@@ -1083,6 +1083,8 @@ struct snd_soc_card {
struct mutex mutex;
struct mutex dapm_mutex;
+ spinlock_t dpcm_lock;
+
bool instantiated;
bool topology_shortname_created;
@@ -2820,6 +2820,7 @@ int snd_soc_register_card(struct snd_soc_card *card)
card->instantiated = 0;
mutex_init(&card->mutex);
mutex_init(&card->dapm_mutex);
+ spin_lock_init(&card->dpcm_lock);
return snd_soc_bind_card(card);
}
@@ -1228,8 +1228,10 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
dpcm->fe = fe;
be->dpcm[stream].runtime = fe->dpcm[stream].runtime;
dpcm->state = SND_SOC_DPCM_LINK_STATE_NEW;
+ spin_lock(&fe->card->dpcm_lock);
list_add(&dpcm->list_be, &fe->dpcm[stream].be_clients);
list_add(&dpcm->list_fe, &be->dpcm[stream].fe_clients);
+ spin_unlock(&fe->card->dpcm_lock);
dev_dbg(fe->dev, "connected new DPCM %s path %s %s %s\n",
stream ? "capture" : "playback", fe->dai_link->name,
@@ -1294,8 +1296,10 @@ void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
#ifdef CONFIG_DEBUG_FS
debugfs_remove(dpcm->debugfs_state);
#endif
+ spin_lock(&fe->card->dpcm_lock);
list_del(&dpcm->list_be);
list_del(&dpcm->list_fe);
+ spin_unlock(&fe->card->dpcm_lock);
kfree(dpcm);
}
}
@@ -1548,9 +1552,11 @@ void dpcm_clear_pending_state(struct snd_soc_pcm_runtime *fe, int stream)
{
struct snd_soc_dpcm *dpcm;
+ spin_lock(&fe->card->dpcm_lock);
for_each_dpcm_be(fe, stream, dpcm)
dpcm->be->dpcm[stream].runtime_update =
SND_SOC_DPCM_UPDATE_NO;
+ spin_unlock(&fe->card->dpcm_lock);
}
static void dpcm_be_dai_startup_unwind(struct snd_soc_pcm_runtime *fe,
@@ -2640,11 +2646,13 @@ static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
dpcm_be_dai_shutdown(fe, stream);
disconnect:
/* disconnect any non started BEs */
+ spin_lock(&fe->card->dpcm_lock);
for_each_dpcm_be(fe, stream, dpcm) {
struct snd_soc_pcm_runtime *be = dpcm->be;
if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START)
dpcm->state = SND_SOC_DPCM_LINK_STATE_FREE;
}
+ spin_unlock(&fe->card->dpcm_lock);
return ret;
}
@@ -3220,7 +3228,9 @@ int snd_soc_dpcm_can_be_free_stop(struct snd_soc_pcm_runtime *fe,
{
struct snd_soc_dpcm *dpcm;
int state;
+ int ret = 1;
+ spin_lock(&fe->card->dpcm_lock);
for_each_dpcm_fe(be, stream, dpcm) {
if (dpcm->fe == fe)
@@ -3229,12 +3239,15 @@ int snd_soc_dpcm_can_be_free_stop(struct snd_soc_pcm_runtime *fe,
state = dpcm->fe->dpcm[stream].state;
if (state == SND_SOC_DPCM_STATE_START ||
state == SND_SOC_DPCM_STATE_PAUSED ||
- state == SND_SOC_DPCM_STATE_SUSPEND)
- return 0;
+ state == SND_SOC_DPCM_STATE_SUSPEND) {
+ ret = 0;
+ break;
+ }
}
+ spin_unlock(&fe->card->dpcm_lock);
/* it's safe to free/stop this BE DAI */
- return 1;
+ return ret;
}
EXPORT_SYMBOL_GPL(snd_soc_dpcm_can_be_free_stop);
@@ -3247,7 +3260,9 @@ int snd_soc_dpcm_can_be_params(struct snd_soc_pcm_runtime *fe,
{
struct snd_soc_dpcm *dpcm;
int state;
+ int ret = 1;
+ spin_lock(&fe->card->dpcm_lock);
for_each_dpcm_fe(be, stream, dpcm) {
if (dpcm->fe == fe)
