The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 76959aff14a0012ad6b984ec7686d163deccdc16 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024100730-uneatable-grill-4244@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..
Possible dependencies:
76959aff14a0 ("ACPI: battery: Fix possible crash when unregistering a battery hook") 86309cbed261 ("ACPI: battery: Simplify battery hook locking")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 76959aff14a0012ad6b984ec7686d163deccdc16 Mon Sep 17 00:00:00 2001 From: Armin Wolf W_Armin@gmx.de Date: Tue, 1 Oct 2024 23:28:34 +0200 Subject: [PATCH] ACPI: battery: Fix possible crash when unregistering a battery hook
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
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index dda59ee5a11e..1c45ff6dbb83 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -715,7 +715,7 @@ static void battery_hook_unregister_unlocked(struct acpi_battery_hook *hook) if (!hook->remove_battery(battery->bat, hook)) power_supply_changed(battery->bat); } - list_del(&hook->list); + list_del_init(&hook->list);
pr_info("extension unregistered: %s\n", hook->name); } @@ -723,7 +723,14 @@ 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); @@ -733,7 +740,6 @@ 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