Re: [PATCH] backlight: lm3630a: Cancel delayed work before destroying workqueue

[Daniel Thompson <danielt@kernel.org>]

On Fri, Oct 02, 2026 at 11:04:39PM -0400, Myeonghun Pak wrote:
> The interrupt handler queues delayed work to read the interrupt status.
> After free_irq() stops the producer, this work can still be waiting on its
> timer. destroy_workqueue() cannot drain delayed work that has not yet been
> queued by its timer, so the timer can outlive both the workqueue and the
> devm-allocated chip containing the work.
>
> Cancel the delayed work synchronously after freeing the IRQ and before
> destroying the workqueue. This also waits for any running status read to
> finish before the chip's resources are released.
>
> This issue was identified during our ongoing static-analysis research
> while reviewing kernel code.
>
> Fixes: 0c2a665a648e ("backlight: add Backlight driver for lm3630 chip")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>

Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>


Daniel.