FAILED: patch "[PATCH] ACPI: battery: Add synchronization between interface updates" failed to apply to 6.12-stable tree

PATCH New [email protected] 2 participants 5 messages Oct 16, 2025

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Stable branch ACPI

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2025-10-16 08:39 UTC #0 lore raw

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 399dbcadc01ebf0035f325eaa8c264f8b5cd0a14
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025101634-factsheet-preplan-069e@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 399dbcadc01ebf0035f325eaa8c264f8b5cd0a14 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <[email protected]>
Date: Sun, 28 Sep 2025 12:18:29 +0200
Subject: [PATCH] ACPI: battery: Add synchronization between interface updates

There is no synchronization between different code paths in the ACPI battery driver that update its sysfs interface or its power supply class device interface. In some cases this results to functional failures due to race conditions.

One example of this is when two ACPI notifications:

- ACPI_BATTERY_NOTIFY_STATUS (0x80)
- ACPI_BATTERY_NOTIFY_INFO (0x81)

are triggered (by the platform firmware) in a row with a little delay in between after removing and reinserting a laptop battery. Both notifications cause acpi_battery_update() to be called and if the delay between them is sufficiently small, sysfs_add_battery() can be re-entered before battery->bat is set which leads to a duplicate sysfs entry error:

sysfs: cannot create duplicate filename '/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0A:00/power_supply/BAT1'

 CPU: 1 UID: 0 PID: 185 Comm: kworker/1:4 Kdump: loaded Not tainted 6.12.38+deb13-amd64 #1  Debian 6.12.38-1
 Hardware name: Gateway          NV44             /SJV40-MV        , BIOS V1.3121 04/08/2009
 Workqueue: kacpi_notify acpi_os_execute_deferred
 Call Trace:
  <TASK>
  dump_stack_lvl+0x5d/0x80
  sysfs_warn_dup.cold+0x17/0x23
  sysfs_create_dir_ns+0xce/0xe0
  kobject_add_internal+0xba/0x250
  kobject_add+0x96/0xc0
  ? get_device_parent+0xde/0x1e0
  device_add+0xe2/0x870
  __power_supply_register.part.0+0x20f/0x3f0
  ? wake_up_q+0x4e/0x90
  sysfs_add_battery+0xa4/0x1d0 [battery]
  acpi_battery_update+0x19e/0x290 [battery]
  acpi_battery_notify+0x50/0x120 [battery]
  acpi_ev_notify_dispatch+0x49/0x70
  acpi_os_execute_deferred+0x1a/0x30
  process_one_work+0x177/0x330
  worker_thread+0x251/0x390
  ? __pfx_worker_thread+0x10/0x10
  kthread+0xd2/0x100
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x34/0x50
  ? __pfx_kthread+0x10/0x10
  ret_from_fork_asm+0x1a/0x30
  </TASK>
 kobject: kobject_add_internal failed for BAT1 with -EEXIST, don't try to register things with the same name in the same directory.

There are also other scenarios in which analogous issues may occur.

Address this by using a common lock in all of the code paths leading to updates of driver interfaces: ACPI Notify () handler, system resume callback and post-resume notification, device addition and removal.

This new lock replaces sysfs_lock that has been used only in sysfs_remove_battery() which now is going to be always called under the new lock, so it doesn't need any internal locking any more.

Fixes 10666251554c ("ACPI: battery: Install Notify() handler directly")

Closes https://lore.kernel.org/linux-acpi/[email protected]/ open here

Reported-by GuangFei Luo <[email protected]>

Tested-by GuangFei Luo <[email protected]>

Cc 6.6+ <[email protected]> # 6.6+

Signed-off-by Rafael J. Wysocki <[email protected]>

drivers/acpi/battery.c +29 ~~-14~~

index 6905b56bf3e4..67b76492c839 100644
@@ -92,7 +92,7 @@ enum {
 
 struct acpi_battery {
 	struct mutex lock;
-	struct mutex sysfs_lock;
+	struct mutex update_lock;
 	struct power_supply *bat;
 	struct power_supply_desc bat_desc;
 	struct acpi_device *device;

