From 9c921c22a7f33397a6774d7fa076db9b6a0fd669 Mon Sep 17 00:00:00 2001
From: Lan Tianyu <tianyu.lan@intel.com>
Date: Thu, 30 Jun 2011 11:34:12 +0800
Subject: ACPI / Battery: Resolve the race condition in the
sysfs_remove_battery()
Use battery->lock in sysfs_remove_battery() to make
checking, removing, and clearing bat.dev atomic.
This is necessary because sysfs_remove_battery() may
be invoked concurrently from different paths.
https://bugzilla.kernel.org/show_bug.cgi?id=35642
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
drivers/acpi/battery.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 4ba339d0ea1..40bf01d42cc 100644
--- 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);
}
/*
--
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