evie/android_kernel_oneplus_msm8998
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ASoC: Add locking in DAPM widget power update

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While playback and capture is done concurrently the dapm widget
data is accessed parallelly which results in data corruption and
kernel panic. Fix this problem by serializing the stream event
operation by adding lock

dapm_seq_run will invoke dapm power sequence for pre-sorted list
of widgets to be powered up. Kernel panic issue is observed
during stability runs with the above sequence caused by null
pointer dereference in dapm_seq_run_coalesced. Fix kernel panic
issue by checking for valid snd_soc_dapm_context pointer in
dapm_seq_run before invoking dapm_seq_run_coalesced

Widget list in dapm is getting corrupted during concurrent
use cases where dapm_power_widget is accessed. This corruption
is resulting in kernel crash in dapm. Fix the issue by adding
protection in dapm_power_widgets API.

Change-Id: I49d19860277726cf3152e104ab40627fd56c021c
CRs-Fixed: 388785
Signed-off-by: Sriranjan Srikantam <cssrika@codeaurora.org>
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>
This commit is contained in:
Banajit Goswami 2015-04-10 16:50:43 -07:00 • committed by David Keitel
parent 42152f3e36
commit 2b5acaa668
3 changed files with 6 additions and 2 deletions
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1
include/sound/soc.h
View file

@ -1090,6 +1090,7 @@ struct snd_soc_card {
struct mutex mutex;
struct mutex dapm_mutex;
struct mutex dapm_power_mutex;
bool instantiated;

1
sound/soc/soc-core.c
View file

@ -2436,6 +2436,7 @@ int snd_soc_register_card(struct snd_soc_card *card)
card->instantiated = 0;
mutex_init(&card->mutex);
mutex_init(&card->dapm_mutex);
mutex_init(&card->dapm_power_mutex);
ret = snd_soc_instantiate_card(card);
if (ret != 0)

6
sound/soc/soc-dapm.c
View file

@ -1481,7 +1481,7 @@ static void dapm_seq_run(struct snd_soc_card *card,
/* Do we need to apply any queued changes? */
if (sort[w->id] != cur_sort || w->reg != cur_reg ||
w->dapm != cur_dapm || w->subseq != cur_subseq) {
if (!list_empty(&pending))
if (cur_dapm && !list_empty(&pending))
dapm_seq_run_coalesced(card, &pending);
if (cur_dapm && cur_dapm->seq_notifier) {
@ -1544,7 +1544,7 @@ static void dapm_seq_run(struct snd_soc_card *card,
"ASoC: Failed to apply widget power: %d\n", ret);
}
if (!list_empty(&pending))
if (cur_dapm && !list_empty(&pending))
dapm_seq_run_coalesced(card, &pending);
if (cur_dapm && cur_dapm->seq_notifier) {
@ -1780,6 +1780,7 @@ static int dapm_power_widgets(struct snd_soc_card *card, int event)
lockdep_assert_held(&card->dapm_mutex);
trace_snd_soc_dapm_start(card);
mutex_lock(&dapm->card->dapm_power_mutex);
list_for_each_entry(d, &card->dapm_list, list) {
if (dapm_idle_bias_off(d))
@ -1898,6 +1899,7 @@ static int dapm_power_widgets(struct snd_soc_card *card, int event)
pop_dbg(card->dev, card->pop_time,
"DAPM sequencing finished, waiting %dms\n", card->pop_time);
pop_wait(card->pop_time);
mutex_unlock(&dapm->card->dapm_power_mutex);
trace_snd_soc_dapm_done(card);