On Mon, 2019-06-10 at 09:49 +0900, Kuninori Morimoto wrote:

From: Kuninori Morimoto kuninori.morimoto.gx@renesas.com

commit 34ac3c3eb8f0c07 ("ASoC: core: lock client_mutex while removing link components") added mutex_lock() at soc_remove_link_components().

Is is called from snd_soc_unbind_card()

snd_soc_unbind_card() => soc_remove_link_components() soc_cleanup_card_resources() soc_remove_dai_links() => soc_remove_link_components()

And, there are 2 way to call it.

(1) snd_soc_unregister_component() ** mutex_lock() snd_soc_component_del_unlocked() => snd_soc_unbind_card() ** mutex_unlock()

(2) snd_soc_unregister_card() => snd_soc_unbind_card()

(1) case is already using mutex_lock() when it calles snd_soc_unbind_card(), thus, we will get lockdep warning. We need mutex_lock() under snd_soc_unregister_card() instead of snd_remove_link_components().

Thanks, Morimoto-san. I submitted a solution to fix the deadlock just a couple of days ago as well ( https://mailman.alsa-project.org/pipermail/alsa-devel/2019-June/150764.html ).

I am fine with either solution though.

Thanks, Ranjani

Fixes: 34ac3c3eb8f0c07 ("ASoC: core: lock client_mutex while removing link components") Signed-off-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com

---

sound/soc/soc-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 94a36ee..1679990 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -1018,14 +1018,12 @@ static void soc_remove_link_components(struct snd_soc_card *card, struct snd_soc_component *component; struct snd_soc_rtdcom_list *rtdcom;

• mutex_lock(&client_mutex); for_each_rtdcom(rtd, rtdcom) { component = rtdcom->component;

  if (component->driver->remove_order == order) soc_remove_component(component); }

• mutex_unlock(&client_mutex);

}

static void soc_remove_dai_links(struct snd_soc_card *card) @@ -2774,7 +2772,9 @@ static void snd_soc_unbind_card(struct snd_soc_card *card, bool unregister) */ int snd_soc_unregister_card(struct snd_soc_card *card) {

• mutex_lock(&client_mutex); snd_soc_unbind_card(card, true);
• mutex_unlock(&client_mutex); dev_dbg(card->dev, "ASoC: Unregistered card '%s'\n", card-

...

name);

return 0;