[PATCH AUTOSEL 5.4 003/187] regulator: fix use after free issue

Sasha Levin
2019-12-27T17:41:04Z

From: Wen Yang <wenyang@linux.alibaba.com>

[ Upstream commit 4affd79a125ac91e6a53be843ea3960a8fc00cbb ]

This is caused by dereferencing 'rdev' after put_device() in
the _regulator_get()/_regulator_put() functions.
This patch just moves the put_device() down a bit to avoid the
issue.

Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20191124145835.25999-1-wenyang@linux.alibaba.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/regulator/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index a46be221dbdc..71c1467e1e2e 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1935,8 +1935,8 @@ struct regulator *_regulator_get(struct device *dev, const char *id,
regulator = create_regulator(rdev, dev, id);
if (regulator == NULL) {
regulator = ERR_PTR(-ENOMEM);
- put_device(&rdev->dev);
module_put(rdev->owner);
+ put_device(&rdev->dev);
return regulator;
}

@@ -2057,13 +2057,13 @@ static void _regulator_put(struct regulator *regulator)

rdev->open_count--;
rdev->exclusive = 0;
- put_device(&rdev->dev);
regulator_unlock(rdev);

kfree_const(regulator->supply_name);
kfree(regulator);

module_put(rdev->owner);
+ put_device(&rdev->dev);
}

/**
--
2.20.1