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power_supply: Change ownership from driver to core
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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 : [<c034b0b4>]    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] [<c034b0b4>] (charger_get_property) from [<c0346864>] (power_supply_show_property+0x48/0x20c)
[   55.939286] [<c0346864>] (power_supply_show_property) from [<c027f25c>] (dev_attr_show+0x1c/0x48)
[   55.948130] [<c027f25c>] (dev_attr_show) from [<c0146218>] (sysfs_kf_seq_show+0x84/0x104)
[   55.956298] [<c0146218>] (sysfs_kf_seq_show) from [<c0144c78>] (kernfs_seq_show+0x24/0x28)
[   55.964536] [<c0144c78>] (kernfs_seq_show) from [<c0107f90>] (seq_read+0x1b0/0x484)
[   55.972172] [<c0107f90>] (seq_read) from [<c00e53dc>] (__vfs_read+0x18/0x4c)
[   55.979188] [<c00e53dc>] (__vfs_read) from [<c00e548c>] (vfs_read+0x7c/0x100)
[   55.986304] [<c00e548c>] (vfs_read) from [<c00e5550>] (SyS_read+0x40/0x8c)
[   55.993164] [<c00e5550>] (SyS_read) from [<c000f1a0>] (ret_fast_syscall+0x0/0x48)
[   56.000626] Code: bad PC value
[   56.011652] ---[ end trace 7b64343fbdae8ef1 ]---

Signed-off-by: Krzysztof Kozlowski <[email protected]>
Reviewed-by: Bartlomiej Zolnierkiewicz <[email protected]>

[for the nvec part]
Reviewed-by: Marc Dietrich <[email protected]>

[for compal-laptop.c]
Acked-by: Darren Hart <[email protected]>

[for the mfd part]
Acked-by: Lee Jones <[email protected]>

[for the hid part]
Acked-by: Jiri Kosina <[email protected]>

[for the acpi part]
Acked-by: Rafael J. Wysocki <[email protected]>

Signed-off-by: Sebastian Reichel <[email protected]>
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@krzk @sre
krzk authored and sre committed Mar 13, 2015
1 parent b70229b commit 297d716
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Showing 82 changed files with 2,296 additions and 1,839 deletions.
4 changes: 2 additions & 2 deletions arch/x86/platform/olpc/olpc-xo1-sci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,7 @@ static void battery_status_changed(void)

if (psy) {
power_supply_changed(psy);
put_device(psy->dev);
put_device(&psy->dev);
}
}

Expand All @@ -71,7 +71,7 @@ static void ac_status_changed(void)

if (psy) {
power_supply_changed(psy);
put_device(psy->dev);
put_device(&psy->dev);
}
}

Expand Down
4 changes: 2 additions & 2 deletions arch/x86/platform/olpc/olpc-xo15-sci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -83,7 +83,7 @@ static void battery_status_changed(void)

if (psy) {
power_supply_changed(psy);
put_device(psy->dev);
put_device(&psy->dev);
}
}

Expand All @@ -93,7 +93,7 @@ static void ac_status_changed(void)

if (psy) {
power_supply_changed(psy);
put_device(psy->dev);
put_device(&psy->dev);
}
}

Expand Down
32 changes: 19 additions & 13 deletions drivers/acpi/ac.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -95,13 +95,14 @@ static struct acpi_driver acpi_ac_driver = {
};

struct acpi_ac {
struct power_supply charger;
struct power_supply *charger;
struct power_supply_desc charger_desc;
struct acpi_device * device;
unsigned long long state;
struct notifier_block battery_nb;
};

#define to_acpi_ac(x) container_of(x, struct acpi_ac, charger)
#define to_acpi_ac(x) power_supply_get_drvdata(x)

#ifdef CONFIG_ACPI_PROCFS_POWER
static const struct file_operations acpi_ac_fops = {
Expand Down Expand Up @@ -275,7 +276,7 @@ static void acpi_ac_notify(struct acpi_device *device, u32 event)
dev_name(&device->dev), event,
(u32) ac->state);
acpi_notifier_call_chain(device, event, (u32) ac->state);
kobject_uevent(&ac->charger.dev->kobj, KOBJ_CHANGE);
kobject_uevent(&ac->charger->dev.kobj, KOBJ_CHANGE);
}

return;
Expand Down Expand Up @@ -321,6 +322,7 @@ static struct dmi_system_id ac_dmi_table[] = {

static int acpi_ac_add(struct acpi_device *device)
{
struct power_supply_config psy_cfg = {};
int result = 0;
struct acpi_ac *ac = NULL;

Expand All @@ -341,19 +343,24 @@ static int acpi_ac_add(struct acpi_device *device)
if (result)
goto end;

ac->charger.name = acpi_device_bid(device);
psy_cfg.drv_data = ac;

ac->charger_desc.name = acpi_device_bid(device);
#ifdef CONFIG_ACPI_PROCFS_POWER
result = acpi_ac_add_fs(ac);
if (result)
goto end;
#endif
ac->charger.type = POWER_SUPPLY_TYPE_MAINS;
ac->charger.properties = ac_props;
ac->charger.num_properties = ARRAY_SIZE(ac_props);
ac->charger.get_property = get_ac_property;
result = power_supply_register(&ac->device->dev, &ac->charger, NULL);
if (result)
ac->charger_desc.type = POWER_SUPPLY_TYPE_MAINS;
ac->charger_desc.properties = ac_props;
ac->charger_desc.num_properties = ARRAY_SIZE(ac_props);
ac->charger_desc.get_property = get_ac_property;
ac->charger = power_supply_register(&ac->device->dev,
&ac->charger_desc, &psy_cfg);
if (IS_ERR(ac->charger)) {
result = PTR_ERR(ac->charger);
goto end;
}

printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
acpi_device_name(device), acpi_device_bid(device),
Expand Down Expand Up @@ -390,7 +397,7 @@ static int acpi_ac_resume(struct device *dev)
if (acpi_ac_get_state(ac))
return 0;
if (old_state != ac->state)
kobject_uevent(&ac->charger.dev->kobj, KOBJ_CHANGE);
kobject_uevent(&ac->charger->dev.kobj, KOBJ_CHANGE);
return 0;
}
#else
Expand All @@ -407,8 +414,7 @@ static int acpi_ac_remove(struct acpi_device *device)

ac = acpi_driver_data(device);

if (ac->charger.dev)
power_supply_unregister(&ac->charger);
power_supply_unregister(ac->charger);
unregister_acpi_notifier(&ac->battery_nb);

