Skip to content

Commit 297d716

Browse files
krzksre
krzk
authored and
sre
committed
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 raspberrypi#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]>
1 parent b70229b commit 297d716

Some content is hidden

Large Commits have some content hidden by default. Use the searchbox below for content that may be hidden.

82 files changed

+2296
-1839
lines changed

‎arch/x86/platform/olpc/olpc-xo1-sci.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -61,7 +61,7 @@ static void battery_status_changed(void)
6161

6262
if (psy) {
6363
power_supply_changed(psy);
64-
put_device(psy->dev);
64+
put_device(&psy->dev);
6565
}
6666
}
6767

@@ -71,7 +71,7 @@ static void ac_status_changed(void)
7171

7272
if (psy) {
7373
power_supply_changed(psy);
74-
put_device(psy->dev);
74+
put_device(&psy->dev);
7575
}
7676
}
7777

‎arch/x86/platform/olpc/olpc-xo15-sci.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -83,7 +83,7 @@ static void battery_status_changed(void)
8383

8484
if (psy) {
8585
power_supply_changed(psy);
86-
put_device(psy->dev);
86+
put_device(&psy->dev);
8787
}
8888
}
8989

@@ -93,7 +93,7 @@ static void ac_status_changed(void)
9393

9494
if (psy) {
9595
power_supply_changed(psy);
96-
put_device(psy->dev);
96+
put_device(&psy->dev);
9797
}
9898
}
9999

‎drivers/acpi/ac.c

Lines changed: 19 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -95,13 +95,14 @@ static struct acpi_driver acpi_ac_driver = {
9595
};
9696

9797
struct acpi_ac {
98-
struct power_supply charger;
98+
struct power_supply *charger;
99+
struct power_supply_desc charger_desc;
99100
struct acpi_device * device;
100101
unsigned long long state;
101102
struct notifier_block battery_nb;
102103
};
103104

104-
#define to_acpi_ac(x) container_of(x, struct acpi_ac, charger)
105+
#define to_acpi_ac(x) power_supply_get_drvdata(x)
105106

106107
#ifdef CONFIG_ACPI_PROCFS_POWER
107108
static const struct file_operations acpi_ac_fops = {
@@ -275,7 +276,7 @@ static void acpi_ac_notify(struct acpi_device *device, u32 event)
275276
dev_name(&device->dev), event,
276277
(u32) ac->state);
277278
acpi_notifier_call_chain(device, event, (u32) ac->state);
278-
kobject_uevent(&ac->charger.dev->kobj, KOBJ_CHANGE);
279+
kobject_uevent(&ac->charger->dev.kobj, KOBJ_CHANGE);
279280
}
280281

281282
return;
@@ -321,6 +322,7 @@ static struct dmi_system_id ac_dmi_table[] = {
321322

322323
static int acpi_ac_add(struct acpi_device *device)
323324
{
325+
struct power_supply_config psy_cfg = {};
324326
int result = 0;
325327
struct acpi_ac *ac = NULL;
326328

@@ -341,19 +343,24 @@ static int acpi_ac_add(struct acpi_device *device)
341343
if (result)
342344
goto end;
343345

344-
ac->charger.name = acpi_device_bid(device);
346+
psy_cfg.drv_data = ac;
347+
348+
ac->charger_desc.name = acpi_device_bid(device);
345349
#ifdef CONFIG_ACPI_PROCFS_POWER
346350
result = acpi_ac_add_fs(ac);
347351
if (result)
348352
goto end;
349353
#endif
350-
ac->charger.type = POWER_SUPPLY_TYPE_MAINS;
351-
ac->charger.properties = ac_props;
352-
ac->charger.num_properties = ARRAY_SIZE(ac_props);
353-
ac->charger.get_property = get_ac_property;
354-
result = power_supply_register(&ac->device->dev, &ac->charger, NULL);
355-
if (result)
354+
ac->charger_desc.type = POWER_SUPPLY_TYPE_MAINS;
355+
ac->charger_desc.properties = ac_props;
356+
ac->charger_desc.num_properties = ARRAY_SIZE(ac_props);
357+
ac->charger_desc.get_property = get_ac_property;
358+
ac->charger = power_supply_register(&ac->device->dev,
359+
&ac->charger_desc, &psy_cfg);
360+
if (IS_ERR(ac->charger)) {
361+
result = PTR_ERR(ac->charger);
356362
goto end;
363+
}
357364

358365
printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
359366
acpi_device_name(device), acpi_device_bid(device),
@@ -390,7 +397,7 @@ static int acpi_ac_resume(struct device *dev)
390397
if (acpi_ac_get_state(ac))
391398
return 0;
392399
if (old_state != ac->state)
393-
kobject_uevent(&ac->charger.dev->kobj, KOBJ_CHANGE);
400+
kobject_uevent(&ac->charger->dev.kobj, KOBJ_CHANGE);
394401
return 0;
395402
}
396403
#else
@@ -407,8 +414,7 @@ static int acpi_ac_remove(struct acpi_device *device)
407414

408415
ac = acpi_driver_data(device);
409416

410-
if (ac->charger.dev)
411-
power_supply_unregister(&ac->charger);
417+
power_supply_unregister(ac->charger);
412418
unregister_acpi_notifier(&ac->battery_nb);
413419

