Re: [PATCH v4] ACPI: battery: prevent sysfs_add_battery re-entry on rapid events

On Sat, Sep 13, 2025 at 03:19:25PM +0800, GuangFei Luo wrote:

v4:

• Uses guard(mutex) for battery->sysfs_lock in sysfs_add_battery().
• Since sysfs_add_battery() now handles the battery->bat check with proper locking,the extra if (!battery->bat) check at the call site has become redundant.

v3:

• Modified the earlier approach: since sysfs_add_battery() is invoked from multiple places, the most reliable way is to add the lock inside the function itself.
• sysfs_remove_battery() had a similar race issue in the past, which was fixed by adding a lock as well. Reference: https://lore.kernel.org/all/9c921c22a7f33397a6774d7fa076db9b6a0fd669

.1312318300.git.len.brown@intel.com/

v2:

• Fix missing mutex_unlock in acpi_battery_update() (Reported-by: kernel test robot)

v1: When removing and reinserting the laptop battery, ACPI can trigger two notifications in quick succession:

Again, all of this goes below the --- line, not above it.