Commit 0c0fe9e6 authored by Kai Vehmanen's avatar Kai Vehmanen Committed by Takashi Iwai
Browse files

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: 5398e94f ALSA: hda - Add DP-MST support for NVIDIA codecs
Signed-off-by: default avatarKai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20191129143756.23941-1-kai.vehmanen@linux.intel.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 336820c4

sound/pci/hda/patch_hdmi.c

+11 −11
Original line number Diff line number Diff line
@@ -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 */

CRA Git | Maintained and supported by SUSTech CRA and CCSE