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ALSA: hda: hdmi - fix kernel oops caused by invalid PCM idx

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Add additional check in hdmi_find_pcm_slot() to not return
a pcm index that points to unallocated pcm. This could happen
if codec driver is set up in codec->mst_no_extra_pcms mode.
On some platforms, this leads to a kernel oops in snd_ctl_notify(),
called via update_eld().

BugLink: https://github.com/thesofproject/linux/issues/1536
Fixes: 5398e94fb7 ALSA: hda - Add DP-MST support for NVIDIA codecs
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20191129143756.23941-1-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Kai Vehmanen 2019-11-29 16:37:55 +02:00 committed by Takashi Iwai
parent 336820c437
commit 0c0fe9e6b9
1 changed files with 10 additions and 10 deletions
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20
sound/pci/hda/patch_hdmi.c
View file

@ -1335,24 +1335,24 @@ static int hdmi_find_pcm_slot(struct hdmi_spec *spec,
int i;
/*
* generic_hdmi_build_pcms() allocates (num_nids + dev_num - 1)
* number of pcms.
* generic_hdmi_build_pcms() may allocate extra PCMs on some
* platforms (with maximum of 'num_nids + dev_num - 1')
*
* The per_pin of pin_nid_idx=n and dev_id=m prefers to get pcm-n
* if m==0. This guarantees that dynamic pcm assignments are compatible
* with the legacy static per_pin-pmc assignment that existed in the
* with the legacy static per_pin-pcm assignment that existed in the
* days before DP-MST.
*
* per_pin of m!=0 prefers to get pcm=(num_nids + (m - 1)).
*/
if (per_pin->dev_id == 0 &&
!test_bit(per_pin->pin_nid_idx, &spec->pcm_bitmap))
return per_pin->pin_nid_idx;
if (per_pin->dev_id != 0 &&
!(test_bit(spec->num_nids + (per_pin->dev_id - 1),
&spec->pcm_bitmap))) {
return spec->num_nids + (per_pin->dev_id - 1);
if (per_pin->dev_id == 0) {
if (!test_bit(per_pin->pin_nid_idx, &spec->pcm_bitmap))
return per_pin->pin_nid_idx;
} else {
i = spec->num_nids + (per_pin->dev_id - 1);
if (i < spec->pcm_used && !(test_bit(i, &spec->pcm_bitmap)))
return i;
}
/* have a second try; check the area over num_nids */