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PM / devfreq: stopping the governor before device_unregister() 

device_release() is freeing the resources before calling the device
specific release callback which is, in the case of devfreq, stopping
the governor.

It is a problem as some governors are using the device resources. e.g.
simpleondemand which is using the devfreq deferrable monitoring work. If it
is not stopped before the resources are freed, it might lead to a use after
free.

Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Reviewed-by: John Einar Reitan <john.reitan@arm.com>
[cw00.choi: Fix merge conflict]
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
This commit is contained in:
Vincent Donnefort 2018-09-03 09:02:07 +09:00 committed by MyungJoo Ham
parent f037eb8c1f
commit 2f061fd0c2
1 changed files with 4 additions and 5 deletions
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9
drivers/devfreq/devfreq.c
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@ -575,10 +575,6 @@ static void devfreq_dev_release(struct device *dev)
list_del(&devfreq->node);
mutex_unlock(&devfreq_list_lock);
if (devfreq->governor)
devfreq->governor->event_handler(devfreq,
DEVFREQ_GOV_STOP, NULL);
if (devfreq->profile->exit)
devfreq->profile->exit(devfreq->dev.parent);
@ -714,7 +710,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
err_init:
mutex_unlock(&devfreq_list_lock);
device_unregister(&devfreq->dev);
devfreq_remove_device(devfreq);
devfreq = NULL;
err_dev:
if (devfreq)
@ -735,6 +731,9 @@ int devfreq_remove_device(struct devfreq *devfreq)
if (!devfreq)
return -EINVAL;
if (devfreq->governor)
devfreq->governor->event_handler(devfreq,
DEVFREQ_GOV_STOP, NULL);
device_unregister(&devfreq->dev);
return 0;