Re: ALSA: hda - Fix possible races in HDMI driver - lockup on shutdownwhen radeon.audio=1 after using audacity

[Arthur Marsh]

Takashi Iwai wrote, on 20/01/14 19:22:
> At Sun, 19 Jan 2014 17:32:16 +1030,
> Arthur Marsh wrote:
> > I have had reproducible lock-ups on shut-down (at the shutting down ALSA
> > stage) of my AMD64 machine (Asus M3A78Pro motherboard, BIOS 1701
> > 01/27/2011, CPU AMD Athlon(tm) II X4 640 Processor) running the 64 bit
> > Linux kernel more recent than 3.12 when *both* radeon.audio=1 was set
> > and I had been running audacity 2.0.5. (iommu=noaperture is also set).
> >
> > The problem was reproducible with the stock Debian kernel
> > linux-image-3.13-rc6-amd64 version 3.13~rc6-1~exp1.
> >
> > The machine is using an ATI/AMD 3850HD video card with a DVI cable to a
> > DVI input on my monitor, and the default audio device is the
> > motherboard's on-board audio device:
> >
> > 00:14.2 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] SBx00
> > Azalia (Intel HDA)
> >
> > 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc.
> > [AMD/ATI] RV670 [Radeon HD 3690/3850]
> > 01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] RV670/680
> > HDMI Audio [Radeon HD 3690/3800 Series]
> >
> > $ git bisect bad
> > cbbaa603a03cc46681e24d6b2804b62fde95a2af is the first bad commit
> > commit cbbaa603a03cc46681e24d6b2804b62fde95a2af
> > Author: Takashi Iwai <tiwai@xxxxxxx>
> > Date:   Thu Oct 17 18:03:24 2013 +0200
> >
> >       ALSA: hda - Fix possible races in HDMI driver
> >
> >       Some per_pin fields and ELD contents might be changed dynamically in
> >       multiple ways where the concurrent accesses are still opened in the
> >       current code.  This patch fixes such possible races by using eld->lock
> >       in appropriate places.
> >
> >       Reported-by: Anssi Hannula <anssi.hannula@xxxxxx>
> >       Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> >
> > :040000 040000 0c29281f82a3ebd9a704d481114f9cfcefea07c8
> > d71fd101125cd29a628cb5e66c7ee4f56e28329b M      sound
> >
> > When running audacity from the command line there was the following output:
> >
> > ALSA lib pcm_dsnoop.c:618:(snd_pcm_dsnoop_open) unable to open slave
> > ALSA lib pcm_dmix.c:1022:(snd_pcm_dmix_open) unable to open slave
> > ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
> > ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
> > ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
> > ALSA lib pcm_dmix.c:1022:(snd_pcm_dmix_open) unable to open slave
> > Expression 'stream->playback.pcm' failed in
> > 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611
> > Expression 'stream->playback.pcm' failed in
> > 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611
> > Expression 'stream->playback.pcm' failed in
> > 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611
> >
> > I am happy to supply further information or run further tests to help in
> > isolating the problem and verifying a solution.
>
> Could you build the kernel with lockdep kconfig and see whether it
> reports errors?
>
> Reverting the commit doesn't work cleanly.  Instead, you can try to
> simply comment out all mutex_lock(&per_pin->lock) and
> mutex_unlock(&per_pin->lock) calls in patch_hdmi.c to see whether it's
> a mutex deadlock.
>
>
> thanks,
>
> Takashi

I rebuilt the kernel after commenting out all mutex_lock(&per_pin->lock) 
and mutex_unlock(&per_pin->lock) calls in patch_hdmi.c, and the 
resulting kernel shutdown without hanging.

Regards,

Arthur.
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