From 297d716f6260cc9421d971b124ca196b957ee458 Mon Sep 17 00:00:00 2001 From: Krzysztof Kozlowski Date: Thu, 12 Mar 2015 08:44:11 +0100 Subject: power_supply: Change ownership from driver to core 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 psy->get_property() The 'get_property' call is executed in invalid context because the driver was unbound and struct 'power_supply' memory was freed. This could be observed easily with charger manager driver (here compiled with max17040 fuel gauge): $ cat /sys/devices/virtual/power_supply/cm-battery/capacity & $ echo "1-0036" > /sys/bus/i2c/drivers/max17040/unbind [ 55.725123] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 55.732584] pgd = d98d4000 [ 55.734060] [00000000] *pgd=5afa2831, *pte=00000000, *ppte=00000000 [ 55.740318] Internal error: Oops: 80000007 [#1] PREEMPT SMP ARM [ 55.746210] Modules linked in: [ 55.749259] CPU: 1 PID: 2936 Comm: cat Tainted: G W 3.19.0-rc1-next-20141226-00048-gf79f475f3c44-dirty #1496 [ 55.760190] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 55.766270] task: d9b76f00 ti: daf54000 task.ti: daf54000 [ 55.771647] PC is at 0x0 [ 55.774182] LR is at charger_get_property+0x2f4/0x36c [ 55.779201] pc : [<00000000>] lr : [] psr: 60000013 [ 55.779201] sp : daf55e90 ip : 00000003 fp : 00000000 [ 55.790657] r10: 00000000 r9 : c06e2878 r8 : d9b26c68 [ 55.795865] r7 : dad81610 r6 : daec7410 r5 : daf55ebc r4 : 00000000 [ 55.802367] r3 : 00000000 r2 : daf55ebc r1 : 0000002a r0 : d9b26c68 [ 55.808879] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user [ 55.815994] Control: 10c5387d Table: 598d406a DAC: 00000015 [ 55.821723] Process cat (pid: 2936, stack limit = 0xdaf54210) [ 55.827451] Stack: (0xdaf55e90 to 0xdaf56000) [ 55.831795] 5e80: 60000013 c01459c4 0000002a c06f8ef8 [ 55.839956] 5ea0: db651000 c06f8ef8 daebac00 c04cb668 daebac08 c0346864 00000000 c01459c4 [ 55.848115] 5ec0: d99eaa80 c06f8ef8 00000fff 00001000 db651000 c027f25c c027f240 d99eaa80 [ 55.856274] 5ee0: d9a06c00 c0146218 daf55f18 00001000 d99eaa80 db4c18c0 00000001 00000001 [ 55.864468] 5f00: daf55f80 c0144c78 c0144c54 c0107f90 00015000 d99eaab0 00000000 00000000 [ 55.872603] 5f20: 000051c7 00000000 db4c18c0 c04a9370 00015000 00001000 daf55f80 00001000 [ 55.880763] 5f40: daf54000 00015000 00000000 c00e53dc db4c18c0 c00e548c 0000000d 00008124 [ 55.888937] 5f60: 00000001 00000000 00000000 db4c18c0 db4c18c0 00001000 00015000 c00e5550 [ 55.897099] 5f80: 00000000 00000000 00001000 00001000 00015000 00000003 00000003 c000f364 [ 55.905239] 5fa0: 00000000 c000f1a0 00001000 00015000 00000003 00015000 00001000 0001333c [ 55.913399] 5fc0: 00001000 00015000 00000003 00000003 00000002 00000000 00000000 00000000 [ 55.921560] 5fe0: 7fffe000 be999850 0000a225 b6f3c19c 60000010 00000003 00000000 00000000 [ 55.929744] [] (charger_get_property) from [] (power_supply_show_property+0x48/0x20c) [ 55.939286] [] (power_supply_show_property) from [] (dev_attr_show+0x1c/0x48) [ 55.948130] [] (dev_attr_show) from [] (sysfs_kf_seq_show+0x84/0x104) [ 55.956298] [] (sysfs_kf_seq_show) from [] (kernfs_seq_show+0x24/0x28) [ 55.964536] [] (kernfs_seq_show) from [] (seq_read+0x1b0/0x484) [ 55.972172] [] (seq_read) from [] (__vfs_read+0x18/0x4c) [ 55.979188] [] (__vfs_read) from [] (vfs_read+0x7c/0x100) [ 55.986304] [] (vfs_read) from [] (SyS_read+0x40/0x8c) [ 55.993164] [] (SyS_read) from [] (ret_fast_syscall+0x0/0x48) [ 56.000626] Code: bad PC value [ 56.011652] ---[ end trace 7b64343fbdae8ef1 ]--- Signed-off-by: Krzysztof Kozlowski Reviewed-by: Bartlomiej Zolnierkiewicz [for the nvec part] Reviewed-by: Marc Dietrich [for compal-laptop.c] Acked-by: Darren Hart [for the mfd part] Acked-by: Lee Jones [for the hid part] Acked-by: Jiri Kosina [for the acpi part] Acked-by: Rafael J. Wysocki Signed-off-by: Sebastian Reichel --- drivers/power/bq24190_charger.c | 103 +++++++++++++++++++--------------------- 1 file changed, 49 insertions(+), 54 deletions(-) (limited to 'drivers/power/bq24190_charger.c') diff --git a/drivers/power/bq24190_charger.c