[alsa-devel] Loopback interface: suspend/resume leads to a kernel crash

[Takashi Iwai]

At Sat, 2 Feb 2013 16:05:54 +0100,
El boulangero wrote:
> 
> Hi Takashi, thanks for your quick reply.
> 
> 
> > Which kernel are you using?  Some races in aloop driver have been
> > fixed in 3.7 kernel.
> 
> I tried different kernel versions, including:
>  + official debian kernel (3.2.0-4)
>  + liquorix debian kernel (3.7.0-4)
>  + upstream kernel from kernel.org (git repository, 3.8.0-rc6 at the moment)
> 
> The bug is present in every version.
> 
> 
> > If the problem is still seen on 3.6 kernel, try the patch below.
> > Let me know if it fixes the problem.
> 
> I applied this patch to the upstream kernel, and it fixes the problem.
> Thanks a lot !

OK, I applied the patch now.


thanks,

Takashi

> 
> Regards,
> Arnaud.
> 
> 
> 2013/2/1 Takashi Iwai <tiwai at suse.de>:
> > At Fri, 01 Feb 2013 15:48:53 +0100,
> > Takashi Iwai wrote:
> >>
> >> At Thu, 31 Jan 2013 21:09:13 +0100,
> >> El boulangero wrote:
> >> >
> >> > Hi,
> >> >
> >> > I use the loopback device all the time. It works pretty good, except
> >> > when I suspend my computer to RAM. On resume, I've got a kernel call
> >> > trace.
> >>
> >> Which kernel are you using?  Some races in aloop driver have been
> >> fixed in 3.7 kernel.
> >
> > If the problem is still seen on 3.6 kernel, try the patch below.
> > Let me know if it fixes the problem.
> >
> >
> > Takashi
> >
> > ---
> > diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
> > index 3d82232..64d5347 100644
> > --- a/sound/drivers/aloop.c
> > +++ b/sound/drivers/aloop.c
> > @@ -286,12 +286,14 @@ static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
> >                         loopback_active_notify(dpcm);
> >                 break;
> >         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> > +       case SNDRV_PCM_TRIGGER_SUSPEND:
> >                 spin_lock(&cable->lock);
> >                 cable->pause |= stream;
> >                 loopback_timer_stop(dpcm);
> >                 spin_unlock(&cable->lock);
> >                 break;
> >         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> > +       case SNDRV_PCM_TRIGGER_RESUME:
> >                 spin_lock(&cable->lock);
> >                 dpcm->last_jiffies = jiffies;
> >                 cable->pause &= ~stream;
> > @@ -563,7 +565,8 @@ static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
> >  static struct snd_pcm_hardware loopback_pcm_hardware =
> >  {
> >         .info =         (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
> > -                        SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE),
> > +                        SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
> > +                        SNDRV_PCM_INFO_RESUME),
> >         .formats =      (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
> >                          SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
> >                          SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
>