[PATCH 5.17 710/772] thermal: devfreq_cooling: use local ops instead of global ops

Greg Kroah-Hartman
2022-06-07T21:42:30Z

From: Kant Fan <kant@allwinnertech.com>

commit b947769b8f778db130aad834257fcaca25df2edc upstream.

Fix access illegal address problem in following condition:

There are multiple devfreq cooling devices in system, some of them has
EM model but others do not. Energy model ops such as state2power will
append to global devfreq_cooling_ops when the cooling device with
EM model is registered. It makes the cooling device without EM model
also use devfreq_cooling_ops after appending when registered later by
of_devfreq_cooling_register_power() or of_devfreq_cooling_register().

The 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: 5.13+ <stable@vger.kernel.org> # 5.13+
Signed-off-by: Kant Fan <kant@allwinnertech.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/thermal/devfreq_cooling.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)

--- a/drivers/thermal/devfreq_cooling.c
+++ b/drivers/thermal/devfreq_cooling.c
@@ -358,21 +358,28 @@ of_devfreq_cooling_register_power(struct
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
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 @@ free_table:
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_reg
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 t

kfree(dfc->freq_table);
kfree(dfc);
+ kfree(ops);
}
EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);