

		unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);

		for_each_online_cpu(cpu)

			cpufreq_stats_free_table(cpu);

		return ret;

	}



	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);

	for_each_online_cpu(cpu) {

		cpufreq_update_policy(cpu);

	}

	return 0;

}

static void __exit cpufreq_stats_exit(void)