| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 43/57] regulator: core: fix race condition in regulator_put() | Date | Tue, 3 Feb 2015 15:14:34 -0800 |
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3.18-stable review patch. If anyone has any objections, please let me know.
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From: Ashay Jaiswal <ashayj@codeaurora.org>
commit 83b0302d347a49f951e904184afe57ac3723476e upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/regulator/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1488,7 +1488,7 @@ struct regulator *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) { struct regulator_dev *rdev; @@ -1503,12 +1503,14 @@ static void _regulator_put(struct regula /* 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(®ulator->list); kfree(regulator); rdev->open_count--; rdev->exclusive = 0; + mutex_unlock(&rdev->mutex); module_put(rdev->owner); }
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