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 : [<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 <k.kozlowski@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

[for the nvec part]
Reviewed-by: Marc Dietrich <marvin24@gmx.de>

[for compal-laptop.c]
Acked-by: Darren Hart <dvhart@linux.intel.com>

[for the mfd part]
Acked-by: Lee Jones <lee.jones@linaro.org>

[for the hid part]
Acked-by: Jiri Kosina <jkosina@suse.cz>

[for the acpi part]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: Sebastian Reichel <sre@kernel.org>

6 files changed, 120 insertions, 97 deletions

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 6182265..5d5a8c4 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -339,7 +339,7 @@ static int hidinput_get_battery_property(struct power_supply *psy,
 					 enum power_supply_property prop,
 					 union power_supply_propval *val)
 {
-	struct hid_device *dev = container_of(psy, struct hid_device, battery);
+	struct hid_device *dev = power_supply_get_drvdata(psy);
 	int ret = 0;
 	__u8 *buf;
 
@@ -397,26 +397,32 @@ static int hidinput_get_battery_property(struct power_supply *psy,
 
 static bool hidinput_setup_battery(struct hid_device *dev, unsigned report_type, struct hid_field *field)
 {
-	struct power_supply *battery = &dev->battery;
-	int ret;
+	struct power_supply_desc *psy_desc = NULL;
+	struct power_supply_config psy_cfg = { .drv_data = dev, };
 	unsigned quirks;
 	s32 min, max;
 
 	if (field->usage->hid != HID_DC_BATTERYSTRENGTH)
 		return false;	/* no match */
 
-	if (battery->name != NULL)
+	if (dev->battery != NULL)
 		goto out;	/* already initialized? */
 
-	battery->name = kasprintf(GFP_KERNEL, "hid-%s-battery", dev->uniq);
-	if (battery->name == NULL)
+	psy_desc = kzalloc(sizeof(*psy_desc), GFP_KERNEL);
+	if (psy_desc == NULL)
 		goto out;
 
-	battery->type = POWER_SUPPLY_TYPE_BATTERY;
-	battery->properties = hidinput_battery_props;
-	battery->num_properties = ARRAY_SIZE(hidinput_battery_props);
-	battery->use_for_apm = 0;
-	battery->get_property = hidinput_get_battery_property;
+	psy_desc->name = kasprintf(GFP_KERNEL, "hid-%s-battery", dev->uniq);
+	if (psy_desc->name == NULL) {
+		kfree(psy_desc);
+		goto out;
+	}
+
+	psy_desc->type = POWER_SUPPLY_TYPE_BATTERY;
+	psy_desc->properties = hidinput_battery_props;
+	psy_desc->num_properties = ARRAY_SIZE(hidinput_battery_props);
+	psy_desc->use_for_apm = 0;
+	psy_desc->get_property = hidinput_get_battery_property;
 
 	quirks = find_battery_quirk(dev);
 
@@ -439,14 +445,16 @@ static bool hidinput_setup_battery(struct hid_device *dev, unsigned report_type,
 	dev->battery_report_type = report_type;
 	dev->battery_report_id = field->report->id;
 
-	ret = power_supply_register(&dev->dev, battery, NULL);
-	if (ret != 0) {
-		hid_warn(dev, "can't register power supply: %d\n", ret);
-		kfree(battery->name);
-		battery->name = NULL;
+	dev->battery = power_supply_register(&dev->dev, psy_desc, &psy_cfg);
+	if (IS_ERR(dev->battery)) {
+		hid_warn(dev, "can't register power supply: %ld\n",
+				PTR_ERR(dev->battery));
+		kfree(psy_desc->name);
+		kfree(psy_desc);
+		dev->battery = NULL;
 	}
 
-	power_supply_powers(battery, &dev->dev);
+	power_supply_powers(dev->battery, &dev->dev);
 
 out:
 	return true;
@@ -454,12 +462,13 @@ out:
 
 static void hidinput_cleanup_battery(struct hid_device *dev)
 {
-	if (!dev->battery.name)
+	if (!dev->battery)
 		return;
 
-	power_supply_unregister(&dev->battery);
-	kfree(dev->battery.name);
-	dev->battery.name = NULL;
+	power_supply_unregister(dev->battery);
+	kfree(dev->battery->desc->name);
+	kfree(dev->battery->desc);
+	dev->battery = NULL;
 }
 #else  /* !CONFIG_HID_BATTERY_STRENGTH */
 static bool hidinput_setup_battery(struct hid_device *dev, unsigned report_type,
diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
index 16fc6a1..65007ec 100644
--- a/drivers/hid/hid-sony.c
+++ b/drivers/hid/hid-sony.c
@@ -815,7 +815,8 @@ struct sony_sc {
 	struct led_classdev *leds[MAX_LEDS];
 	unsigned long quirks;
 	struct work_struct state_worker;
-	struct power_supply battery;
+	struct power_supply *battery;
+	struct power_supply_desc battery_desc;
 	int device_id;
 	__u8 *output_report_dmabuf;
 
