Multiple calls to dapm_power_widgets() can create a race condition causing power list to be corrupted. Those scenarios can occur in multistream usecases, stream start/stop along with simultaneous update power calls (mixer, mux, dapm_sync, stream_event).

A new 'dapm_mutex' is added to soc_card, which is held while power list is created.

Signed-off-by: Misael Lopez Cruz misael.lopez@ti.com --- include/sound/soc.h | 1 + sound/soc/soc-core.c | 1 + sound/soc/soc-dapm.c | 2 ++ 3 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h index 7e65b01..3dfc608 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -614,6 +614,7 @@ struct snd_soc_card {

struct list_head list; struct mutex mutex; + struct mutex dapm_mutex;

bool instantiated;

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 1dc4b11..583a821 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -3124,6 +3124,7 @@ static int snd_soc_register_card(struct snd_soc_card *card) INIT_LIST_HEAD(&card->list); card->instantiated = 0; mutex_init(&card->mutex); + mutex_init(&card->dapm_mutex);

mutex_lock(&client_mutex); list_add(&card->list, &card_list); diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c index 3d310af..faee456 100644 --- a/sound/soc/soc-dapm.c +++ b/sound/soc/soc-dapm.c @@ -940,6 +940,7 @@ static int dapm_power_widgets(struct snd_soc_dapm_context *dapm, int event) /* Check which widgets we need to power and store them in * lists indicating if they should be powered up or down. */ + mutex_lock(&card->dapm_mutex); list_for_each_entry(w, &dapm->widgets, list) { switch (w->id) { case snd_soc_dapm_pre: @@ -974,6 +975,7 @@ static int dapm_power_widgets(struct snd_soc_dapm_context *dapm, int event) break; } } + mutex_unlock(&card->dapm_mutex);

/* If there are no DAPM widgets then try to figure out power from the * event type.