@@ -904,15 +904,12 @@ static int sysfs_add_battery(struct acpi_battery *battery)
 
 static void sysfs_remove_battery(struct acpi_battery *battery)
 {
-	mutex_lock(&battery->sysfs_lock);
-	if (!battery->bat) {
-		mutex_unlock(&battery->sysfs_lock);
+	if (!battery->bat)
 		return;
-	}
+
 	battery_hook_remove_battery(battery);
 	power_supply_unregister(battery->bat);
 	battery->bat = NULL;
-	mutex_unlock(&battery->sysfs_lock);
 }
 
 static void find_battery(const struct dmi_header *dm, void *private)

@@ -1072,6 +1069,9 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
 
 	if (!battery)
 		return;
+
+	guard(mutex)(&battery->update_lock);
+
 	old = battery->bat;
 	/*
 	 * On Acer Aspire V5-573G notifications are sometimes triggered too

@@ -1094,21 +1094,22 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
 }
 
 static int battery_notify(struct notifier_block *nb,
-			       unsigned long mode, void *_unused)
+			  unsigned long mode, void *_unused)
 {
 	struct acpi_battery *battery = container_of(nb, struct acpi_battery,
 						    pm_nb);
-	int result;
 
-	switch (mode) {
-	case PM_POST_HIBERNATION:
-	case PM_POST_SUSPEND:
+	if (mode == PM_POST_SUSPEND || mode == PM_POST_HIBERNATION) {
+		guard(mutex)(&battery->update_lock);
+
 		if (!acpi_battery_present(battery))
 			return 0;
 
 		if (battery->bat) {
 			acpi_battery_refresh(battery);
 		} else {
+			int result;
+
 			result = acpi_battery_get_info(battery);
 			if (result)
 				return result;

@@ -1120,7 +1121,6 @@ static int battery_notify(struct notifier_block *nb,
 
 		acpi_battery_init_alarm(battery);
 		acpi_battery_get_state(battery);
-		break;
 	}
 
 	return 0;

@@ -1198,6 +1198,8 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
 {
 	int retry, ret;
 
+	guard(mutex)(&battery->update_lock);
+
 	for (retry = 5; retry; retry--) {
 		ret = acpi_battery_update(battery, false);
 		if (!ret)

@@ -1208,6 +1210,13 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
 	return ret;
 }
 
+static void sysfs_battery_cleanup(struct acpi_battery *battery)
+{
+	guard(mutex)(&battery->update_lock);
+
+	sysfs_remove_battery(battery);
+}
+
 static int acpi_battery_add(struct acpi_device *device)
 {
 	int result = 0;

@@ -1230,7 +1239,7 @@ static int acpi_battery_add(struct acpi_device *device)
 	if (result)
 		return result;
 
-	result = devm_mutex_init(&device->dev, &battery->sysfs_lock);
+	result = devm_mutex_init(&device->dev, &battery->update_lock);
 	if (result)
 		return result;

@@ -1262,7 +1271,7 @@ static int acpi_battery_add(struct acpi_device *device)
 	device_init_wakeup(&device->dev, 0);
 	unregister_pm_notifier(&battery->pm_nb);
 fail:
-	sysfs_remove_battery(battery);
+	sysfs_battery_cleanup(battery);
 
 	return result;
 }

@@ -1281,6 +1290,9 @@ static void acpi_battery_remove(struct acpi_device *device)
 
 	device_init_wakeup(&device->dev, 0);
 	unregister_pm_notifier(&battery->pm_nb);
+
+	guard(mutex)(&battery->update_lock);
+
 	sysfs_remove_battery(battery);
 }

@@ -1297,6 +1309,9 @@ static int acpi_battery_resume(struct device *dev)
 		return -EINVAL;
 
 	battery->update_time = 0;
+
+	guard(mutex)(&battery->update_lock);
+
 	acpi_battery_update(battery, true);
 	return 0;
 }

Sasha Levin

maintainer

2025-10-16 13:34 UTC #1 lore raw

PATCH 1/4 ACPI: battery: allocate driver data through devm_ APIs

From: Thomas Weißschuh <[email protected]>

[ Upstream commit 909dfc60692331e1599d5e28a8f08a611f353aef ]

Simplify the cleanup logic a bit.

