cpufreq: unlock when failing cpufreq_update_policy()

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>

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index abda6609d3e79f670c7143a01bbec53078e8bce1..558224cf55bfaa509bd9c5973e52cbfc01f3b453 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2166,10 +2166,8 @@ int cpufreq_update_policy(unsigned int cpu)
        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 cpu)
                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 cpu)
 
        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);