This is a note to let you know that I've just added the patch titled
ACPI: battery: Fix possible crash when unregistering a battery hook
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
acpi-battery-fix-possible-crash-when-unregistering-a.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cbee14156b0c677125c14b5efc5db955e5e1b2f5
Author: Armin Wolf <W_Armin@xxxxxx>
Date: Tue Oct 1 23:28:34 2024 +0200
ACPI: battery: Fix possible crash when unregistering a battery hook
[ 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 <W_Armin@xxxxxx>
Link: https://patch.msgid.link/20241001212835.341788-3-W_Armin@xxxxxx
Cc: All applicable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 59d38c6e45d83..5a4e022662417 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -703,7 +703,7 @@ static void battery_hook_unregister_unlocked(struct acpi_battery_hook *hook)
list_for_each_entry(battery, &acpi_battery_list, list) {
hook->remove_battery(battery->bat);
}
- list_del(&hook->list);
+ list_del_init(&hook->list);
pr_info("extension unregistered: %s\n", hook->name);
}
@@ -711,7 +711,14 @@ static void battery_hook_unregister_unlocked(struct acpi_battery_hook *hook)
void battery_hook_unregister(struct acpi_battery_hook *hook)
{
mutex_lock(&hook_mutex);
- battery_hook_unregister_unlocked(hook);
+ /*
+ * Ignore already unregistered battery hooks. This might happen
+ * if a battery hook was previously unloaded due to an error when
+ * adding a new battery.
+ */
+ if (!list_empty(&hook->list))
+ battery_hook_unregister_unlocked(hook);
+
mutex_unlock(&hook_mutex);
}
EXPORT_SYMBOL_GPL(battery_hook_unregister);
@@ -721,7 +728,6 @@ void battery_hook_register(struct acpi_battery_hook *hook)
struct acpi_battery *battery;
mutex_lock(&hook_mutex);
- INIT_LIST_HEAD(&hook->list);
list_add(&hook->list, &battery_hook_list);
/*
* Now that the driver is registered, we need