@@ -1660,7 +1661,7 @@ static int sony_battery_get_property(struct power_supply *psy,
 				     enum power_supply_property psp,
 				     union power_supply_propval *val)
 {
-	struct sony_sc *sc = container_of(psy, struct sony_sc, battery);
+	struct sony_sc *sc = power_supply_get_drvdata(psy);
 	unsigned long flags;
 	int ret = 0;
 	u8 battery_charging, battery_capacity, cable_state;
@@ -1699,6 +1700,7 @@ static int sony_battery_get_property(struct power_supply *psy,
 
 static int sony_battery_probe(struct sony_sc *sc)
 {
+	struct power_supply_config psy_cfg = { .drv_data = sc, };
 	struct hid_device *hdev = sc->hdev;
 	int ret;
 
@@ -1708,39 +1710,42 @@ static int sony_battery_probe(struct sony_sc *sc)
 	 */
 	sc->battery_capacity = 100;
 
-	sc->battery.properties = sony_battery_props;
-	sc->battery.num_properties = ARRAY_SIZE(sony_battery_props);
-	sc->battery.get_property = sony_battery_get_property;
-	sc->battery.type = POWER_SUPPLY_TYPE_BATTERY;
-	sc->battery.use_for_apm = 0;
-	sc->battery.name = kasprintf(GFP_KERNEL, "sony_controller_battery_%pMR",
-				     sc->mac_address);
-	if (!sc->battery.name)
+	sc->battery_desc.properties = sony_battery_props;
+	sc->battery_desc.num_properties = ARRAY_SIZE(sony_battery_props);
+	sc->battery_desc.get_property = sony_battery_get_property;
+	sc->battery_desc.type = POWER_SUPPLY_TYPE_BATTERY;
+	sc->battery_desc.use_for_apm = 0;
+	sc->battery_desc.name = kasprintf(GFP_KERNEL,
+					  "sony_controller_battery_%pMR",
+					  sc->mac_address);
+	if (!sc->battery_desc.name)
 		return -ENOMEM;
 
-	ret = power_supply_register(&hdev->dev, &sc->battery, NULL);
-	if (ret) {
+	sc->battery = power_supply_register(&hdev->dev, &sc->battery_desc,
+					    &psy_cfg);
+	if (IS_ERR(sc->battery)) {
+		ret = PTR_ERR(sc->battery);
 		hid_err(hdev, "Unable to register battery device\n");
 		goto err_free;
 	}
 
-	power_supply_powers(&sc->battery, &hdev->dev);
+	power_supply_powers(sc->battery, &hdev->dev);
 	return 0;
 
 err_free:
-	kfree(sc->battery.name);
-	sc->battery.name = NULL;
+	kfree(sc->battery_desc.name);
+	sc->battery_desc.name = NULL;
 	return ret;
 }
 
 static void sony_battery_remove(struct sony_sc *sc)
 {
-	if (!sc->battery.name)
+	if (!sc->battery_desc.name)
 		return;
 
-	power_supply_unregister(&sc->battery);
-	kfree(sc->battery.name);
-	sc->battery.name = NULL;
+	power_supply_unregister(sc->battery);
+	kfree(sc->battery_desc.name);
+	sc->battery_desc.name = NULL;
 }
 
 /*
diff --git a/drivers/hid/hid-wiimote-modules.c b/drivers/hid/hid-wiimote-modules.c
index 91cb00a..05e23c4 100644
--- a/drivers/hid/hid-wiimote-modules.c
+++ b/drivers/hid/hid-wiimote-modules.c
@@ -203,8 +203,7 @@ static int wiimod_battery_get_property(struct power_supply *psy,
 				       enum power_supply_property psp,
 				       union power_supply_propval *val)
 {
-	struct wiimote_data *wdata = container_of(psy, struct wiimote_data,
-						  battery);
+	struct wiimote_data *wdata = power_supply_get_drvdata(psy);
 	int ret = 0, state;
 	unsigned long flags;
 
@@ -238,42 +237,46 @@ static int wiimod_battery_get_property(struct power_supply *psy,
 static int wiimod_battery_probe(const struct wiimod_ops *ops,
 				struct wiimote_data *wdata)
 {
+	struct power_supply_config psy_cfg = { .drv_data = wdata, };
 	int ret;
 