Signed-off-by Thomas Weißschuh <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Rafael J. Wysocki <[email protected]>

Stable-dep-of: 399dbcadc01e ("ACPI: battery: Add synchronization between interface updates")

Signed-off-by Sasha Levin <[email protected]>

---
 drivers/acpi/battery.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

drivers/acpi/battery.c +1 -3

index 65fa3444367a1..c6e29e377b9ca 100644
@@ -1218,7 +1218,7 @@ static int acpi_battery_add(struct acpi_device *device)
 	if (device->dep_unmet)
 		return -EPROBE_DEFER;
 
-	battery = kzalloc(sizeof(struct acpi_battery), GFP_KERNEL);
+	battery = devm_kzalloc(&device->dev, sizeof(*battery), GFP_KERNEL);
 	if (!battery)
 		return -ENOMEM;
 	battery->device = device;

@@ -1256,7 +1256,6 @@ static int acpi_battery_add(struct acpi_device *device)
 	sysfs_remove_battery(battery);
 	mutex_destroy(&battery->lock);
 	mutex_destroy(&battery->sysfs_lock);
-	kfree(battery);
 
 	return result;
 }

@@ -1279,7 +1278,6 @@ static void acpi_battery_remove(struct acpi_device *device)
 
 	mutex_destroy(&battery->lock);
 	mutex_destroy(&battery->sysfs_lock);
-	kfree(battery);
 }
 
 #ifdef CONFIG_PM_SLEEP

Signature · 1 line

2.51.0

Sasha Levin

maintainer

2025-10-16 13:34 UTC #2 lore raw

PATCH 2/4 ACPI: battery: initialize mutexes through devm_ APIs

From: Thomas Weißschuh <[email protected]>

[ Upstream commit 0710c1ce50455ed0db91bffa0eebbaa4f69b1773 ]

Simplify the cleanup logic a bit.

Signed-off-by Thomas Weißschuh <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Rafael J. Wysocki <[email protected]>

Stable-dep-of: 399dbcadc01e ("ACPI: battery: Add synchronization between interface updates")

Signed-off-by Sasha Levin <[email protected]>

---
 drivers/acpi/battery.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

drivers/acpi/battery.c +2 -7

index c6e29e377b9ca..1a10eeddedac1 100644
@@ -1225,8 +1225,8 @@ static int acpi_battery_add(struct acpi_device *device)
 	strscpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
 	strscpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
 	device->driver_data = battery;
-	mutex_init(&battery->lock);
-	mutex_init(&battery->sysfs_lock);
+	devm_mutex_init(&device->dev, &battery->lock);
+	devm_mutex_init(&device->dev, &battery->sysfs_lock);
 	if (acpi_has_method(battery->device->handle, "_BIX"))
 		set_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);

@@ -1254,8 +1254,6 @@ static int acpi_battery_add(struct acpi_device *device)
 	unregister_pm_notifier(&battery->pm_nb);
 fail:
 	sysfs_remove_battery(battery);
-	mutex_destroy(&battery->lock);
-	mutex_destroy(&battery->sysfs_lock);
 
 	return result;
 }

@@ -1275,9 +1273,6 @@ static void acpi_battery_remove(struct acpi_device *device)
 	device_init_wakeup(&device->dev, 0);
 	unregister_pm_notifier(&battery->pm_nb);
 	sysfs_remove_battery(battery);
-
-	mutex_destroy(&battery->lock);
-	mutex_destroy(&battery->sysfs_lock);
 }
 
 #ifdef CONFIG_PM_SLEEP

Signature · 1 line

2.51.0

Sasha Levin

maintainer

2025-10-16 13:34 UTC #3 lore raw

PATCH 3/4 ACPI: battery: Check for error code from devm_mutex_init() call

In reply to Sasha Levin

From: Andy Shevchenko <[email protected]>

[ Upstream commit 815daedc318b2f9f1b956d0631377619a0d69d96 ]

Even if it's not critical, the avoidance of checking the error code from devm_mutex_init() call today diminishes the point of using devm variant of it. Tomorrow it may even leak something. Add the missed check.