b/drivers/power/bq24190_charger.c index 54eb58485d55..407c4af83891 100644 --- a/drivers/power/bq24190_charger.c +++ b/drivers/power/bq24190_charger.c @@ -152,8 +152,8 @@ struct bq24190_dev_info { struct i2c_client *client; struct device *dev; - struct power_supply charger; - struct power_supply battery; + struct power_supply *charger; + struct power_supply *battery; char model_name[I2C_NAME_SIZE]; kernel_ulong_t model; unsigned int gpio_int; @@ -423,8 +423,7 @@ static ssize_t bq24190_sysfs_show(struct device *dev, struct device_attribute *attr, char *buf) { struct power_supply *psy = dev_get_drvdata(dev); - struct bq24190_dev_info *bdi = - container_of(psy, struct bq24190_dev_info, charger); + struct bq24190_dev_info *bdi = power_supply_get_drvdata(psy); struct bq24190_sysfs_field_info *info; int ret; u8 v; @@ -444,8 +443,7 @@ static ssize_t bq24190_sysfs_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct power_supply *psy = dev_get_drvdata(dev); - struct bq24190_dev_info *bdi = - container_of(psy, struct bq24190_dev_info, charger); + struct bq24190_dev_info *bdi = power_supply_get_drvdata(psy); struct bq24190_sysfs_field_info *info; int ret; u8 v; @@ -469,13 +467,13 @@ static int bq24190_sysfs_create_group(struct bq24190_dev_info *bdi) { bq24190_sysfs_init_attrs(); - return sysfs_create_group(&bdi->charger.dev->kobj, + return sysfs_create_group(&bdi->charger->dev.kobj, &bq24190_sysfs_attr_group); } static void bq24190_sysfs_remove_group(struct bq24190_dev_info *bdi) { - sysfs_remove_group(&bdi->charger.dev->kobj, &bq24190_sysfs_attr_group); + sysfs_remove_group(&bdi->charger->dev.kobj, &bq24190_sysfs_attr_group); } #else static int bq24190_sysfs_create_group(struct bq24190_dev_info *bdi) @@ -807,8 +805,7 @@ static int bq24190_charger_set_voltage(struct bq24190_dev_info *bdi, static int bq24190_charger_get_property(struct power_supply *psy, enum power_supply_property psp, union power_supply_propval *val) { - struct bq24190_dev_info *bdi = - container_of(psy, struct bq24190_dev_info, charger); + struct bq24190_dev_info *bdi = power_supply_get_drvdata(psy); int ret; dev_dbg(bdi->dev, "prop: %d\n", psp); @@ -861,8 +858,7 @@ static int bq24190_charger_set_property(struct power_supply *psy, enum power_supply_property psp, const union power_supply_propval *val) { - struct bq24190_dev_info *bdi = - container_of(psy, struct bq24190_dev_info, charger); + struct bq24190_dev_info *bdi = power_supply_get_drvdata(psy); int ret; dev_dbg(bdi->dev, "prop: %d\n", psp); @@ -922,18 +918,15 @@ static char *bq24190_charger_supplied_to[] = { "main-battery", }; -static void bq24190_charger_init(struct power_supply *charger) -{ - charger->name = "bq24190-charger"; - charger->type = POWER_SUPPLY_TYPE_USB; - charger->properties = bq24190_charger_properties; - charger->num_properties = ARRAY_SIZE(bq24190_charger_properties); - charger->supplied_to = bq24190_charger_supplied_to; - charger->num_supplicants = ARRAY_SIZE(bq24190_charger_supplied_to); - charger->get_property = bq24190_charger_get_property; - charger->set_property = bq24190_charger_set_property; - charger->property_is_writeable = bq24190_charger_property_is_writeable; -} +static const struct power_supply_desc bq24190_charger_desc = { + .name = "bq24190-charger", + .type = POWER_SUPPLY_TYPE_USB, + .properties = bq24190_charger_properties, + .num_properties = ARRAY_SIZE(bq24190_charger_properties), + .get_property = bq24190_charger_get_property, + .set_property = bq24190_charger_set_property, + .property_is_writeable = bq24190_charger_property_is_writeable, +}; /* Battery power supply property routines */ @@ -1102,8 +1095,7 @@ static int bq24190_battery_set_temp_alert_max(struct bq24190_dev_info *bdi, static int bq24190_battery_get_property(struct power_supply *psy, enum power_supply_property psp, union power_supply_propval *val) { - struct bq24190_dev_info *bdi = - container_of(psy, struct bq24190_dev_info, battery); + struct bq24190_dev_info *bdi = power_supply_get_drvdata(psy); int