4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Armin Wolf <W_Armin@xxxxxx>
[ 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>
---
drivers/acpi/battery.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index b741ed87ab3db..46aa0e5e6f8b6 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -724,7 +724,7 @@ 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);
}
@@ -732,7 +732,14 @@ 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);
@@ -742,7 +749,6 @@ 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
--
2.43.0
