Re: [PATCH] ALSA: hwdep: fix NULL dereference on error path

[Guangshuo Li]

Hi Takashi,

Thanks for the correction.

I overlooked the NULL check in put_device(), so the reported NULL
dereference on this error path is not valid.

Sorry for the noise. Please disregard this patch.

Thanks,
Guangshuo

Takashi Iwai <tiwai@xxxxxxx> 于2026年4月13日周一 13:22写道：
>
> On Sun, 12 Apr 2026 19:45:29 +0200,
> Guangshuo Li wrote:
> >
> > snd_hwdep_new() allocates a hwdep instance first and then allocates
> > hwdep->dev via snd_device_alloc().
> >
> > When snd_device_alloc() fails, hwdep->dev remains NULL, because
> > snd_device_alloc() clears *dev_p before attempting to allocate the
> > device object. The error path then calls snd_hwdep_free(), which
> > unconditionally invokes put_device(hwdep->dev).
> >
> > This may lead to a NULL pointer dereference in put_device().
>
> put_device() has a NULL check by itself, so it's safe to pass NULL
> there.
>
>
> thanks,
>
> Takashi