414420
#ifdef CONFIG_ACPI_PROCFS_POWER

‎drivers/acpi/battery.c

Lines changed: 30 additions & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -117,7 +117,8 @@ enum {
117117
struct acpi_battery {
118118
struct mutex lock;
119119
struct mutex sysfs_lock;
120-
struct power_supply bat;
120+
struct power_supply *bat;
121+
struct power_supply_desc bat_desc;
121122
struct acpi_device *device;
122123
struct notifier_block pm_nb;
123124
unsigned long update_time;
@@ -149,7 +150,7 @@ struct acpi_battery {
149150
unsigned long flags;
150151
};
151152

152-
#define to_acpi_battery(x) container_of(x, struct acpi_battery, bat)
153+
#define to_acpi_battery(x) power_supply_get_drvdata(x)
153154

154155
static inline int acpi_battery_present(struct acpi_battery *battery)
155156
{
@@ -608,41 +609,45 @@ static struct device_attribute alarm_attr = {
608609

609610
static int sysfs_add_battery(struct acpi_battery *battery)
610611
{
611-
int result;
612+
struct power_supply_config psy_cfg = { .drv_data = battery, };
612613

613614
if (battery->power_unit == ACPI_BATTERY_POWER_UNIT_MA) {
614-
battery->bat.properties = charge_battery_props;
615-
battery->bat.num_properties =
615+
battery->bat_desc.properties = charge_battery_props;
616+
battery->bat_desc.num_properties =
616617
ARRAY_SIZE(charge_battery_props);
617618
} else {
618-
battery->bat.properties = energy_battery_props;
619-
battery->bat.num_properties =
619+
battery->bat_desc.properties = energy_battery_props;
620+
battery->bat_desc.num_properties =
620621
ARRAY_SIZE(energy_battery_props);
621622
}
622623

623-
battery->bat.name = acpi_device_bid(battery->device);
624-
battery->bat.type = POWER_SUPPLY_TYPE_BATTERY;
625-
battery->bat.get_property = acpi_battery_get_property;
624+
battery->bat_desc.name = acpi_device_bid(battery->device);
625+
battery->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
626+
battery->bat_desc.get_property = acpi_battery_get_property;
626627

627-
result = power_supply_register_no_ws(&battery->device->dev,
628-
&battery->bat, NULL);
628+
battery->bat = power_supply_register_no_ws(&battery->device->dev,
629+
&battery->bat_desc, &psy_cfg);
629630

630-
if (result)
631+
if (IS_ERR(battery->bat)) {
632+
int result = PTR_ERR(battery->bat);
633+
634+
battery->bat = NULL;
631635
return result;
632-
return device_create_file(battery->bat.dev, &alarm_attr);
636+
}
637+
return device_create_file(&battery->bat->dev, &alarm_attr);
633638
}
634639

635640
static void sysfs_remove_battery(struct acpi_battery *battery)
636641
{
637642
mutex_lock(&battery->sysfs_lock);
638-
if (!battery->bat.dev) {
643+
if (!battery->bat) {
639644
mutex_unlock(&battery->sysfs_lock);
640645
return;
641646
}
642647

643-
device_remove_file(battery->bat.dev, &alarm_attr);
644-
power_supply_unregister(&battery->bat);
645-
battery->bat.dev = NULL;
648+
device_remove_file(&battery->bat->dev, &alarm_attr);
649+
power_supply_unregister(battery->bat);
650+
battery->bat = NULL;
646651
mutex_unlock(&battery->sysfs_lock);
647652
}
648653

@@ -739,7 +744,7 @@ static int acpi_battery_update(struct acpi_battery *battery, bool resume)
739744
return result;
740745
acpi_battery_init_alarm(battery);
741746
}
742-
if (!battery->bat.dev) {
747+
if (!battery->bat) {
743748
result = sysfs_add_battery(battery);
744749
if (result)
745750
return result;
@@ -765,7 +770,7 @@ static void acpi_battery_refresh(struct acpi_battery *battery)
765770
{
766771
int power_unit;
767772

768-
if (!battery->bat.dev)
773+
if (!battery->bat)
769774
return;
770775

771776
power_unit = battery->power_unit;
@@ -1063,11 +1068,11 @@ static void acpi_battery_remove_fs(struct acpi_device *device)
10631068
static void acpi_battery_notify(struct acpi_device *device, u32 event)
10641069
{
10651070
struct acpi_battery *battery = acpi_driver_data(device);
1066-
struct device *old;
1071+
struct power_supply *old;
10671072

10681073
if (!battery)
10691074
return;
1070-
old = battery->bat.dev;
1075+
old = battery->bat;
10711076
/*
10721077
* On Acer Aspire V5-573G notifications are sometimes triggered too
10731078
* early. For example, when AC is unplugged and notification is
@@ -1084,8 +1089,8 @@ static void acpi_battery_notify(struct acpi_device *device, u32 event)
10841089
acpi_battery_present(battery));
10851090
acpi_notifier_call_chain(device, event, acpi_battery_present(battery));
10861091
/* acpi_battery_update could remove power_supply object */
1087-
if (old && battery->bat.dev)
1088-
power_supply_changed(&battery->bat);
1092+
if (old && battery->bat)
1093+
power_supply_changed(battery->bat);
10891094
}
10901095

10911096
static int battery_notify(struct notifier_block *nb,
@@ -1101,7 +1106,7 @@ static int battery_notify(struct notifier_block *nb,
11011106
if (!acpi_battery_present(battery))
11021107
return 0;
11031108

1104-
if (!battery->bat.dev) {
1109+
if (battery->bat) {
11051110
result = acpi_battery_get_info(battery);
11061111
if (result)
11071112
return result;

0 commit comments

Comments
 (0)