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cpufreq / stats: fix race between stats allocation and first usage

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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: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Konstantin Khlebnikov 2012-12-15 00:22:02 +01:00 committed by Rafael J. Wysocki
parent d1c3ed669a
commit 56836fb4da
1 changed files with 7 additions and 4 deletions
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11
drivers/cpufreq/cpufreq_stats.c
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@ -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)