lkml.org 
[lkml]   [2016]   [Jan]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH 13/19] cpufreq: fix locking of policy->rwsem in cpufreq_offline_prepare
Date
There are paths in cpufreq_offline_prepare 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 | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 2c7cc6c73..91158b0 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1332,13 +1332,13 @@ static void cpufreq_offline_prepare(unsigned int cpu)
return;
}

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

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

if (policy_is_inactive(policy)) {
@@ -1356,12 +1356,16 @@ static void cpufreq_offline_prepare(unsigned int cpu)
/* Start governor again for active policy */
if (!policy_is_inactive(policy)) {
if (has_target()) {
- int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ int ret;
+
+ down_write(&policy->rwsem);
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
if (!ret)
ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);

if (ret)
pr_err("%s: Failed to start governor\n", __func__);
+ up_write(&policy->rwsem);
}
} else if (cpufreq_driver->stop_cpu) {
cpufreq_driver->stop_cpu(policy);
--
2.2.2
\
 
 \ /
  Last update: 2016-01-11 19:21    [W:0.268 / U:0.176 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site