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Subject[PATCH 3.15 55/66] cpufreq: unlock when failing cpufreq_update_policy()
Date
3.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Aaron Plattner <aplattner@nvidia.com>

commit fefa8ff810c5ab4c4206aed9d159c4d6fe8d4f1c upstream.

Commit bd0fa9bb455d introduced a failure path to cpufreq_update_policy() if
cpufreq_driver->get(cpu) returns NULL. However, it jumps to the 'no_policy'
label, which exits without unlocking any of the locks the function acquired
earlier. This causes later calls into cpufreq to hang.

Fix this by creating a new 'unlock' label and jumping to that instead.

Fixes: bd0fa9bb455d ("cpufreq: Return error if ->get() failed in cpufreq_update_policy()")
Link: https://devtalk.nvidia.com/default/topic/751903/kernel-3-15-and-nv-drivers-337-340-failed-to-initialize-the-nvidia-kernel-module-gtx-550-ti-/
Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/cpufreq/cpufreq.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2166,10 +2166,8 @@ int cpufreq_update_policy(unsigned int c
struct cpufreq_policy new_policy;
int ret;

- if (!policy) {
- ret = -ENODEV;
- goto no_policy;
- }
+ if (!policy)
+ return -ENODEV;

down_write(&policy->rwsem);

@@ -2188,7 +2186,7 @@ int cpufreq_update_policy(unsigned int c
new_policy.cur = cpufreq_driver->get(cpu);
if (WARN_ON(!new_policy.cur)) {
ret = -EIO;
- goto no_policy;
+ goto unlock;
}

if (!policy->cur) {
@@ -2203,10 +2201,10 @@ int cpufreq_update_policy(unsigned int c

ret = cpufreq_set_policy(policy, &new_policy);

+unlock:
up_write(&policy->rwsem);

cpufreq_cpu_put(policy);
-no_policy:
return ret;
}
EXPORT_SYMBOL(cpufreq_update_policy);



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