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power: supply: sc27xx: Fix external_power_changed race

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sc27xx_fgu_external_power_changed() dereferences data->battery,
which gets sets in ab8500_btemp_probe() like this:

	data->battery = devm_power_supply_register(dev, &sc27xx_fgu_desc,
                                                   &fgu_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 sc27xx_fgu_external_power_changed() may get called while
data->battery has not been set yet leading to a NULL pointer dereference.

Fixing this is easy. The external_power_changed callback gets passed
the power_supply which will eventually get stored in data->battery,
so sc27xx_fgu_external_power_changed() can simply directly use
the passed in psy argument which is always valid.

After this change sc27xx_fgu_external_power_changed() is reduced to just
"power_supply_changed(psy);" and it has the same prototype. While at it
simply replace it with making the external_power_changed callback
directly point to power_supply_changed.

Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
This commit is contained in:
Hans de Goede 2023-04-15 18:07:32 +02:00 committed by Sebastian Reichel
parent 029a443b9b
commit 4d5c129d6c
1 changed files with 1 additions and 8 deletions
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9
drivers/power/supply/sc27xx_fuel_gauge.c
View file

@ -733,13 +733,6 @@ static int sc27xx_fgu_set_property(struct power_supply *psy,
return ret;
}
static void sc27xx_fgu_external_power_changed(struct power_supply *psy)
{
struct sc27xx_fgu_data *data = power_supply_get_drvdata(psy);
power_supply_changed(data->battery);
}
static int sc27xx_fgu_property_is_writeable(struct power_supply *psy,
enum power_supply_property psp)
{
@ -774,7 +767,7 @@ static const struct power_supply_desc sc27xx_fgu_desc = {
.num_properties = ARRAY_SIZE(sc27xx_fgu_props),
.get_property = sc27xx_fgu_get_property,
.set_property = sc27xx_fgu_set_property,
.external_power_changed = sc27xx_fgu_external_power_changed,
.external_power_changed = power_supply_changed,
.property_is_writeable = sc27xx_fgu_property_is_writeable,
.no_thermal = true,
};