Re: [PATCH] hwmon: (gigabyte_waterforce) Mark status report as received under a spinlock

[Guenter Roeck <linux@roeck-us.net>]

On Tue, Dec 19, 2023 at 03:36:19PM +0100, Aleksa Savic wrote:
> Through hidraw, userspace can cause a status report to be sent
> from the device. The parsing in waterforce_raw_event() may happen in
> parallel to a waterforce_get_status() call (which resets the completion
> for tracking the report) if it's running on a different CPU where
> bottom half interrupts are not disabled.
> 
> Add a spinlock around the complete_all() call in waterforce_raw_event()
> to prevent race issues.
> 
> Fixes: d5939a793693 ("hwmon: Add driver for Gigabyte AORUS Waterforce AIO coolers")
> Signed-off-by: Aleksa Savic <savicaleksa83@gmail.com>
> ---
> Does the above make sense? The raw event parsing is a softirq AFAIK and
> presumably could run on a different CPU in parallel to a waterforce_get_status()
> call.
> 
> Appreciate thoughts on this.

I think it does. Applied.

Thanks,
Guenter

> ---
>  drivers/hwmon/gigabyte_waterforce.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/hwmon/gigabyte_waterforce.c b/drivers/hwmon/gigabyte_waterforce.c
> index 1799377fc2f1..85e523775714 100644
> --- a/drivers/hwmon/gigabyte_waterforce.c
> +++ b/drivers/hwmon/gigabyte_waterforce.c
> @@ -276,8 +276,10 @@ static int waterforce_raw_event(struct hid_device *hdev, struct hid_report *repo
>  	priv->duty_input[0] = data[WATERFORCE_FAN_DUTY];
>  	priv->duty_input[1] = data[WATERFORCE_PUMP_DUTY];
>  
> +	spin_lock(&priv->status_report_request_lock);
>  	if (!completion_done(&priv->status_report_received))
>  		complete_all(&priv->status_report_received);
> +	spin_unlock(&priv->status_report_request_lock);
>  
>  	priv->updated = jiffies;
>