Commit b837a9f5 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: hda: realtek: Fix race at concurrent COEF updates 



The COEF access is done with two steps: setting the index then read or
write the data.  When multiple COEF accesses are performed
concurrently, the index and data might be paired unexpectedly.
In most cases, this isn't a big problem as the COEF setup is done at
the initialization, but some dynamic changes like the mute LED may hit
such a race.

For avoiding the racy COEF accesses, this patch introduces a new
mutex coef_mutex to alc_spec, and wrap the COEF accessing functions
with it.

Reported-by: default avatarAlexander Sergeyev <sergeev917@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220111195229.a77wrpjclqwrx4bx@localhost.localdomain
Link: https://lore.kernel.org/r/20220131075738.24323-1-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 0444f827

sound/pci/hda/patch_realtek.c

+50 −11
Original line number Diff line number Diff line
@@ -98,6 +98,7 @@ struct alc_spec { 
	unsigned int gpio_mic_led_mask;

	struct alc_coef_led mute_led_coef;

	struct alc_coef_led mic_led_coef;

	struct mutex coef_mutex;



	hda_nid_t headset_mic_pin;

	hda_nid_t headphone_mic_pin;
@@ -137,7 +138,7 @@ struct alc_spec { 
 * COEF access helper functions

 */



static int alc_read_coefex_idx(struct hda_codec *codec, hda_nid_t nid,

static int __alc_read_coefex_idx(struct hda_codec *codec, hda_nid_t nid,

				 unsigned int coef_idx)

{

	unsigned int val;
@@ -147,30 +148,63 @@ static int alc_read_coefex_idx(struct hda_codec *codec, hda_nid_t nid, 
	return val;

}



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);

	val = __alc_read_coefex_idx(codec, nid, coef_idx);

	mutex_unlock(&spec->coef_mutex);

	return val;

}



#define alc_read_coef_idx(codec, coef_idx) \

	alc_read_coefex_idx(codec, 0x20, coef_idx)



static void alc_write_coefex_idx(struct hda_codec *codec, hda_nid_t nid,

static void __alc_write_coefex_idx(struct hda_codec *codec, hda_nid_t nid,

				   unsigned int coef_idx, unsigned int coef_val)

{

	snd_hda_codec_write(codec, nid, 0, AC_VERB_SET_COEF_INDEX, coef_idx);

	snd_hda_codec_write(codec, nid, 0, AC_VERB_SET_PROC_COEF, coef_val);

}



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);

	__alc_write_coefex_idx(codec, nid, coef_idx, coef_val);

	mutex_unlock(&spec->coef_mutex);

}



#define alc_write_coef_idx(codec, coef_idx, coef_val) \

	alc_write_coefex_idx(codec, 0x20, coef_idx, coef_val)



static void alc_update_coefex_idx(struct hda_codec *codec, hda_nid_t nid,

static void __alc_update_coefex_idx(struct hda_codec *codec, hda_nid_t nid,

				    unsigned int coef_idx, unsigned int mask,

				    unsigned int bits_set)

{

	unsigned int val = alc_read_coefex_idx(codec, nid, coef_idx);

	unsigned int val = __alc_read_coefex_idx(codec, nid, coef_idx);



	if (val != -1)

		alc_write_coefex_idx(codec, nid, coef_idx,

		__alc_write_coefex_idx(codec, nid, coef_idx,

				       (val & ~mask) | bits_set);

}



static void alc_update_coefex_idx(struct hda_codec *codec, hda_nid_t nid,

				  unsigned int coef_idx, unsigned int mask,

				  unsigned int bits_set)

{

	struct alc_spec *spec = codec->spec;



	mutex_lock(&spec->coef_mutex);

	__alc_update_coefex_idx(codec, nid, coef_idx, mask, bits_set);

	mutex_unlock(&spec->coef_mutex);

}



#define alc_update_coef_idx(codec, coef_idx, mask, bits_set)	\

	alc_update_coefex_idx(codec, 0x20, coef_idx, mask, bits_set)
@@ -201,13 +235,17 @@ 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);

	for (; fw->nid; fw++) {

		if (fw->mask == (unsigned short)-1)

			alc_write_coefex_idx(codec, fw->nid, fw->idx, fw->val);

			__alc_write_coefex_idx(codec, fw->nid, fw->idx, fw->val);

		else

			alc_update_coefex_idx(codec, fw->nid, fw->idx,

			__alc_update_coefex_idx(codec, fw->nid, fw->idx,

						fw->mask, fw->val);

	}

	mutex_unlock(&spec->coef_mutex);

}



/*
@@ -1153,6 +1191,7 @@ static int alc_alloc_spec(struct hda_codec *codec, hda_nid_t mixer_nid) 
	codec->spdif_status_reset = 1;

	codec->forced_resume = 1;

	codec->patch_ops = alc_patch_ops;

	mutex_init(&spec->coef_mutex);



	err = alc_codec_rename_from_preset(codec);

	if (err < 0) {