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Subject[RFC PATCH 12/19] cpufreq: fix locking of policy->rwsem in cpufreq_init_policy
Date
There are paths in cpufreq_init_policy where policy is used, but its rwsem
is not held.

Fix it.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
---
drivers/cpufreq/cpufreq.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index e7fc5c9..2c7cc6c73 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -998,21 +998,24 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cp
{
int ret = 0;

+ down_write(&policy->rwsem);
+
/* Has this CPU been taken care of already? */
- if (cpumask_test_cpu(cpu, policy->cpus))
+ if (cpumask_test_cpu(cpu, policy->cpus)) {
+ up_write(&policy->rwsem);
return 0;
+ }

if (has_target()) {
ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
if (ret) {
+ up_write(&policy->rwsem);
pr_err("%s: Failed to stop governor\n", __func__);
return ret;
}
}

- down_write(&policy->rwsem);
cpumask_set_cpu(cpu, policy->cpus);
- up_write(&policy->rwsem);

if (has_target()) {
ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
@@ -1020,10 +1023,12 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cp
ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);

if (ret) {
+ up_write(&policy->rwsem);
pr_err("%s: Failed to start governor\n", __func__);
return ret;
}
}
+ up_write(&policy->rwsem);

return 0;
}
--
2.2.2
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