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regulator: core: fix race condition in regulator_put()

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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: Ashay Jaiswal <ashayj@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
This commit is contained in:
Ashay Jaiswal 2015-01-08 18:54:25 +05:30 committed by Mark Brown
parent 97bf6af1f9
commit 83b0302d34
1 changed files with 3 additions and 1 deletions
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4
drivers/regulator/core.c
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@ -1488,7 +1488,7 @@ struct regulator *regulator_get_optional(struct device *dev, const char *id)
}
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)
{
struct regulator_dev *rdev;
@ -1503,12 +1503,14 @@ static void _regulator_put(struct regulator *regulator)
/* remove any sysfs entries */
if (regulator->dev)
sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);
mutex_lock(&rdev->mutex);
kfree(regulator->supply_name);
list_del(&regulator->list);
kfree(regulator);
rdev->open_count--;
rdev->exclusive = 0;
mutex_unlock(&rdev->mutex);
module_put(rdev->owner);
}