| From | Jiri Slaby <> | Subject | [PATCH 3.12 048/122] regulator: core: fix race condition in regulator_put() | Date | Tue, 17 Feb 2015 12:33:55 +0100 |
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From: Ashay Jaiswal <ashayj@codeaurora.org>
3.12-stable review patch. If anyone has any objections, please let me know.
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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: Jiri Slaby <jslaby@suse.cz> --- drivers/regulator/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index ea83084cb7d9..a2ce8e86ced7 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1474,7 +1474,7 @@ struct regulator *devm_regulator_get_optional(struct device *dev, } EXPORT_SYMBOL_GPL(devm_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; @@ -1489,12 +1489,14 @@ 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(®ulator->list); kfree(regulator); rdev->open_count--; rdev->exclusive = 0; + mutex_unlock(&rdev->mutex); module_put(rdev->owner); } -- 2.2.2
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