cpufreq: governor: Avoid accessing invalid governor_data
If cppc_cpufreq.ko is deleted at the same time that tuned-adm is
changing profiles, there is a small chance that a race can occur
between cpufreq_dbs_governor_exit() and cpufreq_dbs_governor_limits()
resulting in a system failure when the latter tries to use
policy->governor_data that has been freed by the former.
This patch uses gov_dbs_data_mutex to synchronize access.
Fixes: e788892ba3
(cpufreq: governor: Get rid of governor events)
Signed-off-by: Henry Willard <henry.willard@oracle.com>
[ rjw: Subject, minor white space adjustment ]
Cc: 4.8+ <stable@vger.kernel.org> # 4.8+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
parent
b018fc9800
commit
2a3eb51e30
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@ -555,12 +555,20 @@ EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_stop);
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void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy)
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{
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struct policy_dbs_info *policy_dbs = policy->governor_data;
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struct policy_dbs_info *policy_dbs;
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/* Protect gov->gdbs_data against cpufreq_dbs_governor_exit() */
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mutex_lock(&gov_dbs_data_mutex);
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policy_dbs = policy->governor_data;
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if (!policy_dbs)
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goto out;
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mutex_lock(&policy_dbs->update_mutex);
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cpufreq_policy_apply_limits(policy);
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gov_update_sample_delay(policy_dbs, 0);
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mutex_unlock(&policy_dbs->update_mutex);
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out:
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mutex_unlock(&gov_dbs_data_mutex);
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}
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EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_limits);
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