Re: [PATCH] thermal: intel: powerclamp: Fix cpumask and max_idle module parameters

[srinivas pandruvada <srinivas.pandruvada@linux.intel.com>]

On Thu, 2023-03-30 at 09:42 -0400, David Arcari wrote:
Reviewed-by: Srinivas Pandruvada <>> When cpumask is specified as a module parameter the value is
> overwritten by the module init routine.  This can easily be fixed
> by checking to see if the mask has already been allocated in the
> init routine.
> 
> When max_idle is specified as a module parameter a panic will occur.
> The problem is that the idle_injection_cpu_mask is not allocated
> until
> the module init routine executes. This can easily be fixed by
> allocating
> the cpumask if it's not already allocated.
> 
> Fixes: ebf519710218 ("thermal: intel: powerclamp: Add two module
> parameters")
> 
> Signed-off-by: David Arcari <darcari@redhat.com>
Reviewed-by: Srinivas Pandruvada<srinivas.pandruvada@linux.intel.com>

> 
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Cc: Amit Kucheria <amitk@kernel.org>
> Cc: Zhang Rui <rui.zhang@intel.com>
> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> Cc: David Arcari <darcari@redhat.com>
> Cc: Chen Yu <yu.c.chen@intel.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: stable@vger.kernel.org
> 
> ---
>  drivers/thermal/intel/intel_powerclamp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/intel/intel_powerclamp.c
> b/drivers/thermal/intel/intel_powerclamp.c
> index c7ba5680cd48..91fc7e239497 100644
> --- a/drivers/thermal/intel/intel_powerclamp.c
> +++ b/drivers/thermal/intel/intel_powerclamp.c
> @@ -235,6 +235,12 @@ static int max_idle_set(const char *arg, const
> struct kernel_param *kp)
>                 goto skip_limit_set;
>         }
>  
> +       if (!cpumask_available(idle_injection_cpu_mask)) {
> +               ret =
> allocate_copy_idle_injection_mask(cpu_present_mask);
> +               if (ret)
> +                       goto skip_limit_set;
> +       }
> +
>         if (check_invalid(idle_injection_cpu_mask, new_max_idle)) {
>                 ret = -EINVAL;
>                 goto skip_limit_set;
> @@ -791,7 +797,8 @@ static int __init powerclamp_init(void)
>                 return retval;
>  
>         mutex_lock(&powerclamp_lock);
> -       retval = allocate_copy_idle_injection_mask(cpu_present_mask);
> +       if (!cpumask_available(idle_injection_cpu_mask))
> +               retval =
> allocate_copy_idle_injection_mask(cpu_present_mask);
>         mutex_unlock(&powerclamp_lock);
>  
>         if (retval)