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SubjectRe: [PATCH v2] thermal: devfreq_cooling: use local ops instead of global ops
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Hi Kant,

On 3/25/22 07:30, Kant Fan wrote:
> Fix access illegal address problem in following condition:
> There are muti devfreq cooling devices in system, some of them has
> em model but other does not, energy model ops such as state2power will
> append to global devfreq_cooling_ops when the cooling device with
> em model register. It makes the cooling device without em model
> also use devfreq_cooling_ops after appending when register later by
> of_devfreq_cooling_register_power() or of_devfreq_cooling_register().
>
> IPA governor regards the cooling devices without em model as a power actor
> because they also have energy model ops, and will access illegal address
> at dfc->em_pd when execute cdev->ops->get_requested_power,
> cdev->ops->state2power or cdev->ops->power2state.
>
> Fixes: 615510fe13bd2 ("thermal: devfreq_cooling: remove old power model and use EM")
> Cc: stable@vger.kernel.org # 5.13+
> Signed-off-by: Kant Fan <kant@allwinnertech.com>
> ---
> drivers/thermal/devfreq_cooling.c | 25 ++++++++++++++++++-------
> 1 file changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
> index 4310cb342a9f..d38a80adec73 100644
> --- a/drivers/thermal/devfreq_cooling.c
> +++ b/drivers/thermal/devfreq_cooling.c
> @@ -358,21 +358,28 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
> struct thermal_cooling_device *cdev;
> struct device *dev = df->dev.parent;
> struct devfreq_cooling_device *dfc;
> + struct thermal_cooling_device_ops *ops;
> char *name;
> int err, num_opps;
>
> - dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
> - if (!dfc)
> + ops = kmemdup(&devfreq_cooling_ops, sizeof(*ops), GFP_KERNEL);
> + if (!ops)
> return ERR_PTR(-ENOMEM);
>
> + dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
> + if (!dfc) {
> + err = -ENOMEM;
> + goto free_ops;
> + }
> +
> dfc->devfreq = df;
>
> dfc->em_pd = em_pd_get(dev);
> if (dfc->em_pd) {
> - devfreq_cooling_ops.get_requested_power =
> + ops->get_requested_power =
> devfreq_cooling_get_requested_power;
> - devfreq_cooling_ops.state2power = devfreq_cooling_state2power;
> - devfreq_cooling_ops.power2state = devfreq_cooling_power2state;
> + ops->state2power = devfreq_cooling_state2power;
> + ops->power2state = devfreq_cooling_power2state;
>
> dfc->power_ops = dfc_power;
>
> @@ -407,8 +414,7 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
> if (!name)
> goto remove_qos_req;
>
> - cdev = thermal_of_cooling_device_register(np, name, dfc,
> - &devfreq_cooling_ops);
> + cdev = thermal_of_cooling_device_register(np, name, dfc, ops);
> kfree(name);
>
> if (IS_ERR(cdev)) {
> @@ -429,6 +435,8 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
> kfree(dfc->freq_table);
> free_dfc:
> kfree(dfc);
> +free_ops:
> + kfree(ops);
>
> return ERR_PTR(err);
> }
> @@ -510,11 +518,13 @@ EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);
> void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
> {
> struct devfreq_cooling_device *dfc;
> + const struct thermal_cooling_device_ops *ops;
> struct device *dev;
>
> if (IS_ERR_OR_NULL(cdev))
> return;
>
> + ops = cdev->ops;
> dfc = cdev->devdata;
> dev = dfc->devfreq->dev.parent;
>
> @@ -525,5 +535,6 @@ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
>
> kfree(dfc->freq_table);
> kfree(dfc);
> + kfree(ops);
> }
> EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);


Thank you for updating it, LGTM

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>

Regards,
Lukasz

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