@@ -3257,12 +3272,15 @@ int snd_soc_dpcm_can_be_params(struct snd_soc_pcm_runtime *fe,
if (state == SND_SOC_DPCM_STATE_START ||
state == SND_SOC_DPCM_STATE_PAUSED ||
state == SND_SOC_DPCM_STATE_SUSPEND ||
- state == SND_SOC_DPCM_STATE_PREPARE)
- return 0;
+ state == SND_SOC_DPCM_STATE_PREPARE) {
+ ret = 0;
+ break;
+ }
}
+ spin_unlock(&fe->card->dpcm_lock);
/* it's safe to change hw_params */
- return 1;
+ return ret;
}
EXPORT_SYMBOL_GPL(snd_soc_dpcm_can_be_params);
@@ -3328,6 +3346,7 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
goto out;
}
+ spin_lock(&fe->card->dpcm_lock);
for_each_dpcm_be(fe, stream, dpcm) {
struct snd_soc_pcm_runtime *be = dpcm->be;
params = &dpcm->hw_params;
@@ -3348,7 +3367,7 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
params_channels(params),
params_rate(params));
}
-
+ spin_unlock(&fe->card->dpcm_lock);
out:
return offset;
}
The dpcm get from fe_clients/be_clients may be free before use Add a spin lock at snd_soc_card level, to protect the dpcm instance. The lock may be used in atomic context, so use spin lock. possible race condition between void dpcm_be_disconnect( ... list_del(&dpcm->list_be); list_del(&dpcm->list_fe); kfree(dpcm); ... and for_each_dpcm_fe() for_each_dpcm_be*() race condition example Thread 1: snd_soc_dapm_mixer_update_power() -> soc_dpcm_runtime_update() -> dpcm_be_disconnect() -> kfree(dpcm); Thread 2: dpcm_fe_dai_trigger() -> dpcm_be_dai_trigger() -> snd_soc_dpcm_can_be_free_stop() -> if (dpcm->fe == fe) Excpetion Scenario: two FE link to same BE FE1 -> BE FE2 -> Thread 1: switch of mixer between FE2 -> BE Thread 2: pcm_stop FE1 Exception: Unable to handle kernel paging request at virtual address dead0000000000e0 pc=<> [<ffffff8960e2cd10>] dpcm_be_dai_trigger+0x29c/0x47c sound/soc/soc-pcm.c:3226 if (dpcm->fe == fe) lr=<> [<ffffff8960e2f694>] dpcm_fe_dai_do_trigger+0x94/0x26c Backtrace: [<ffffff89602dba80>] notify_die+0x68/0xb8 [<ffffff896028c7dc>] die+0x118/0x2a8 [<ffffff89602a2f84>] __do_kernel_fault+0x13c/0x14c [<ffffff89602a27f4>] do_translation_fault+0x64/0xa0 [<ffffff8960280cf8>] do_mem_abort+0x4c/0xd0 [<ffffff8960282ad0>] el1_da+0x24/0x40 [<ffffff8960e2cd10>] dpcm_be_dai_trigger+0x29c/0x47c [<ffffff8960e2f694>] dpcm_fe_dai_do_trigger+0x94/0x26c [<ffffff8960e2edec>] dpcm_fe_dai_trigger+0x3c/0x44 [<ffffff8960de5588>] snd_pcm_do_stop+0x50/0x5c [<ffffff8960dded24>] snd_pcm_action+0xb4/0x13c [<ffffff8960ddfdb4>] snd_pcm_drop+0xa0/0x128 [<ffffff8960de69bc>] snd_pcm_common_ioctl+0x9d8/0x30f0 [<ffffff8960de1cac>] snd_pcm_ioctl_compat+0x29c/0x2f14 [<ffffff89604c9d60>] compat_SyS_ioctl+0x128/0x244 [<ffffff8960283740>] el0_svc_naked+0x34/0x38 [<ffffffffffffffff>] 0xffffffffffffffff Signed-off-by: KaiChieh Chuang <kaichieh.chuang@mediatek.com> --- include/sound/soc.h | 2 ++ sound/soc/soc-core.c | 1 + sound/soc/soc-pcm.c | 33 ++++++++++++++++++++++++++------- 3 files changed, 29 insertions(+), 7 deletions(-)