Re: [PATCH] ALSA: hda: Fix NULL pointer dereference in snd_hda_ctl_add()

[Takashi Iwai <tiwai@suse.de>]

On Thu, 14 May 2026 15:22:45 +0200,
Quan Sun wrote:
> 
> snd_hda_ctl_add() dereferences kctl->id.subdevice without checking
> whether kctl is NULL. Multiple callers in sound/hda/codecs/ca0132.c
> pass the return value of snd_ctl_new1() directly to snd_hda_ctl_add()
> without a NULL check:
> 
>     return snd_hda_ctl_add(codec, nid, snd_ctl_new1(&knew, codec));
> 
> snd_ctl_new1() returns NULL when the underlying snd_ctl_new() fails
> on memory allocation (kzalloc_flex),which can occur under memory
> pressure or via fault injection.
> 
> Add a NULL check at the entry of snd_hda_ctl_add(), matching the
> pattern already used by snd_ctl_add_replace() at the same call
> path (sound/core/control.c:515). Return -EINVAL to let callers
> handle the error gracefully.
> 
> Fixes: 44f0c9782cc6 ("ALSA: hda/ca0132: Add tuning controls")
> Signed-off-by: Quan Sun <2022090917019@std.uestc.edu.cn>

Applied now.  Thanks.


Takashi