ret; dev_dbg(bdi->dev, "prop: %d\n", psp); @@ -1144,8 +1136,7 @@ static int bq24190_battery_set_property(struct power_supply *psy, enum power_supply_property psp, const union power_supply_propval *val) { - struct bq24190_dev_info *bdi = - container_of(psy, struct bq24190_dev_info, battery); + struct bq24190_dev_info *bdi = power_supply_get_drvdata(psy); int ret; dev_dbg(bdi->dev, "prop: %d\n", psp); @@ -1193,16 +1184,15 @@ static enum power_supply_property bq24190_battery_properties[] = { POWER_SUPPLY_PROP_SCOPE, }; -static void bq24190_battery_init(struct power_supply *battery) -{ - battery->name = "bq24190-battery"; - battery->type = POWER_SUPPLY_TYPE_BATTERY; - battery->properties = bq24190_battery_properties; - battery->num_properties = ARRAY_SIZE(bq24190_battery_properties); - battery->get_property = bq24190_battery_get_property; - battery->set_property = bq24190_battery_set_property; - battery->property_is_writeable = bq24190_battery_property_is_writeable; -} +static const struct power_supply_desc bq24190_battery_desc = { + .name = "bq24190-battery", + .type = POWER_SUPPLY_TYPE_BATTERY, + .properties = bq24190_battery_properties, + .num_properties = ARRAY_SIZE(bq24190_battery_properties), + .get_property = bq24190_battery_get_property, + .set_property = bq24190_battery_set_property, + .property_is_writeable = bq24190_battery_property_is_writeable, +}; static irqreturn_t bq24190_irq_handler_thread(int irq, void *data) { @@ -1269,8 +1259,8 @@ static irqreturn_t bq24190_irq_handler_thread(int irq, void *data) * interrupt received). */ if (alert_userspace && !bdi->first_time) { - power_supply_changed(&bdi->charger); - power_supply_changed(&bdi->battery); + power_supply_changed(bdi->charger); + power_supply_changed(bdi->battery); bdi->first_time = false; } @@ -1362,6 +1352,7 @@ static int bq24190_probe(struct i2c_client *client, struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); struct device *dev = &client->dev; struct bq24190_platform_data *pdata = client->dev.platform_data; + struct power_supply_config charger_cfg = {}, battery_cfg = {}; struct bq24190_dev_info *bdi; int ret; @@ -1416,19 +1407,23 @@ static int bq24190_probe(struct i2c_client *client, goto out2; } - bq24190_charger_init(&bdi->charger); - - ret = power_supply_register(dev, &bdi->charger, NULL); - if (ret) { + charger_cfg.drv_data = bdi; + charger_cfg.supplied_to = bq24190_charger_supplied_to; + charger_cfg.num_supplicants = ARRAY_SIZE(bq24190_charger_supplied_to), + bdi->charger = power_supply_register(dev, &bq24190_charger_desc, + &charger_cfg); + if (IS_ERR(bdi->charger)) { dev_err(dev, "Can't register charger\n"); + ret = PTR_ERR(bdi->charger); goto out2; } - bq24190_battery_init(&bdi->battery); - - ret = power_supply_register(dev, &bdi->battery, NULL); - if (ret) { + battery_cfg.drv_data = bdi; + bdi->battery = power_supply_register(dev, &bq24190_battery_desc, + &battery_cfg); + if (IS_ERR(bdi->battery)) { dev_err(dev, "Can't register battery\n"); + ret = PTR_ERR(bdi->battery); goto out3; } @@ -1441,9 +1436,9 @@ static int bq24190_probe(struct i2c_client *client, return 0; out4: - power_supply_unregister(&bdi->battery); + power_supply_unregister(bdi->battery); out3: - power_supply_unregister(&bdi->charger); + power_supply_unregister(bdi->charger); out2: pm_runtime_disable(dev); out1: @@ -1462,8 +1457,8 @@ static int bq24190_remove(struct i2c_client *client) pm_runtime_put_sync(bdi->dev); bq24190_sysfs_remove_group(bdi); - power_supply_unregister(&bdi->battery); - power_supply_unregister(&bdi->charger); + power_supply_unregister(bdi->battery); + power_supply_unregister(bdi->charger); pm_runtime_disable(bdi->dev); if (bdi->gpio_int) @@ -1499,8 +1494,8 @@ static int bq24190_pm_resume(struct device *dev) pm_runtime_put_sync(bdi->dev); /* Things may have changed while suspended so alert upper layer */ - power_supply_changed(&bdi->charger); - power_supply_changed(&bdi->battery); + power_supply_changed(bdi->charger); + power_supply_changed(bdi->battery); return 0; } -- cgit v1.2.1