[RFC PATCH 12/19] cpufreq: fix locking of policy->rwsem in cpufreq_init_policy

[Juri Lelli]

There are paths in cpufreq_init_policy where policy is used, but its rwsem
is not held.

Fix it.

Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Juri Lelli <juri.lelli@xxxxxxx>
---
 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