regulator: core: fix regulator_register() error paths to properly release rdev

There are several issues with the error handling code of
the regulator_register() function:
        ret = device_register(&rdev->dev);
        if (ret != 0) {
                put_device(&rdev->dev); --> rdev released
                goto unset_supplies;
        }
...
unset_supplies:
...
        unset_regulator_supplies(rdev); --> use-after-free
...
clean:
        if (dangling_of_gpiod)
                gpiod_put(config->ena_gpiod);
        kfree(rdev);                     --> double free

We add a variable to record the failure of device_register() and
move put_device() down a bit to avoid the above issues.

Fixes: c438b9d01736 ("regulator: core: Move registration of regulator device")
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/20191201030250.38074-1-wenyang@linux.alibaba.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index c80f3fd9532ddf7d16b5246ca27731f9c7863e17..2c3a03cfd381dcd2d807b943ad033014ded0b20b 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -4998,6 +4998,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
        struct regulator_dev *rdev;
        bool dangling_cfg_gpiod = false;
        bool dangling_of_gpiod = false;
+       bool reg_device_fail = false;
        struct device *dev;
        int ret, i;
 
@@ -5183,7 +5184,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
        dev_set_drvdata(&rdev->dev, rdev);
        ret = device_register(&rdev->dev);
        if (ret != 0) {
-               put_device(&rdev->dev);
+               reg_device_fail = true;
                goto unset_supplies;
        }
 
@@ -5213,7 +5214,10 @@ wash:
 clean:
        if (dangling_of_gpiod)
                gpiod_put(config->ena_gpiod);
-       kfree(rdev);
+       if (reg_device_fail)
+               put_device(&rdev->dev);
+       else
+               kfree(rdev);
        kfree(config);
 rinse:
        if (dangling_cfg_gpiod)