ACPI / Battery: Resolve the race condition in the sysfs_remove_battery()

[firefly-linux-kernel-4.4.55.git] / drivers / acpi / battery.c

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 4ba339d0ea1920ef9bf4d16dc8d190cc27c3dda6..40bf01d42cc3b52937e07d5a941ea3d6505b2c87 100644 (file)
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -573,11 +573,16 @@ static int sysfs_add_battery(struct acpi_battery *battery)
 
 static void sysfs_remove_battery(struct acpi_battery *battery)
 {
-       if (!battery->bat.dev)
+       mutex_lock(&battery->lock);
+       if (!battery->bat.dev) {
+               mutex_unlock(&battery->lock);
                return;
+       }
+
        device_remove_file(battery->bat.dev, &alarm_attr);
        power_supply_unregister(&battery->bat);
        battery->bat.dev = NULL;
+       mutex_unlock(&battery->lock);
 }
 
 /*