On Fri, Apr 17, 2020 at 02:33:10PM +0300, Tomi Valkeinen wrote:
> led_bl does not lock 'led_access' when calling led_sysfs_disable and
> led_sysfs_enable, causing the below WARN. Add the locking.
>
> WARNING: CPU: 0 PID: 223 at drivers/leds/led-core.c:353 led_sysfs_disable+0x4c/0x5c
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
I did wonder if it might be better to provide self-locking API from the
LED sub-sys but it looks like elsewhere led_sysfs_disable() is
frequently paired with led_trigger_set() (and both under the same
lock)...
Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
> ---
> drivers/video/backlight/led_bl.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c
> index c46ecdfe8b0a..63693c4f0883 100644
> --- a/drivers/video/backlight/led_bl.c
> +++ b/drivers/video/backlight/led_bl.c
> @@ -216,8 +216,11 @@ static int led_bl_probe(struct platform_device *pdev)
> return PTR_ERR(priv->bl_dev);
> }
>
> - for (i = 0; i < priv->nb_leds; i++)
> + for (i = 0; i < priv->nb_leds; i++) {
> + mutex_lock(&priv->leds[i]->led_access);
> led_sysfs_disable(priv->leds[i]);
> + mutex_unlock(&priv->leds[i]->led_access);
> + }
>
> backlight_update_status(priv->bl_dev);
>
> @@ -233,8 +236,11 @@ static int led_bl_remove(struct platform_device *pdev)
> backlight_device_unregister(bl);
>
> led_bl_power_off(priv);
> - for (i = 0; i < priv->nb_leds; i++)
> + for (i = 0; i < priv->nb_leds; i++) {
> + mutex_lock(&priv->leds[i]->led_access);
> led_sysfs_enable(priv->leds[i]);
> + mutex_unlock(&priv->leds[i]->led_access);
> + }
>
> return 0;
> }
> --
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
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