[PATCH v2 05/33] HID: logitech-hidpp: do not store ERR_PTR in battery->ps

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

When power supply registration fails, storing the error pointer directly
in the battery supply field leaves it non-NULL. Callers such as the
connect handler and battery event handlers only check for non-NULL
before notifying the power supply core, causing an error-pointer
dereference oops and blocking retries on subsequent reconnect events.

Capture the registered power supply pointer in a local variable and
publish it to device state only after registration and sysfs linking
succeed.

Fixes: a52ec107fa81 ("HID: logitech-hidpp: create the battery for all types of HID++ devices")
Tested-by: Gideon Heinz <gideonheinz02@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/hid/hid-logitech-hidpp.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 0e1a9fd98faf..6ac41b7d76ee 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -4333,6 +4333,7 @@ static int hidpp_initialize_battery(struct hidpp_device *hidpp)
 	struct power_supply_desc *desc = &hidpp->battery.desc;
 	enum power_supply_property *battery_props;
 	struct hidpp_battery *battery;
+	struct power_supply *ps;
 	unsigned int num_battery_props;
 	unsigned long n;
 	int ret;
@@ -4413,15 +4414,16 @@ static int hidpp_initialize_battery(struct hidpp_device *hidpp)
 	desc->type = POWER_SUPPLY_TYPE_BATTERY;
 	desc->use_for_apm = 0;
 
-	battery->ps = devm_power_supply_register(&hidpp->hid_dev->dev,
-						 &battery->desc,
-						 &cfg);
-	if (IS_ERR(battery->ps))
-		return PTR_ERR(battery->ps);
+	ps = devm_power_supply_register(&hidpp->hid_dev->dev,
+					&battery->desc,
+					&cfg);
+	if (IS_ERR(ps))
+		return PTR_ERR(ps);
 
-	power_supply_powers(battery->ps, &hidpp->hid_dev->dev);
+	power_supply_powers(ps, &hidpp->hid_dev->dev);
+	battery->ps = ps;
 
-	return ret;
+	return 0;
 }
 
 /* Get name + serial for USB and Bluetooth HID++ devices */

-- 
2.56.0.542.g3ef89b7020-goog