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ASoC: core: move DAI pre-links initiation to snd_soc_instantiate_card

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Kernel crashes when an ASoC component rebinding.

The dai_link->platforms has been reset to NULL by soc_cleanup_platform()
in soc_cleanup_card_resources() when un-registering component.  However,
it has no chance to re-allocate the dai_link->platforms when registering
the component again.

Move the DAI pre-links initiation from snd_soc_register_card() to
snd_soc_instantiate_card() to make sure all DAI pre-links get initiated
when component rebinding.

As an example, by using the following commands:
- echo -n max98357a > /sys/bus/platform/drivers/max98357a/unbind
- echo -n max98357a > /sys/bus/platform/drivers/max98357a/bind

Got the error message:
"Unable to handle kernel NULL pointer dereference at virtual address".

The call trace:
snd_soc_is_matching_component+0x30/0x6c
soc_bind_dai_link+0x16c/0x240
snd_soc_bind_card+0x1e4/0xb10
snd_soc_add_component+0x270/0x300
snd_soc_register_component+0x54/0x6c

Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Tzung-Bi Shih 2019-06-04 11:31:02 +08:00 committed by Mark Brown
parent 9bbc799318
commit 70fc53734e
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 10 additions and 17 deletions
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27
sound/soc/soc-core.c
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@ -2072,6 +2072,16 @@ static int snd_soc_instantiate_card(struct snd_soc_card *card)
int ret, i, order;
mutex_lock(&client_mutex);
for_each_card_prelinks(card, i, dai_link) {
ret = soc_init_dai_link(card, dai_link);
if (ret) {
soc_cleanup_platform(card);
dev_err(card->dev, "ASoC: failed to init link %s: %d\n",
dai_link->name, ret);
mutex_unlock(&client_mutex);
return ret;
}
}
mutex_lock_nested(&card->mutex, SND_SOC_CARD_CLASS_INIT);
card->dapm.bias_level = SND_SOC_BIAS_OFF;
@ -2796,26 +2806,9 @@ static int snd_soc_bind_card(struct snd_soc_card *card)
*/
int snd_soc_register_card(struct snd_soc_card *card)
{
int i, ret;
struct snd_soc_dai_link *link;
if (!card->name || !card->dev)
return -EINVAL;
mutex_lock(&client_mutex);
for_each_card_prelinks(card, i, link) {
ret = soc_init_dai_link(card, link);
if (ret) {
soc_cleanup_platform(card);
dev_err(card->dev, "ASoC: failed to init link %s\n",
link->name);
mutex_unlock(&client_mutex);
return ret;
}
}
mutex_unlock(&client_mutex);
dev_set_drvdata(card->dev, card);
snd_soc_initialize_card_lists(card);