Re: [PATCH] ALSA: core: Validate compress device numbers without dynamic minors

[Takashi Iwai]

On Wed, 25 Mar 2026 06:24:04 +0100,
Cássio Gabriel wrote:
> 
> Without CONFIG_SND_DYNAMIC_MINORS, ALSA reserves only two fixed minors
> for compress devices on each card: comprD0 and comprD1.
> 
> snd_find_free_minor() currently computes the compress minor as
> type + dev without validating dev first, so device numbers greater than
> 1 spill into the HWDEP minor range instead of failing registration.
> 
> ASoC passes rtd->id to snd_compress_new(), so this can happen on real
> non-dynamic-minor builds.
> 
> Add a dedicated fixed-minor check for SNDRV_DEVICE_TYPE_COMPRESS in
> snd_find_free_minor() and reject out-of-range device numbers with
> -EINVAL before constructing the minor.
> 
> Also remove the stale TODO in compress_offload.c that still claims
> multiple compress nodes are missing.
> 
> Fixes: 3eafc959b32f ("ALSA: core: add support for compressed devices")
> Signed-off-by: Cássio Gabriel <cassiogabrielcontato@xxxxxxxxx>

Applied to for-next branch now.  Thanks.


Takashi