ALSA: hda - Fix NULL dereference with CONFIG_SND_DYNAMIC_MINORS=n

Without the dynamic minor assignment, HDMI codec may have less PCM
instances than the number of pins, which eventually leads to Oops.

Reported-by: Stratos Karafotis <stratosk@semaphore.gr>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 030ca8652a1cb3b5b8f825d684b69ec1bb2daacc..9f35862768713899cad3ba865bb9d13b3cee796a 100644 (file)
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -1781,6 +1781,9 @@ static int generic_hdmi_build_controls(struct hda_codec *codec)
                struct snd_pcm_chmap *chmap;
                struct snd_kcontrol *kctl;
                int i;
+
+               if (!codec->pcm_info[pin_idx].pcm)
+                       break;
                err = snd_pcm_add_chmap_ctls(codec->pcm_info[pin_idx].pcm,
                                             SNDRV_PCM_STREAM_PLAYBACK,
                                             NULL, 0, pin_idx, &chmap);