[PATCH AUTOSEL 5.1 131/219] ASoC: soc-core: call snd_soc_unbind_card() under mutex_lock;

Sasha Levin
2019-07-15T14:11:45Z

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

[ Upstream commit b545542a0b866f7975254e41c595836e9bc0ff2f ]

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.

commit 495f926c68ddb90 ("ASoC: core: Fix deadlock in
snd_soc_instantiate_card()") tried to fixup it, but still not
enough. We still have lockdep warning when we try unbind/bind.

We need mutex_lock() under snd_soc_unregister_card()
instead of snd_remove_link_components()/snd_soc_unbind_card().

Fixes: 34ac3c3eb8f0c07 ("ASoC: core: lock client_mutex while removing link components")
Fixes: 495f926c68ddb90 ("ASoC: core: Fix deadlock in snd_soc_instantiate_card()")
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 c010cc864cf3..f05a5c0a8aff 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -2834,14 +2834,12 @@ static void snd_soc_unbind_card(struct snd_soc_card *card, bool unregister)
snd_soc_dapm_shutdown(card);
snd_soc_flush_all_delayed_work(card);

- mutex_lock(&client_mutex);
/* remove all components used by DAI links on this card */
for_each_comp_order(order) {
for_each_card_rtds(card, rtd) {
soc_remove_link_components(card, rtd, order);
}
}
- mutex_unlock(&client_mutex);

soc_cleanup_card_resources(card);
if (!unregister)
@@ -2860,7 +2858,9 @@ 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;
--
2.20.1