Re: [PATCH 3/6] ASoC: meson: add audin FIFO driver

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Calling a sleeping function from atomic and hardirq contexts.
--

commit 44499e80857bb0a40e090af263ae83ec007e6008
Author: Valerio Setti <vsetti@baylibre.com>

ASoC: meson: add audin FIFO driver

Add support for the frontend DAI of the capture interface which is in
charge of receiving decoded data from "audin-formatter-i2s" and move them
to an internal FIFO before they are block-transferred to RAM.

> diff --git a/sound/soc/meson/audin-fifo.c b/sound/soc/meson/audin-fifo.c
> new file mode 100644
> index 0000000000000..7029bd6a464ab
> --- /dev/null
> +++ b/sound/soc/meson/audin-fifo.c

[ ... ]

> +static unsigned int audin_fifo_pos(struct snd_soc_component *component,
> +				   struct snd_pcm_runtime *runtime)
> +{
> +	unsigned int ptr = snd_soc_component_read(component, AUDIN_FIFO_PTR);

[Severity: High]
Can this call into a sleeping function from atomic and hardirq contexts?

The audin_fifo_pos() function calls snd_soc_component_read(), which
explicitly acquires a sleeping mutex. However, this is called by
audin_fifo_timer_cb() (an hrtimer callback executing in hardirq context)
and by audin_fifo_component_pointer() (an ALSA PCM pointer callback that
executes while holding a spinlock).

Acquiring a sleeping lock from either of these contexts can trigger a
kernel panic during audio capture.

> +
> +	return ptr - lower_32_bits(runtime->dma_addr);
> +}

[ ... ]

> +static enum hrtimer_restart audin_fifo_timer_cb(struct hrtimer *timer)
> +{
> +	struct audin_fifo_dai_data *data =
> +		container_of(timer, struct audin_fifo_dai_data, polling_timer);
> +	struct snd_pcm_runtime *runtime = data->substream->runtime;
> +	unsigned int curr_pos, delta, sleep_time;
> +
> +	if (!READ_ONCE(data->running))
> +		return HRTIMER_NORESTART;
> +
> +	curr_pos = audin_fifo_pos(data->component, runtime);

[ ... ]

> +static snd_pcm_uframes_t
> +audin_fifo_component_pointer(struct snd_soc_component *component,
> +			     struct snd_pcm_substream *substream)
> +{
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +
> +	return bytes_to_frames(runtime, audin_fifo_pos(component, runtime));
> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260912-audin-v1-0-7fbefe928711@baylibre.com?part=3

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