[PATCH 5.4 018/191] PM / devfreq: Dont fail devfreq_dev_release if not in list

From: Greg Kroah-Hartman
Date: Tue Jan 07 2020 - 15:57:51 EST

From: Leonard Crestez <leonard.crestez@xxxxxxx>

[ Upstream commit 42a6b25e67df6ee6675e8d1eaf18065bd73328ba ]

Right now devfreq_dev_release will print a warning and abort the rest of
the cleanup if the devfreq instance is not part of the global
devfreq_list. But this is a valid scenario, for example it can happen if
the governor can't be found or on any other init error that happens
after device_register.

Initialize devfreq->node to an empty list head in devfreq_add_device so
that list_del becomes a safe noop inside devfreq_dev_release and we can
continue the rest of the cleanup.

Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>
Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Reviewed-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/devfreq/devfreq.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index e185c8846916..ffd2d6b44dfb 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -588,11 +588,6 @@ static void devfreq_dev_release(struct device *dev)
struct devfreq *devfreq = to_devfreq(dev);

- if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
- mutex_unlock(&devfreq_list_lock);
- dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
- return;
- }

@@ -647,6 +642,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
devfreq->dev.parent = dev;
devfreq->dev.class = devfreq_class;
devfreq->dev.release = devfreq_dev_release;
+ INIT_LIST_HEAD(&devfreq->node);
devfreq->profile = profile;
strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
devfreq->previous_freq = profile->initial_freq;