From f6ec4fccbf9ac23feea3ae85470d9083c5a04663 Mon Sep 17 00:00:00 2001 From: Vincent Donnefort Date: Mon, 3 Sep 2018 09:02:07 +0900 Subject: [PATCH] PM / devfreq: stopping the governor before device_unregister() [ Upstream commit 2f061fd0c2d852e32e03a903fccd810663c5c31e ] 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 Reviewed-by: John Einar Reitan [cw00.choi: Fix merge conflict] Reviewed-by: Chanwoo Choi Signed-off-by: MyungJoo Ham Signed-off-by: Sasha Levin --- drivers/devfreq/devfreq.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 8e21bed..bcd2279 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -578,10 +578,6 @@ 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); @@ -717,7 +713,7 @@ 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) @@ -738,6 +734,9 @@ 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; -- 2.7.4