linux-kernel - [PATCH] regulator: fix memory leak with repeated set_machine

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Message-Id: <a199f158291a47de1d2d87482855802e3ff29494.1604544068.git.mirq-linux@rere.qmqm.pl>
Date:   Thu, 05 Nov 2020 03:52:35 +0100
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        Ahmad Fatoum <a.fatoum@...gutronix.de>
Subject: [PATCH] regulator: fix memory leak with repeated
 set_machine_constraints()

Fixed commit introduced a possible second call to
set_machine_constraints() and that allocates memory for
rdev->constraints. Move the allocation to the caller so
it's easier to manage and done once.

Fixes: aea6cb99703e ("regulator: resolve supply after creating regulator")
Cc: stable@...r.kernel.org
Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
 drivers/regulator/core.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 8521f74ee75c..402a72a70eb1 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1290,7 +1290,6 @@ static int _regulator_do_enable(struct regulator_dev *rdev);
 /**
  * set_machine_constraints - sets regulator constraints
  * @rdev: regulator source
- * @constraints: constraints to apply
  *
  * Allows platform initialisation code to define and constrain
  * regulator circuits e.g. valid voltage/current ranges, etc.  NOTE:
@@ -1298,21 +1297,11 @@ static int _regulator_do_enable(struct regulator_dev *rdev);
  * regulator operations to proceed i.e. set_voltage, set_current_limit,
  * set_mode.
  */
-static int set_machine_constraints(struct regulator_dev *rdev,
-	const struct regulation_constraints *constraints)
+static int set_machine_constraints(struct regulator_dev *rdev)
 {
 	int ret = 0;
 	const struct regulator_ops *ops = rdev->desc->ops;
 
-	if (constraints)
-		rdev->constraints = kmemdup(constraints, sizeof(*constraints),
-					    GFP_KERNEL);
-	else
-		rdev->constraints = kzalloc(sizeof(*constraints),
-					    GFP_KERNEL);
-	if (!rdev->constraints)
-		return -ENOMEM;
-
 	ret = machine_constraints_voltage(rdev, rdev->constraints);
 	if (ret != 0)
 		return ret;
@@ -5121,7 +5110,6 @@ struct regulator_dev *
 regulator_register(const struct regulator_desc *regulator_desc,
 		   const struct regulator_config *cfg)
 {
-	const struct regulation_constraints *constraints = NULL;
 	const struct regulator_init_data *init_data;
 	struct regulator_config *config = NULL;
 	static atomic_t regulator_no = ATOMIC_INIT(-1);
@@ -5260,14 +5248,23 @@ regulator_register(const struct regulator_desc *regulator_desc,
 
 	/* set regulator constraints */
 	if (init_data)
-		constraints = &init_data->constraints;
+		rdev->constraints = kmemdup(&init_data->constraints,
+					    sizeof(*rdev->constraints),
+					    GFP_KERNEL);
+	else
+		rdev->constraints = kzalloc(sizeof(*rdev->constraints),
+					    GFP_KERNEL);
+	if (!rdev->constraints) {
+		ret = -ENOMEM;
+		goto wash;
+	}
 
 	if (init_data && init_data->supply_regulator)
 		rdev->supply_name = init_data->supply_regulator;
 	else if (regulator_desc->supply_name)
 		rdev->supply_name = regulator_desc->supply_name;
 
-	ret = set_machine_constraints(rdev, constraints);
+	ret = set_machine_constraints(rdev);
 	if (ret == -EPROBE_DEFER) {
 		/* Regulator might be in bypass mode and so needs its supply
 		 * to set the constraints */
@@ -5276,7 +5273,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
 		 * that is just being created */
 		ret = regulator_resolve_supply(rdev);
 		if (!ret)
-			ret = set_machine_constraints(rdev, constraints);
+			ret = set_machine_constraints(rdev);
 		else
 			rdev_dbg(rdev, "unable to resolve supply early: %pe\n",
 				 ERR_PTR(ret));
-- 
2.20.1