kernel/linux.git/drivers/acpi/battery.c, branch v6.6.131

ACPI: battery: Add synchronization between interface updates

2025-10-19T14:31:00+00:00

[ Upstream commit 399dbcadc01ebf0035f325eaa8c264f8b5cd0a14 ] 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: 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 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/20250910142653.313360-1-luogf2025@163.com/ Reported-by: GuangFei Luo Tested-by: GuangFei Luo Cc: 6.6+ # 6.6+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

ACPI: battery: Check for error code from devm_mutex_init() call

2025-10-19T14:31:00+00:00

[ 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 Reviewed-by: Thomas Weißschuh Link: https://patch.msgid.link/20241030162754.2110946-1-andriy.shevchenko@linux.intel.com [ rjw: Added 2 empty code lines ] Signed-off-by: Rafael J. Wysocki Stable-dep-of: 399dbcadc01e ("ACPI: battery: Add synchronization between interface updates") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

ACPI: battery: initialize mutexes through devm_ APIs

2025-10-19T14:30:59+00:00

[ Upstream commit 0710c1ce50455ed0db91bffa0eebbaa4f69b1773 ] Simplify the cleanup logic a bit. Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20240904-acpi-battery-cleanups-v1-3-a3bf74f22d40@weissschuh.net Signed-off-by: Rafael J. Wysocki Stable-dep-of: 399dbcadc01e ("ACPI: battery: Add synchronization between interface updates") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

ACPI: battery: allocate driver data through devm_ APIs

2025-10-19T14:30:59+00:00

[ Upstream commit 909dfc60692331e1599d5e28a8f08a611f353aef ] Simplify the cleanup logic a bit. Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20240904-acpi-battery-cleanups-v1-2-a3bf74f22d40@weissschuh.net Signed-off-by: Rafael J. Wysocki Stable-dep-of: 399dbcadc01e ("ACPI: battery: Add synchronization between interface updates") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

Revert "ACPI: battery: negate current when discharging"

2025-07-17T16:35:14+00:00

commit de1675de39aa945bad5937d1fde4df3682670639 upstream. Revert commit 234f71555019 ("ACPI: battery: negate current when discharging") breaks not one but several userspace implementations of battery monitoring: Steam and MangoHud. Perhaps it breaks more, but those are the two that have been tested. Reported-by: Matthew Schwartz Closes: https://lore.kernel.org/linux-acpi/87C1B2AF-D430-4568-B620-14B941A8ABA4@linux.dev/ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

ACPI: battery: negate current when discharging

2025-06-27T10:08:52+00:00

[ Upstream commit 234f71555019d308c6bc6f98c78c5551cb8cd56a ] The ACPI specification requires that battery rate is always positive, but the kernel ABI for POWER_SUPPLY_PROP_CURRENT_NOW (Documentation/ABI/testing/sysfs-class-power) specifies that it should be negative when a battery is discharging. When reporting CURRENT_NOW, massage the value to match the documented ABI. This only changes the sign of `current_now` and not `power_now` because documentation doesn't describe any particular meaning for `power_now` so leaving `power_now` unchanged is less likely to confuse userspace unnecessarily, whereas becoming consistent with the documented ABI is worth potentially confusing clients that read `current_now`. Signed-off-by: Peter Marheine Link: https://patch.msgid.link/20250508024146.1436129-1-pmarheine@chromium.org Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: battery: Fix possible crash when unregistering a battery hook

2024-10-10T09:58:06+00:00

[ Upstream commit 76959aff14a0012ad6b984ec7686d163deccdc16 ] When a battery hook returns an error when adding a new battery, then the battery hook is automatically unregistered. However the battery hook provider cannot know that, so it will later call battery_hook_unregister() on the already unregistered battery hook, resulting in a crash. Fix this by using the list head to mark already unregistered battery hooks as already being unregistered so that they can be ignored by battery_hook_unregister(). Fixes: fa93854f7a7e ("battery: Add the battery hooking API") Signed-off-by: Armin Wolf Link: https://patch.msgid.link/20241001212835.341788-3-W_Armin@gmx.de Cc: All applicable Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: battery: Simplify battery hook locking

2024-10-10T09:58:06+00:00

[ Upstream commit 86309cbed26139e1caae7629dcca1027d9a28e75 ] Move the conditional locking from __battery_hook_unregister() into battery_hook_unregister() and rename the low-level function to simplify the locking during battery hook removal. Reviewed-by: Ilpo Järvinen Reviewed-by: Pali Rohár Signed-off-by: Armin Wolf Link: https://patch.msgid.link/20241001212835.341788-2-W_Armin@gmx.de Signed-off-by: Rafael J. Wysocki Stable-dep-of: 76959aff14a0 ("ACPI: battery: Fix possible crash when unregistering a battery hook") Signed-off-by: Sasha Levin

ACPI: battery: create alarm sysfs attribute atomically

2024-08-14T11:58:42+00:00

[ Upstream commit a231eed10ed5a290129fda36ad7bcc263c53ff7d ] Let the power supply core register the attribute. This ensures that the attribute is created before the device is announced to userspace, avoid a race condition. Signed-off-by: Thomas Weißschuh Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: battery: Install Notify() handler directly

2023-07-14T16:58:34+00:00

Modify the ACPI battery driver to install its own Notify() handler directly instead of providing an ACPI driver .notify() callback. This will allow the ACPI driver .notify() callback to be eliminated and it will allow the battery driver to be switched over to a platform one in the future. While at it, fix up whitespaces in acpi_battery_remove(). Suggested-by: Rafael J. Wysocki Signed-off-by: Michal Wilczynski [ rjw: Subject and changelog edits, whitespace adjustments ] Signed-off-by: Rafael J. Wysocki