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Commit 83b0302d authored by Ashay Jaiswal's avatar Ashay Jaiswal Committed by Mark Brown
Browse files

regulator: core: fix race condition in regulator_put() 



The regulator framework maintains a list of consumer regulators
for a regulator device and protects it from concurrent access using
the regulator device's mutex lock.

In the case of regulator_put() the consumer is removed and regulator
device's parameters are updated without holding the regulator device's
mutex. This would lead to a race condition between the regulator_put()
and any function which traverses the consumer list or modifies regulator
device's parameters.
Fix this race condition by holding the regulator device's mutex in case
of regulator_put.

Signed-off-by: default avatarAshay Jaiswal <ashayj@codeaurora.org>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
parent 97bf6af1

drivers/regulator/core.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -1488,7 +1488,7 @@ struct regulator *regulator_get_optional(struct device *dev, const char *id) 
}

}

EXPORT_SYMBOL_GPL(regulator_get_optional);

EXPORT_SYMBOL_GPL(regulator_get_optional);





/* Locks held by regulator_put() */

/* regulator_list_mutex lock held by regulator_put() */

static void _regulator_put(struct regulator *regulator)

static void _regulator_put(struct regulator *regulator)

{

{

	struct regulator_dev *rdev;

	struct regulator_dev *rdev;
@@ -1503,12 +1503,14 @@ static void _regulator_put(struct regulator *regulator) 
	/* remove any sysfs entries */

	/* remove any sysfs entries */

	if (regulator->dev)

	if (regulator->dev)

		sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);

		sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);

	mutex_lock(&rdev->mutex);

	kfree(regulator->supply_name);

	kfree(regulator->supply_name);

	list_del(&regulator->list);

	list_del(&regulator->list);

	kfree(regulator);

	kfree(regulator);





	rdev->open_count--;

	rdev->open_count--;

	rdev->exclusive = 0;

	rdev->exclusive = 0;

	mutex_unlock(&rdev->mutex);





	module_put(rdev->owner);

	module_put(rdev->owner);

}

}