From: Hans de Goede Date: Sat, 15 Apr 2023 16:07:31 +0000 (+0200) Subject: power: supply: bq25890: Fix external_power_changed race X-Git-Tag: baikal/aarch64/sdk6.2~95 X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=12bc447f9d040a664413942560a5f00e767395d0;p=kernel.git power: supply: bq25890: Fix external_power_changed race commit 029a443b9b6424170f00f6dd5b7682e682cce92e upstream. bq25890_charger_external_power_changed() dereferences bq->charger, which gets sets in bq25890_power_supply_init() like this: bq->charger = devm_power_supply_register(bq->dev, &bq->desc, &psy_cfg); As soon as devm_power_supply_register() has called device_add() the external_power_changed callback can get called. So there is a window where bq25890_charger_external_power_changed() may get called while bq->charger has not been set yet leading to a NULL pointer dereference. This race hits during boot sometimes on a Lenovo Yoga Book 1 yb1-x90f when the cht_wcove_pwrsrc (extcon) power_supply is done with detecting the connected charger-type which happens to exactly hit the small window: BUG: kernel NULL pointer dereference, address: 0000000000000018 RIP: 0010:__power_supply_is_supplied_by+0xb/0xb0 Call Trace: __power_supply_get_supplier_property+0x19/0x50 class_for_each_device+0xb1/0xe0 power_supply_get_property_from_supplier+0x2e/0x50 bq25890_charger_external_power_changed+0x38/0x1b0 [bq25890_charger] __power_supply_changed_work+0x30/0x40 class_for_each_device+0xb1/0xe0 power_supply_changed_work+0x5f/0xe0 Fixing this is easy. The external_power_changed callback gets passed the power_supply which will eventually get stored in bq->charger, so bq25890_charger_external_power_changed() can simply directly use the passed in psy argument which is always valid. Fixes: c79dce5ba4b5 ("power: supply: bq25890: On the bq25892 set the IINLIM based on external charger detection") Cc: stable@vger.kernel.org Cc: Marek Vasut Signed-off-by: Hans de Goede Signed-off-by: Sebastian Reichel Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/power/supply/bq25890_charger.c b/drivers/power/supply/bq25890_charger.c index 0e15302b8df22..f9ee843c8082f 100644 --- a/drivers/power/supply/bq25890_charger.c +++ b/drivers/power/supply/bq25890_charger.c @@ -650,7 +650,7 @@ static void bq25890_charger_external_power_changed(struct power_supply *psy) if (bq->chip_version != BQ25892) return; - ret = power_supply_get_property_from_supplier(bq->charger, + ret = power_supply_get_property_from_supplier(psy, POWER_SUPPLY_PROP_USB_TYPE, &val); if (ret)