ASoC: soc-core: add snd_soc_find_dai_with_mutex()
authorKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Wed, 26 Aug 2020 23:55:39 +0000 (08:55 +0900)
committerMark Brown <broonie@kernel.org>
Thu, 27 Aug 2020 13:43:25 +0000 (14:43 +0100)
commitc1c277b2c425f69b9b4f4258d9db18562d9be041
treed5dc296bdc18b3a3f6adbb87423115fc4895b8f0
parenta11ffbbac9cc7fdd73b01a0d8227ef8a1d2b95da
ASoC: soc-core: add snd_soc_find_dai_with_mutex()

commit 25612477d20b52 ("ASoC: soc-dai: set dai_link dpcm_ flags with a helper")
added snd_soc_dai_link_set_capabilities().
But it is using snd_soc_find_dai() (A) which is required client_mutex (B).
And client_mutex is soc-core.c local.

struct snd_soc_dai *snd_soc_find_dai(xxx)
{
...
(B) lockdep_assert_held(&client_mutex);
...
}

void snd_soc_dai_link_set_capabilities(xxx)
{
...
for_each_pcm_streams(direction) {
...
for_each_link_cpus(dai_link, i, cpu) {
(A) dai = snd_soc_find_dai(cpu);
...
}
...
for_each_link_codecs(dai_link, i, codec) {
(A) dai = snd_soc_find_dai(codec);
...
}
}
...
}

Because of these background, we will get WARNING if .config has CONFIG_LOCKDEP.

WARNING: CPU: 2 PID: 53 at sound/soc/soc-core.c:814 snd_soc_find_dai+0xf8/0x100
CPU: 2 PID: 53 Comm: kworker/2:1 Not tainted 5.7.0-rc1+ #328
Hardware name: Renesas H3ULCB Kingfisher board based on r8a77951 (DT)
Workqueue: events deferred_probe_work_func
pstate: 60000005 (nZCv daif -PAN -UAO)
pc : snd_soc_find_dai+0xf8/0x100
lr : snd_soc_find_dai+0xf4/0x100
...
Call trace:
 snd_soc_find_dai+0xf8/0x100
 snd_soc_dai_link_set_capabilities+0xa0/0x16c
 graph_dai_link_of_dpcm+0x390/0x3c0
 graph_for_each_link+0x134/0x200
 graph_probe+0x144/0x230
 platform_drv_probe+0x5c/0xb0
 really_probe+0xe4/0x430
 driver_probe_device+0x60/0xf4

snd_soc_find_dai() will be used from (X) CPU/Codec/Platform driver with
mutex lock, and (Y) Card driver without mutex lock.
This snd_soc_dai_link_set_capabilities() is for Card driver,
this means called without mutex.
This patch adds snd_soc_find_dai_with_mutex() to solve it.

Fixes: 25612477d20b52 ("ASoC: soc-dai: set dai_link dpcm_ flags with a helper")
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87blixvuab.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>
include/sound/soc.h
sound/soc/soc-core.c
sound/soc/soc-dai.c