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