On Tue, Aug 18, 2026 at 10:20:20PM +0800, Runyu Xiao wrote:

gb_lights_light_register() registers each channel before initializing light->channels[i].lock. Channel registration exposes the LED class device and its brightness callback, which later takes this mutex. A concurrent brightness update can therefore hit an uninitialized lock.

Initialize the channel mutex before registering the channel so the callback always sees a valid lock.

Fixes: cc43368a3cde ("greybus: lights: Control runtime pm suspend/resume on AP side") Cc: stable@vger.kernel.org Signed-off-by: Runyu Xiao runyu.xiao@seu.edu.cn

---

drivers/staging/greybus/light.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c index 38c233a706c4..056ef6b0276e 100644 --- a/drivers/staging/greybus/light.c +++ b/drivers/staging/greybus/light.c @@ -1043,11 +1043,11 @@ static int gb_lights_light_register(struct gb_light *light) * found. */ for (i = 0; i < light->channels_count; i++) {

• mutex_init(&light->channels[i].lock);
  

• ret = gb_lights_channel_register(&light->channels[i]); if (ret < 0) return ret;

• mutex_init(&light->channels[i].lock);
  

  }

light->ready = true;

How was this found and tested?

thanks,

greg k-h