| From | Ben Hutchings <> | Date | Tue, 17 Feb 2015 01:46:53 +0000 | Subject | [PATCH 3.2 092/152] regulator: core: fix race condition in regulator_put() |
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3.2.67-rc1 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> [bwh: Backported to 3.2: - Adjust context - Don't touch the comment; __regulator_put() has not been split out of regulator_put() here] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/regulator/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1314,12 +1314,14 @@ void regulator_put(struct regulator *reg device_remove_file(regulator->dev, ®ulator->dev_attr); kfree(regulator->dev_attr.attr.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); mutex_unlock(®ulator_list_mutex);
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