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ALSA: jack: Access input_dev under mutex

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It is possible when using ASoC that input_dev is unregistered while
calling snd_jack_report, which causes NULL pointer dereference.
In order to prevent this serialize access to input_dev using mutex lock.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220412091628.3056922-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Amadeusz Sławiński 2022-04-12 11:16:28 +02:00 committed by Takashi Iwai
parent 8f06bd1f89
commit 1b6a6fc528
2 changed files with 28 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/sound/jack.h
View File

@ -62,6 +62,7 @@ struct snd_jack {
const char *id;
#ifdef CONFIG_SND_JACK_INPUT_DEV
struct input_dev *input_dev;
struct mutex input_dev_lock;
int registered;
int type;
char name[100];

34
sound/core/jack.c
View File

@ -42,8 +42,11 @@ static int snd_jack_dev_disconnect(struct snd_device *device)
#ifdef CONFIG_SND_JACK_INPUT_DEV
struct snd_jack *jack = device->device_data;
if (!jack->input_dev)
mutex_lock(&jack->input_dev_lock);
if (!jack->input_dev) {
mutex_unlock(&jack->input_dev_lock);
return 0;
}
/* If the input device is registered with the input subsystem
* then we need to use a different deallocator. */
@ -52,6 +55,7 @@ static int snd_jack_dev_disconnect(struct snd_device *device)
else
input_free_device(jack->input_dev);
jack->input_dev = NULL;
mutex_unlock(&jack->input_dev_lock);
#endif /* CONFIG_SND_JACK_INPUT_DEV */
return 0;
}
@ -90,8 +94,11 @@ static int snd_jack_dev_register(struct snd_device *device)
snprintf(jack->name, sizeof(jack->name), "%s %s",
card->shortname, jack->id);
if (!jack->input_dev)
mutex_lock(&jack->input_dev_lock);
if (!jack->input_dev) {
mutex_unlock(&jack->input_dev_lock);
return 0;
}
jack->input_dev->name = jack->name;
@ -116,6 +123,7 @@ static int snd_jack_dev_register(struct snd_device *device)
if (err == 0)
jack->registered = 1;
mutex_unlock(&jack->input_dev_lock);
return err;
}
#endif /* CONFIG_SND_JACK_INPUT_DEV */
@ -517,9 +525,11 @@ int snd_jack_new(struct snd_card *card, const char *id, int type,
return -ENOMEM;
}
/* don't creat input device for phantom jack */
if (!phantom_jack) {
#ifdef CONFIG_SND_JACK_INPUT_DEV
mutex_init(&jack->input_dev_lock);
/* don't create input device for phantom jack */
if (!phantom_jack) {
int i;
jack->input_dev = input_allocate_device();
@ -537,8 +547,8 @@ int snd_jack_new(struct snd_card *card, const char *id, int type,
input_set_capability(jack->input_dev, EV_SW,
jack_switch_types[i]);
#endif /* CONFIG_SND_JACK_INPUT_DEV */
}
#endif /* CONFIG_SND_JACK_INPUT_DEV */
err = snd_device_new(card, SNDRV_DEV_JACK, jack, &ops);
if (err < 0)
@ -578,10 +588,14 @@ EXPORT_SYMBOL(snd_jack_new);
void snd_jack_set_parent(struct snd_jack *jack, struct device *parent)
{
WARN_ON(jack->registered);
if (!jack->input_dev)
mutex_lock(&jack->input_dev_lock);
if (!jack->input_dev) {
mutex_unlock(&jack->input_dev_lock);
return;
}
jack->input_dev->dev.parent = parent;
mutex_unlock(&jack->input_dev_lock);
}
EXPORT_SYMBOL(snd_jack_set_parent);
@ -629,6 +643,8 @@ EXPORT_SYMBOL(snd_jack_set_key);
/**
* snd_jack_report - Report the current status of a jack
* Note: This function uses mutexes and should be called from a
* context which can sleep (such as a workqueue).
*
* @jack: The jack to report status for
* @status: The current status of the jack
@ -654,8 +670,11 @@ void snd_jack_report(struct snd_jack *jack, int status)
status & jack_kctl->mask_bits);
#ifdef CONFIG_SND_JACK_INPUT_DEV
if (!jack->input_dev)
mutex_lock(&jack->input_dev_lock);
if (!jack->input_dev) {
mutex_unlock(&jack->input_dev_lock);
return;
}
for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
int testbit = ((SND_JACK_BTN_0 >> i) & ~mask_bits);
@ -675,6 +694,7 @@ void snd_jack_report(struct snd_jack *jack, int status)
}
input_sync(jack->input_dev);
mutex_unlock(&jack->input_dev_lock);
#endif /* CONFIG_SND_JACK_INPUT_DEV */
}
EXPORT_SYMBOL(snd_jack_report);