-	wdata->battery.properties = wiimod_battery_props;
-	wdata->battery.num_properties = ARRAY_SIZE(wiimod_battery_props);
-	wdata->battery.get_property = wiimod_battery_get_property;
-	wdata->battery.type = POWER_SUPPLY_TYPE_BATTERY;
-	wdata->battery.use_for_apm = 0;
-	wdata->battery.name = kasprintf(GFP_KERNEL, "wiimote_battery_%s",
-					wdata->hdev->uniq);
-	if (!wdata->battery.name)
+	wdata->battery_desc.properties = wiimod_battery_props;
+	wdata->battery_desc.num_properties = ARRAY_SIZE(wiimod_battery_props);
+	wdata->battery_desc.get_property = wiimod_battery_get_property;
+	wdata->battery_desc.type = POWER_SUPPLY_TYPE_BATTERY;
+	wdata->battery_desc.use_for_apm = 0;
+	wdata->battery_desc.name = kasprintf(GFP_KERNEL, "wiimote_battery_%s",
+					     wdata->hdev->uniq);
+	if (!wdata->battery_desc.name)
 		return -ENOMEM;
 
-	ret = power_supply_register(&wdata->hdev->dev, &wdata->battery, NULL);
-	if (ret) {
+	wdata->battery = power_supply_register(&wdata->hdev->dev,
+					       &wdata->battery_desc,
+					       &psy_cfg);
+	if (IS_ERR(wdata->battery)) {
 		hid_err(wdata->hdev, "cannot register battery device\n");
+		ret = PTR_ERR(wdata->battery);
 		goto err_free;
 	}
 
-	power_supply_powers(&wdata->battery, &wdata->hdev->dev);
+	power_supply_powers(wdata->battery, &wdata->hdev->dev);
 	return 0;
 
 err_free:
-	kfree(wdata->battery.name);
-	wdata->battery.name = NULL;
+	kfree(wdata->battery_desc.name);
+	wdata->battery_desc.name = NULL;
 	return ret;
 }
 
 static void wiimod_battery_remove(const struct wiimod_ops *ops,
 				  struct wiimote_data *wdata)
 {
-	if (!wdata->battery.name)
+	if (!wdata->battery_desc.name)
 		return;
 
-	power_supply_unregister(&wdata->battery);
-	kfree(wdata->battery.name);
-	wdata->battery.name = NULL;
+	power_supply_unregister(wdata->battery);
+	kfree(wdata->battery_desc.name);
+	wdata->battery_desc.name = NULL;
 }
 
 static const struct wiimod_ops wiimod_battery = {
diff --git a/drivers/hid/hid-wiimote.h b/drivers/hid/hid-wiimote.h
index 10934aa..875694d 100644
--- a/drivers/hid/hid-wiimote.h
+++ b/drivers/hid/hid-wiimote.h
@@ -147,7 +147,8 @@ struct wiimote_data {
 	struct led_classdev *leds[4];
 	struct input_dev *accel;
 	struct input_dev *ir;
-	struct power_supply battery;
+	struct power_supply *battery;
+	struct power_supply_desc battery_desc;
 	struct input_dev *mp;
 	struct timer_list timer;
 	struct wiimote_debug *debug;
diff --git a/drivers/hid/wacom.h b/drivers/hid/wacom.h
index 7db4328..0d0d0dd 100644
--- a/drivers/hid/wacom.h
+++ b/drivers/hid/wacom.h
@@ -119,8 +119,10 @@ struct wacom {
 		u8 img_lum;   /* OLED matrix display brightness */
 	} led;
 	bool led_initialized;
-	struct power_supply battery;
-	struct power_supply ac;
+	struct power_supply *battery;
+	struct power_supply *ac;
+	struct power_supply_desc battery_desc;
+	struct power_supply_desc ac_desc;
 };
 
 static inline void wacom_schedule_work(struct wacom_wac *wacom_wac)
@@ -133,7 +135,7 @@ static inline void wacom_notify_battery(struct wacom_wac *wacom_wac)
 {
 	struct wacom *wacom = container_of(wacom_wac, struct wacom, wacom_wac);
 
