[PATCH 5.16 140/227] ALSA: hda/realtek: Fix deadlock by COEF mutex

Greg Kroah-Hartman
2022-02-21T09:59:25Z

From: Takashi Iwai <tiwai@suse.de>

commit 2a845837e3d0ddaed493b4c5c4643d7f0542804d upstream.

The recently introduced coef_mutex for Realtek codec seems causing a
deadlock when the relevant code is invoked from the power-off state;
then the HD-audio core tries to power-up internally, and this kicks
off the codec runtime PM code that tries to take the same coef_mutex.

In order to avoid the deadlock, do the temporary power up/down around
the coef_mutex acquisition and release. This assures that the
power-up sequence runs before the mutex, hence no re-entrance will
happen.

Fixes: b837a9f5ab3b ("ALSA: hda: realtek: Fix race at concurrent COEF updates")
Reported-and-tested-by: Julian Wollrath <jwollrath@web.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220214132838.4db10fca@schienar
Link: https://lore.kernel.org/r/20220214130410.21230-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/pci/hda/patch_realtek.c | 39 ++++++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 15 deletions(-)

--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -133,6 +133,22 @@ struct alc_spec {
* COEF access helper functions
*/

+static void coef_mutex_lock(struct hda_codec *codec)
+{
+ struct alc_spec *spec = codec->spec;
+
+ snd_hda_power_up_pm(codec);
+ mutex_lock(&spec->coef_mutex);
+}
+
+static void coef_mutex_unlock(struct hda_codec *codec)
+{
+ struct alc_spec *spec = codec->spec;
+
+ mutex_unlock(&spec->coef_mutex);
+ snd_hda_power_down_pm(codec);
+}
+
static int __alc_read_coefex_idx(struct hda_codec *codec, hda_nid_t nid,
unsigned int coef_idx)
{
@@ -146,12 +162,11 @@ static int __alc_read_coefex_idx(struct
static int alc_read_coefex_idx(struct hda_codec *codec, hda_nid_t nid,
unsigned int coef_idx)
{
- struct alc_spec *spec = codec->spec;
unsigned int val;

- mutex_lock(&spec->coef_mutex);
+ coef_mutex_lock(codec);
val = __alc_read_coefex_idx(codec, nid, coef_idx);
- mutex_unlock(&spec->coef_mutex);
+ coef_mutex_unlock(codec);
return val;
}

@@ -168,11 +183,9 @@ static void __alc_write_coefex_idx(struc
static void alc_write_coefex_idx(struct hda_codec *codec, hda_nid_t nid,
unsigned int coef_idx, unsigned int coef_val)
{
- struct alc_spec *spec = codec->spec;
-
- mutex_lock(&spec->coef_mutex);
+ coef_mutex_lock(codec);
__alc_write_coefex_idx(codec, nid, coef_idx, coef_val);
- mutex_unlock(&spec->coef_mutex);
+ coef_mutex_unlock(codec);
}

#define alc_write_coef_idx(codec, coef_idx, coef_val) \
@@ -193,11 +206,9 @@ static void alc_update_coefex_idx(struct
unsigned int coef_idx, unsigned int mask,
unsigned int bits_set)
{
- struct alc_spec *spec = codec->spec;
-
- mutex_lock(&spec->coef_mutex);
+ coef_mutex_lock(codec);
__alc_update_coefex_idx(codec, nid, coef_idx, mask, bits_set);
- mutex_unlock(&spec->coef_mutex);
+ coef_mutex_unlock(codec);
}

#define alc_update_coef_idx(codec, coef_idx, mask, bits_set) \
@@ -230,9 +241,7 @@ struct coef_fw {
static void alc_process_coef_fw(struct hda_codec *codec,
const struct coef_fw *fw)
{
- struct alc_spec *spec = codec->spec;
-
- mutex_lock(&spec->coef_mutex);
+ coef_mutex_lock(codec);
for (; fw->nid; fw++) {
if (fw->mask == (unsigned short)-1)
__alc_write_coefex_idx(codec, fw->nid, fw->idx, fw->val);
@@ -240,7 +249,7 @@ static void alc_process_coef_fw(struct h
__alc_update_coefex_idx(codec, fw->nid, fw->idx,
fw->mask, fw->val);
}
- mutex_unlock(&spec->coef_mutex);
+ coef_mutex_unlock(codec);
}

/*