[PATCH v4 2/2] ASoC: codecs: nau8360: Fix AB-BA deadlock in mux update
From: Neo Chang <hidden>
Date: 2026-09-09 02:59:56
Also in:
alsa-devel, linux-sound
Subsystem:
sound, sound - soc layer / dynamic audio power management (asoc), the rest · Maintainers:
Jaroslav Kysela, Takashi Iwai, Liam Girdwood, Mark Brown, Linus Torvalds
nau8360_dac_mux_put_enum() acquires nau8360->lock before the DAPM mutex, causing an AB-BA lock inversion. This deadlocks with concurrent stream startups or mixer updates, which acquire locks in the reverse order. Fix this by replacing nau8360->lock with the DAPM mutex to protect pre-checks, releasing it before calling snd_soc_dapm_put_enum_double(). Reported-by: Sashiko AI <sashiko-bot@kernel.org> Link: https://sashiko.dev/#/patchset/20260908030342.222655-1-YLCHANG2@nuvoton.com?part=1 Signed-off-by: Neo Chang <redacted> --- sound/soc/codecs/nau8360.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/sound/soc/codecs/nau8360.c b/sound/soc/codecs/nau8360.c
index 277aa982c341..7f83c737e8af 100644
--- a/sound/soc/codecs/nau8360.c
+++ b/sound/soc/codecs/nau8360.c@@ -689,6 +689,8 @@ static void nau8360_dsp_switch(struct snd_soc_component *component, bool enable) struct regmap *regmap = nau8360->regmap; int value = NAU8360_PEQ_BAND_8; + mutex_lock(&nau8360->lock); + /* If DSP is enabled, unstall HW3 engine and DSP, loading DSP firmware, * and configure PEQ after dsp reset. */
@@ -702,6 +704,7 @@ static void nau8360_dsp_switch(struct snd_soc_component *component, bool enable) regmap_update_bits(regmap, NAU8360_R9D_PEQ_CTL, NAU8360_PEQ_BAND_MASK, value << NAU8360_PEQ_BAND_SFT); + mutex_unlock(&nau8360->lock); } static int nau8360_dac_mux_put_enum(struct snd_kcontrol *kcontrol,
@@ -714,27 +717,26 @@ static int nau8360_dac_mux_put_enum(struct snd_kcontrol *kcontrol, unsigned int *item = ucontrol->value.enumerated.item; int ret = 0; + snd_soc_dapm_mutex_lock(dapm); if (snd_soc_dapm_get_bias_level(dapm) > SND_SOC_BIAS_STANDBY) { dev_warn_ratelimited(nau8360->dev, "changing path is not allowed during playback"); + snd_soc_dapm_mutex_unlock(dapm); return ret; } if (item[0] == NAU8360_DAC_SRC_DSP && !nau8360->load_fw_done) { dev_warn_ratelimited(nau8360->dev, "Cannot enable DSP: Firmware not ready or disabled\n"); + snd_soc_dapm_mutex_unlock(dapm); return -EBUSY; } - - mutex_lock(&nau8360->lock); + snd_soc_dapm_mutex_unlock(dapm); ret = snd_soc_dapm_put_enum_double(kcontrol, ucontrol); if (ret <= 0) - goto unlock; + return ret; nau8360_dsp_switch(component, snd_soc_enum_item_to_val(e, item[0])); -unlock: - mutex_unlock(&nau8360->lock); - return ret; }
--
2.25.1