From a3cde9534ebdafe18a9bbab208df724c57e6c8e8 Mon Sep 17 00:00:00 2001
From: Wen Yang <wenyang@linux.alibaba.com>
Date: Sun, 1 Dec 2019 11:02:50 +0800
Subject: [PATCH] regulator: core: fix regulator_register() error paths to properly release rdev
Git-commit: a3cde9534ebdafe18a9bbab208df724c57e6c8e8
Patch-mainline: v5.5-rc3
References: git-fixes

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/regulator/core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index c80f3fd9532d..2c3a03cfd381 100644
--- 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 @@ regulator_register(const struct regulator_desc *regulator_desc,
 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)
-- 
2.16.4