#ifdef CONFIG_ACPI_PROCFS_POWER
Expand Down
55 changes: 30 additions & 25 deletions drivers/acpi/battery.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -117,7 +117,8 @@ enum {
struct acpi_battery {
struct mutex lock;
struct mutex sysfs_lock;
struct power_supply bat;
struct power_supply *bat;
struct power_supply_desc bat_desc;
struct acpi_device *device;
struct notifier_block pm_nb;
unsigned long update_time;
Expand Down Expand Up @@ -149,7 +150,7 @@ struct acpi_battery {
unsigned long flags;
};

#define to_acpi_battery(x) container_of(x, struct acpi_battery, bat)
#define to_acpi_battery(x) power_supply_get_drvdata(x)

static inline int acpi_battery_present(struct acpi_battery *battery)
{
Expand Down Expand Up @@ -608,41 +609,45 @@ static struct device_attribute alarm_attr = {

static int sysfs_add_battery(struct acpi_battery *battery)
{
int result;
struct power_supply_config psy_cfg = { .drv_data = battery, };

if (battery->power_unit == ACPI_BATTERY_POWER_UNIT_MA) {
battery->bat.properties = charge_battery_props;
battery->bat.num_properties =
battery->bat_desc.properties = charge_battery_props;
battery->bat_desc.num_properties =
ARRAY_SIZE(charge_battery_props);
} else {
battery->bat.properties = energy_battery_props;
battery->bat.num_properties =
battery->bat_desc.properties = energy_battery_props;
battery->bat_desc.num_properties =
ARRAY_SIZE(energy_battery_props);
}

battery->bat.name = acpi_device_bid(battery->device);
battery->bat.type = POWER_SUPPLY_TYPE_BATTERY;
battery->bat.get_property = acpi_battery_get_property;
battery->bat_desc.name = acpi_device_bid(battery->device);
battery->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
battery->bat_desc.get_property = acpi_battery_get_property;

result = power_supply_register_no_ws(&battery->device->dev,
&battery->bat, NULL);
battery->bat = power_supply_register_no_ws(&battery->device->dev,
&battery->bat_desc, &psy_cfg);

if (result)
if (IS_ERR(battery->bat)) {
int result = PTR_ERR(battery->bat);

battery->bat = NULL;
return result;
return device_create_file(battery->bat.dev, &alarm_attr);
}
return device_create_file(&battery->bat->dev, &alarm_attr);
}

static void sysfs_remove_battery(struct acpi_battery *battery)
{
mutex_lock(&battery->sysfs_lock);
if (!battery->bat.dev) {
if (!battery->bat) {
mutex_unlock(&battery->sysfs_lock);
return;
}

device_remove_file(battery->bat.dev, &alarm_attr);
power_supply_unregister(&battery->bat);
battery->bat.dev = NULL;
device_remove_file(&battery->bat->dev, &alarm_attr);
power_supply_unregister(battery->bat);
battery->bat = NULL;
mutex_unlock(&battery->sysfs_lock);
}

Expand Down Expand Up @@ -739,7 +744,7 @@ static int acpi_battery_update(struct acpi_battery *battery, bool resume)
return result;
acpi_battery_init_alarm(battery);
}
if (!battery->bat.dev) {
if (!battery->bat) {
result = sysfs_add_battery(battery);
if (result)
return result;
Expand All @@ -765,7 +770,7 @@ static void acpi_battery_refresh(struct acpi_battery *battery)
{
int power_unit;

if (!battery->bat.dev)
if (!battery->bat)
return;

power_unit = battery->power_unit;
Expand Down Expand Up @@ -1063,11 +1068,11 @@ static void acpi_battery_remove_fs(struct acpi_device *device)
static void acpi_battery_notify(struct acpi_device *device, u32 event)
{
struct acpi_battery *battery = acpi_driver_data(device);
struct device *old;
struct power_supply *old;

if (!battery)
return;
old = battery->bat.dev;
old = battery->bat;
/*
* On Acer Aspire V5-573G notifications are sometimes triggered too
* early. For example, when AC is unplugged and notification is
Expand All @@ -1084,8 +1089,8 @@ static void acpi_battery_notify(struct acpi_device *device, u32 event)
acpi_battery_present(battery));
acpi_notifier_call_chain(device, event, acpi_battery_present(battery));
/* acpi_battery_update could remove power_supply object */
if (old && battery->bat.dev)
power_supply_changed(&battery->bat);
if (old && battery->bat)
power_supply_changed(battery->bat);
}

static int battery_notify(struct notifier_block *nb,
Expand All @@ -1101,7 +1106,7 @@ static int battery_notify(struct notifier_block *nb,
if (!acpi_battery_present(battery))
return 0;

if (!battery->bat.dev) {
if (battery->bat) {
result = acpi_battery_get_info(battery);
if (result)
return result;
Expand Down
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