Re: [PATCH RESEND] ALSA: hda/cs35l41: Fix firmware load work teardown

[Charles Keepax]

On Mon, May 11, 2026 at 01:29:34AM -0300, Cássio Gabriel wrote:
> cs35l41_hda creates ALSA controls whose private data points at the
> cs35l41_hda object. The firmware load control can also queue
> fw_load_work.
> 
> Those controls are not removed on component unbind, and device remove
> only cancels fw_load_work through cs35l41_remove_dsp(). That helper is
> skipped when halo_initialized is false. With firmware_autostart
> disabled, a firmware load can be requested before the DSP has been
> initialized. If the component or device is removed before the queued
> work runs, the worker can run after teardown and dereference driver
> state that is no longer valid.
> 
> Track the created controls and remove them on unbind so no new control
> callback can reach the driver data or queue more work. Then cancel
> fw_load_work to drain any request that was already queued. Also cancel
> the work unconditionally during device remove before runtime PM teardown.
> 
> Fixes: 47ceabd99a28 ("ALSA: hda: cs35l41: Support Firmware switching and reloading")
> Fixes: 4c870513fbb0 ("ALSA: hda: cs35l41: Add read-only ALSA control for forced mute")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Cássio Gabriel <cassiogabrielcontato@xxxxxxxxx>
> ---
>  static bool cs35l41_dsm_supported(acpi_handle handle, unsigned int commands)
> @@ -1522,6 +1550,10 @@ static void cs35l41_hda_unbind(struct device *dev, struct device *master, void *
>  		device_link_remove(&cs35l41->codec->core.dev, cs35l41->dev);
>  		unlock_system_sleep(sleep_flags);
>  		memset(comp, 0, sizeof(*comp));
> +
> +		cs35l41_remove_controls(cs35l41);
> +		cancel_work_sync(&cs35l41->fw_load_work);
> +		cs35l41->codec = NULL;

Hmm... are we sure the controls are actually still accessible
from user-space here? Feels like generally it would make more
sense to make all the cards controls inaccessible before we start
tearing the card down as a core feature.

Adding the cancel works looks very sensible.

@Stefan, could you also please have a look.

Thanks,
Charles