-	power_supply_changed(&wacom->battery);
+	power_supply_changed(wacom->battery);
 }
 
 extern const struct hid_device_id wacom_ids[];
diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 148949c0..ba9af47 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -944,7 +944,7 @@ static int wacom_battery_get_property(struct power_supply *psy,
 				      enum power_supply_property psp,
 				      union power_supply_propval *val)
 {
-	struct wacom *wacom = container_of(psy, struct wacom, battery);
+	struct wacom *wacom = power_supply_get_drvdata(psy);
 	int ret = 0;
 
 	switch (psp) {
@@ -976,7 +976,7 @@ static int wacom_ac_get_property(struct power_supply *psy,
 				enum power_supply_property psp,
 				union power_supply_propval *val)
 {
-	struct wacom *wacom = container_of(psy, struct wacom, ac);
+	struct wacom *wacom = power_supply_get_drvdata(psy);
 	int ret = 0;
 
 	switch (psp) {
@@ -998,43 +998,46 @@ static int wacom_ac_get_property(struct power_supply *psy,
 static int wacom_initialize_battery(struct wacom *wacom)
 {
 	static atomic_t battery_no = ATOMIC_INIT(0);
-	int error;
+	struct power_supply_config psy_cfg = { .drv_data = wacom, };
 	unsigned long n;
 
 	if (wacom->wacom_wac.features.quirks & WACOM_QUIRK_BATTERY) {
+		struct power_supply_desc *bat_desc = &wacom->battery_desc;
+		struct power_supply_desc *ac_desc = &wacom->ac_desc;
 		n = atomic_inc_return(&battery_no) - 1;
 
-		wacom->battery.properties = wacom_battery_props;
-		wacom->battery.num_properties = ARRAY_SIZE(wacom_battery_props);
-		wacom->battery.get_property = wacom_battery_get_property;
+		bat_desc->properties = wacom_battery_props;
+		bat_desc->num_properties = ARRAY_SIZE(wacom_battery_props);
+		bat_desc->get_property = wacom_battery_get_property;
 		sprintf(wacom->wacom_wac.bat_name, "wacom_battery_%ld", n);
-		wacom->battery.name = wacom->wacom_wac.bat_name;
-		wacom->battery.type = POWER_SUPPLY_TYPE_BATTERY;
-		wacom->battery.use_for_apm = 0;
+		bat_desc->name = wacom->wacom_wac.bat_name;
+		bat_desc->type = POWER_SUPPLY_TYPE_BATTERY;
+		bat_desc->use_for_apm = 0;
 
-		wacom->ac.properties = wacom_ac_props;
-		wacom->ac.num_properties = ARRAY_SIZE(wacom_ac_props);
-		wacom->ac.get_property = wacom_ac_get_property;
+		ac_desc->properties = wacom_ac_props;
+		ac_desc->num_properties = ARRAY_SIZE(wacom_ac_props);
+		ac_desc->get_property = wacom_ac_get_property;
 		sprintf(wacom->wacom_wac.ac_name, "wacom_ac_%ld", n);
-		wacom->ac.name = wacom->wacom_wac.ac_name;
-		wacom->ac.type = POWER_SUPPLY_TYPE_MAINS;
-		wacom->ac.use_for_apm = 0;
-
-		error = power_supply_register(&wacom->hdev->dev,
-					      &wacom->battery, NULL);
-		if (error)
-			return error;
-
-		power_supply_powers(&wacom->battery, &wacom->hdev->dev);
-
-		error = power_supply_register(&wacom->hdev->dev, &wacom->ac,
-					      NULL);
-		if (error) {
-			power_supply_unregister(&wacom->battery);
-			return error;
+		ac_desc->name = wacom->wacom_wac.ac_name;
+		ac_desc->type = POWER_SUPPLY_TYPE_MAINS;
+		ac_desc->use_for_apm = 0;
+
+		wacom->battery = power_supply_register(&wacom->hdev->dev,
+					      &wacom->battery_desc, &psy_cfg);
+		if (IS_ERR(wacom->battery))
+			return PTR_ERR(wacom->battery);
+
+		power_supply_powers(wacom->battery, &wacom->hdev->dev);
+
+		wacom->ac = power_supply_register(&wacom->hdev->dev,
+						  &wacom->ac_desc,
+						  &psy_cfg);
+		if (IS_ERR(wacom->ac)) {
+			power_supply_unregister(wacom->battery);
+			return PTR_ERR(wacom->ac);
 		}
 
-		power_supply_powers(&wacom->ac, &wacom->hdev->dev);
+		power_supply_powers(wacom->ac, &wacom->hdev->dev);
 	}
 
 	return 0;
@@ -1043,11 +1046,11 @@ static int wacom_initialize_battery(struct wacom *wacom)
 static void wacom_destroy_battery(struct wacom *wacom)
 {
 	if ((wacom->wacom_wac.features.quirks & WACOM_QUIRK_BATTERY) &&
-	     wacom->battery.dev) {
-		power_supply_unregister(&wacom->battery);
-		wacom->battery.dev = NULL;
-		power_supply_unregister(&wacom->ac);
-		wacom->ac.dev = NULL;
+	     wacom->battery) {
+		power_supply_unregister(wacom->battery);
+		wacom->battery = NULL;
+		power_supply_unregister(wacom->ac);
+		wacom->ac = NULL;
 	}
 }