Fixes 0710c1ce5045 ("ACPI: battery: initialize mutexes through devm_ APIs")

Signed-off-by Andy Shevchenko <[email protected]>

Reviewed-by Thomas Weißschuh <[email protected]>

Link https://patch.msgid.link/[email protected] open here

[ rjw: Added 2 empty code lines ]

Signed-off-by Rafael J. Wysocki <[email protected]>

Stable-dep-of: 399dbcadc01e ("ACPI: battery: Add synchronization between interface updates")

Signed-off-by Sasha Levin <[email protected]>

---
 drivers/acpi/battery.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

drivers/acpi/battery.c +8 -2

index 1a10eeddedac1..8d3e44f0caf44 100644
@@ -1225,8 +1225,14 @@ static int acpi_battery_add(struct acpi_device *device)
 	strscpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
 	strscpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
 	device->driver_data = battery;
-	devm_mutex_init(&device->dev, &battery->lock);
-	devm_mutex_init(&device->dev, &battery->sysfs_lock);
+	result = devm_mutex_init(&device->dev, &battery->lock);
+	if (result)
+		return result;
+
+	result = devm_mutex_init(&device->dev, &battery->sysfs_lock);
+	if (result)
+		return result;
+
 	if (acpi_has_method(battery->device->handle, "_BIX"))
 		set_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);

Signature · 1 line

2.51.0

Sasha Levin

maintainer

2025-10-16 13:34 UTC #4 lore raw

PATCH 4/4 ACPI: battery: Add synchronization between interface updates

In reply to Sasha Levin

From: "Rafael J. Wysocki" <[email protected]>

[ Upstream commit 399dbcadc01ebf0035f325eaa8c264f8b5cd0a14 ]

One example of this is when two ACPI notifications:

- ACPI_BATTERY_NOTIFY_STATUS (0x80)
- ACPI_BATTERY_NOTIFY_INFO (0x81)

sysfs: cannot create duplicate filename '/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0A:00/power_supply/BAT1'

 CPU: 1 UID: 0 PID: 185 Comm: kworker/1:4 Kdump: loaded Not tainted 6.12.38+deb13-amd64 #1  Debian 6.12.38-1
 Hardware name: Gateway          NV44             /SJV40-MV        , BIOS V1.3121 04/08/2009
 Workqueue: kacpi_notify acpi_os_execute_deferred
 Call Trace:
  <TASK>
  dump_stack_lvl+0x5d/0x80
  sysfs_warn_dup.cold+0x17/0x23
  sysfs_create_dir_ns+0xce/0xe0
  kobject_add_internal+0xba/0x250
  kobject_add+0x96/0xc0
  ? get_device_parent+0xde/0x1e0
  device_add+0xe2/0x870
  __power_supply_register.part.0+0x20f/0x3f0
  ? wake_up_q+0x4e/0x90
  sysfs_add_battery+0xa4/0x1d0 [battery]
  acpi_battery_update+0x19e/0x290 [battery]
  acpi_battery_notify+0x50/0x120 [battery]
  acpi_ev_notify_dispatch+0x49/0x70
  acpi_os_execute_deferred+0x1a/0x30
  process_one_work+0x177/0x330
  worker_thread+0x251/0x390
  ? __pfx_worker_thread+0x10/0x10
  kthread+0xd2/0x100
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x34/0x50
  ? __pfx_kthread+0x10/0x10
  ret_from_fork_asm+0x1a/0x30
  </TASK>
 kobject: kobject_add_internal failed for BAT1 with -EEXIST, don't try to register things with the same name in the same directory.

There are also other scenarios in which analogous issues may occur.

This new lock replaces sysfs_lock that has been used only in sysfs_remove_battery() which now is going to be always called under the new lock, so it doesn't need any internal locking any more.

Fixes 10666251554c ("ACPI: battery: Install Notify() handler directly")

Closes https://lore.kernel.org/linux-acpi/[email protected]/ open here

Reported-by GuangFei Luo <[email protected]>

Tested-by GuangFei Luo <[email protected]>

Cc 6.6+ <[email protected]> # 6.6+

Signed-off-by Rafael J. Wysocki <[email protected]>

Signed-off-by Sasha Levin <[email protected]>

---
 drivers/acpi/battery.c | 43 ++++++++++++++++++++++++++++--------------
 1 file changed, 29 insertions(+), 14 deletions(-)

drivers/acpi/battery.c +29 ~~-14~~

index 8d3e44f0caf44..11c7e35fafa25 100644
@@ -92,7 +92,7 @@ enum {
 
 struct acpi_battery {
 	struct mutex lock;
-	struct mutex sysfs_lock;
+	struct mutex update_lock;
 	struct power_supply *bat;
 	struct power_supply_desc bat_desc;
 	struct acpi_device *device;

