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Subject[PATCH 2/2] power: supply: max14656: fix potential use-after-free
Date
Explicitly cancel/sync the irq_work delayed work, otherwise
there's a chance that it will run after the device is removed,
which would result in a use-after-free.

Note that cancel/sync should happen:
- after irq's have been disabled, as the isr re-schedules the work
- before the power supply is unregistered, because the work func
uses the power supply handle.

Cc: Alexander Kurz <akurz@blala.de>
Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
---
.../power/supply/max14656_charger_detector.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/max14656_charger_detector.c b/drivers/power/supply/max14656_charger_detector.c
index d19307f791c6..9e6472834e37 100644
--- a/drivers/power/supply/max14656_charger_detector.c
+++ b/drivers/power/supply/max14656_charger_detector.c
@@ -240,6 +240,14 @@ static enum power_supply_property max14656_battery_props[] = {
POWER_SUPPLY_PROP_MANUFACTURER,
};

+static void stop_irq_work(void *data)
+{
+ struct max14656_chip *chip = data;
+
+ cancel_delayed_work_sync(&chip->irq_work);
+}
+
+
static int max14656_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -278,8 +286,6 @@ static int max14656_probe(struct i2c_client *client,
if (ret)
return -ENODEV;

- INIT_DELAYED_WORK(&chip->irq_work, max14656_irq_worker);
-
chip->detect_psy = devm_power_supply_register(dev,
&chip->psy_desc, &psy_cfg);
if (IS_ERR(chip->detect_psy)) {
@@ -287,6 +293,13 @@ static int max14656_probe(struct i2c_client *client,
return -EINVAL;
}

+ INIT_DELAYED_WORK(&chip->irq_work, max14656_irq_worker);
+ ret = devm_add_action(dev, stop_irq_work, chip);
+ if (ret) {
+ dev_err(dev, "devm_add_action %d failed\n", ret);
+ return ret;
+ }
+
ret = devm_request_irq(dev, chip->irq, max14656_irq,
IRQF_TRIGGER_FALLING,
MAX14656_NAME, chip);
--
2.17.1
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