On Mon, 23 Feb 2015, Krzysztof Kozlowski wrote: > Change the ownership of power_supply structure from each driver > implementing the class to the power supply core. > > The patch changes power_supply_register() function thus all drivers > implementing power supply class are adjusted. > > Each driver provides the implementation of power supply. However it > should not be the owner of power supply class instance because it is > exposed by core to other subsystems with power_supply_get_by_name(). > These other subsystems have no knowledge when the driver will unregister > the power supply. This leads to several issues when driver is unbound - > mostly because user of power supply accesses freed memory. > > Instead let the core own the instance of struct 'power_supply'. Other > users of this power supply will still access valid memory because it > will be freed when device reference count reaches 0. Currently this > means "it will leak" but power_supply_put() call in next patches will > solve it. > > This solves invalid memory references in following race condition > scenario: > > Thread 1: charger manager > Thread 2: power supply driver, used by charger manager > > THREAD 1 (charger manager) THREAD 2 (power supply driver) > ========================== ============================== > psy = power_supply_get_by_name() > Driver unbind, .remove > power_supply_unregister() > Device fully removed [...] > include/linux/mfd/abx500/ux500_chargalg.h | 11 +- > include/linux/mfd/rt5033.h | 2 +- > include/linux/mfd/wm8350/supply.h | 6 +- Acked-by: Lee Jones <lee.jones@xxxxxxxxxx> -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
