On Thu, 19 Sep 2024 08:33:32 +0200
Armin Wolf <W_Armin@xxxxxx> wrote:
> If the battery hook encounters a unsupported battery, it will
> return an error. This in turn will cause the battery driver to
> automatically unregister the battery hook.
>
> However as soon as the driver itself attempts to unregister the
> already unregistered battery hook, a crash occurs due to a
> corrupted linked list.
>
> Fix this by simply ignoring unsupported batteries.
>
> Tested on a Dell Inspiron 3505.
>
> Fixes: ab58016c68cc ("platform/x86:dell-laptop: Add knobs to change battery charge settings")
> Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
> ---
> I CCed the maintainers of the ACPI battery driver since i believe
> that this patch highlights a general issue inside the battery hook
> mechanism.
>
> This is because the same crash will be triggered should for example
> device_add_groups() fail.
>
> Any ideas on how to solve this problem?
> ---
Hm, I see that when battery_hook_register() has the add_battery hook fail,
then __battery_hook_unregister() calls the remove_battery hook. Does
something like the following fix it?
(note: not any kind of final patch, just a test.)
---
drivers/platform/x86/dell/dell-laptop.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/platform/x86/dell/dell-laptop.c b/drivers/platform/x86/dell/dell-laptop.c
index a9de19799f01..c7b92b2f7ed2 100644
--- a/drivers/platform/x86/dell/dell-laptop.c
+++ b/drivers/platform/x86/dell/dell-laptop.c
@@ -2390,21 +2390,29 @@ static struct attribute *dell_battery_attrs[] = {
NULL,
};
ATTRIBUTE_GROUPS(dell_battery);
+static bool bgroup_registered = false;
static int dell_battery_add(struct power_supply *battery,
struct acpi_battery_hook *hook)
{
+ int err;
+
/* this currently only supports the primary battery */
if (strcmp(battery->desc->name, "BAT0") != 0)
return -ENODEV;
- return device_add_groups(&battery->dev, dell_battery_groups);
+ err = device_add_groups(&battery->dev, dell_battery_groups);
+ if (!err)
+ bgroup_registered = true;
+
+ return err;
}
static int dell_battery_remove(struct power_supply *battery,
struct acpi_battery_hook *hook)
{
- device_remove_groups(&battery->dev, dell_battery_groups);
+ if (bgroup_registered)
+ device_remove_groups(&battery->dev, dell_battery_groups);
return 0;
}
--
2.39.5
--
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