[PATCH 4.1 54/78] ALSA: hda: fix possible NULL dereference

Greg Kroah-Hartman
2015-09-11T22:51:05Z

From: Markus Osterhoff <linux-kernel@k-raum.org>

commit c7e69ae6b4ff49edf50180c0a32f3dd9d7967e31 upstream.

After a for-loop was replaced by list_for_each_entry, see
Commit bbbc7e8502c9 ("ALSA: hda - Allocate hda_pcm objects dynamically"),
Commit 751e2216899c ("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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/pci/hda/hda_codec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -3259,7 +3259,7 @@ static int add_std_chmaps(struct hda_cod
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;