From: Hans de Goede <hdegoede@xxxxxxxxxx>
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
<snip>
RIP: 0010:__power_supply_is_supplied_by+0xb/0xb0
<snip>
Call Trace:
<TASK>
__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
<snip>
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: eab25b4f93aa ("power: supply: bq25890: On the bq25892 set the IINLIM based on external charger detection")
Cc: stable@xxxxxxxxxxxxxxx
Cc: Marek Vasut <marex@xxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/power/supply/bq25890_charger.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/power/supply/bq25890_charger.c
+++ b/drivers/power/supply/bq25890_charger.c
@@ -750,7 +750,7 @@ static void bq25890_charger_external_pow
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)
