On Mon, 2018-03-19 at 19:06 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: "Rafael J. Wysocki" <rafael.j.wyso...@intel.com>
> 
> 
> [ Upstream commit a8b149d32b663c1a4105273295184b78f53d33cf ]
[...]
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -551,6 +551,8 @@ static int cpufreq_parse_governor(char *
>                       *governor = t;
>                       err = 0;
>               }
> +             if (t && !try_module_get(t->owner))
> +                     t = NULL;

This won't work because t is dead after this point.  The fix appears to
depend on:

commit 045149e6a22119e5bf0d16a0b24a4173a2abb71d
Author: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Date:   Thu Nov 23 01:23:16 2017 +0100

    cpufreq: Clean up cpufreq_parse_governor()

which moves the assignment to *governor further down.

Ben.
 
>               mutex_unlock(&cpufreq_governor_mutex);
>       }
> @@ -669,6 +671,10 @@ static ssize_t store_scaling_governor(st
>               return -EINVAL;
>  
>       ret = cpufreq_set_policy(policy, &new_policy);
> +
> +     if (new_policy.governor)
> +             module_put(new_policy.governor->owner);
> +
>       return ret ? ret : count;
>  }
>  

-- 
Ben Hutchings
Software Developer, Codethink Ltd.

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