ALSA: hda: fix possible NULL dereference

Markus Osterhoff · tiwai · commit c7e69ae6b4ff · 2015-08-24T15:02:03.000+02:00
After a for-loop was replaced by list_for_each_entry, see Commit bbbc7e8 ("ALSA: hda - Allocate hda_pcm objects dynamically"), Commit 751e221 ("ALSA: hda: fix possible null dereference"), a possible NULL pointer dereference has been introduced; this patch adds the NULL check on pcm->pcm, while leaving a potentially superfluous check on pcm itself untouched. Signed-off-by: Markus Osterhoff <linux-kernel@k-raum.org> Cc: <stable@vger.kernel.org> #v4.1+ Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
@@ -3172,7 +3172,7 @@ static int add_std_chmaps(struct hda_codec *codec)
 			struct snd_pcm_chmap *chmap;
 			const struct snd_pcm_chmap_elem *elem;
 
-			if (!pcm || pcm->own_chmap ||
+			if (!pcm || !pcm->pcm || pcm->own_chmap ||
 			    !hinfo->substreams)
 				continue;
 			elem = hinfo->chmap ? hinfo->chmap : snd_pcm_std_chmaps;
