4.19-stable review patch. If anyone has any objections, please let me know.
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From: Armin Wolf W_Armin@gmx.de
[ 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@gmx.de Link: https://patch.msgid.link/20241001212835.341788-3-W_Armin@gmx.de Cc: All applicable stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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