6.5-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Reichel sebastian.reichel@collabora.com
[ Upstream commit 3dc0bab23dba53f315c9a7b4a679e0a6d46f7c6e ]
power_supply_uevent() which is called to emit a udev event on device deletion attempts to use the power_supply_battery_info structure, which is device-managed and has been freed before this point.
Fix this by not generating all battery/charger properties when the device is about to be removed. This also avoids generating errors when trying to access the hardware in hot-unplug scenarios.
================================================================== BUG: KASAN: slab-use-after-free in power_supply_battery_info_has_prop (power_supply_core.c:872) Read of size 4 at addr 0000000062e59028 by task python3/27
Call Trace: power_supply_battery_info_has_prop (power_supply_core.c:872) power_supply_uevent (power_supply_sysfs.c:504) dev_uevent (drivers/base/core.c:2590) kobject_uevent_env (lib/kobject_uevent.c:558) kobject_uevent (lib/kobject_uevent.c:643) device_del (drivers/base/core.c:3266 drivers/base/core.c:3831) device_unregister (drivers/base/core.c:3730 drivers/base/core.c:3854) power_supply_unregister (power_supply_core.c:1608) devm_power_supply_release (power_supply_core.c:1515) release_nodes (drivers/base/devres.c:506) devres_release_group (drivers/base/devres.c:669) i2c_device_remove (drivers/i2c/i2c-core-base.c:629) device_remove (drivers/base/dd.c:570) device_release_driver_internal (drivers/base/dd.c:1274 drivers/base/dd.c:1295) device_driver_detach (drivers/base/dd.c:1332) unbind_store (drivers/base/bus.c:247) ...
Allocated by task 27: devm_kmalloc (drivers/base/devres.c:119 drivers/base/devres.c:829) power_supply_get_battery_info (include/linux/device.h:316 power_supply_core.c:626) __power_supply_register (power_supply_core.c:1408) devm_power_supply_register (power_supply_core.c:1544) bq256xx_probe (bq256xx_charger.c:1539 bq256xx_charger.c:1727) bq256xx_charger i2c_device_probe (drivers/i2c/i2c-core-base.c:584) really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658) __driver_probe_device (drivers/base/dd.c:800) device_driver_attach (drivers/base/dd.c:1128) bind_store (drivers/base/bus.c:273) ...
Freed by task 27: kfree (mm/slab_common.c:1073) release_nodes (drivers/base/devres.c:503) devres_release_all (drivers/base/devres.c:536) device_del (drivers/base/core.c:3829) device_unregister (drivers/base/core.c:3730 drivers/base/core.c:3854) power_supply_unregister (power_supply_core.c:1608) devm_power_supply_release (power_supply_core.c:1515) release_nodes (drivers/base/devres.c:506) devres_release_group (drivers/base/devres.c:669) i2c_device_remove (drivers/i2c/i2c-core-base.c:629) device_remove (drivers/base/dd.c:570) device_release_driver_internal (drivers/base/dd.c:1274 drivers/base/dd.c:1295) device_driver_detach (drivers/base/dd.c:1332) unbind_store (drivers/base/bus.c:247) ... ==================================================================
Reported-by: Vincent Whitchurch vincent.whitchurch@axis.com Fixes: 27a2195efa8d ("power: supply: core: auto-exposure of simple-battery data") Tested-by: Vincent Whitchurch vincent.whitchurch@axis.com Signed-off-by: Sebastian Reichel sebastian.reichel@collabora.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/power/supply/power_supply_sysfs.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c index 06e5b6b0e255c..d483a81560ab0 100644 --- a/drivers/power/supply/power_supply_sysfs.c +++ b/drivers/power/supply/power_supply_sysfs.c @@ -482,6 +482,13 @@ int power_supply_uevent(const struct device *dev, struct kobj_uevent_env *env) if (ret) return ret;
+ /* + * Kernel generates KOBJ_REMOVE uevent in device removal path, after + * resources have been freed. Exit early to avoid use-after-free. + */ + if (psy->removing) + return 0; + prop_buf = (char *)get_zeroed_page(GFP_KERNEL); if (!prop_buf) return -ENOMEM;