@@ -903,15 +903,12 @@ static int sysfs_add_battery(struct acpi_battery *battery)
 
 static void sysfs_remove_battery(struct acpi_battery *battery)
 {
-	mutex_lock(&battery->sysfs_lock);
-	if (!battery->bat) {
-		mutex_unlock(&battery->sysfs_lock);
+	if (!battery->bat)
 		return;
-	}
+
 	battery_hook_remove_battery(battery);
 	power_supply_unregister(battery->bat);
 	battery->bat = NULL;
-	mutex_unlock(&battery->sysfs_lock);
 }
 
 static void find_battery(const struct dmi_header *dm, void *private)

@@ -1071,6 +1068,9 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
 
 	if (!battery)
 		return;
+
+	guard(mutex)(&battery->update_lock);
+
 	old = battery->bat;
 	/*
 	 * On Acer Aspire V5-573G notifications are sometimes triggered too

@@ -1093,21 +1093,22 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
 }
 
 static int battery_notify(struct notifier_block *nb,
-			       unsigned long mode, void *_unused)
+			  unsigned long mode, void *_unused)
 {
 	struct acpi_battery *battery = container_of(nb, struct acpi_battery,
 						    pm_nb);
-	int result;
 
-	switch (mode) {
-	case PM_POST_HIBERNATION:
-	case PM_POST_SUSPEND:
+	if (mode == PM_POST_SUSPEND || mode == PM_POST_HIBERNATION) {
+		guard(mutex)(&battery->update_lock);
+
 		if (!acpi_battery_present(battery))
 			return 0;
 
 		if (battery->bat) {
 			acpi_battery_refresh(battery);
 		} else {
+			int result;
+
 			result = acpi_battery_get_info(battery);
 			if (result)
 				return result;

@@ -1119,7 +1120,6 @@ static int battery_notify(struct notifier_block *nb,
 
 		acpi_battery_init_alarm(battery);
 		acpi_battery_get_state(battery);
-		break;
 	}
 
 	return 0;

@@ -1197,6 +1197,8 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
 {
 	int retry, ret;
 
+	guard(mutex)(&battery->update_lock);
+
 	for (retry = 5; retry; retry--) {
 		ret = acpi_battery_update(battery, false);
 		if (!ret)

@@ -1207,6 +1209,13 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
 	return ret;
 }
 
+static void sysfs_battery_cleanup(struct acpi_battery *battery)
+{
+	guard(mutex)(&battery->update_lock);
+
+	sysfs_remove_battery(battery);
+}
+
 static int acpi_battery_add(struct acpi_device *device)
 {
 	int result = 0;

@@ -1229,7 +1238,7 @@ static int acpi_battery_add(struct acpi_device *device)
 	if (result)
 		return result;
 
-	result = devm_mutex_init(&device->dev, &battery->sysfs_lock);
+	result = devm_mutex_init(&device->dev, &battery->update_lock);
 	if (result)
 		return result;

@@ -1259,7 +1268,7 @@ static int acpi_battery_add(struct acpi_device *device)
 	device_init_wakeup(&device->dev, 0);
 	unregister_pm_notifier(&battery->pm_nb);
 fail:
-	sysfs_remove_battery(battery);
+	sysfs_battery_cleanup(battery);
 
 	return result;
 }

@@ -1278,6 +1287,9 @@ static void acpi_battery_remove(struct acpi_device *device)
 
 	device_init_wakeup(&device->dev, 0);
 	unregister_pm_notifier(&battery->pm_nb);
+
+	guard(mutex)(&battery->update_lock);
+
 	sysfs_remove_battery(battery);
 }

@@ -1295,6 +1307,9 @@ static int acpi_battery_resume(struct device *dev)
 		return -EINVAL;
 
 	battery->update_time = 0;
+
+	guard(mutex)(&battery->update_lock);
+
 	acpi_battery_update(battery, true);
 	return 0;
 }

Signature · 1 line

2.51.0