Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9b0573c0 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: PCM: Fix some races at disconnection 



Fix races at PCM disconnection:
- while a PCM device is being opened or closed
- while the PCM state is being changed without lock in prepare,
  hw_params, hw_free ops

Reported-by: default avatarMatthieu CASTET <matthieu.castet@parrot.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 1693849f

sound/core/pcm.c

+6 −1
Original line number Diff line number Diff line
@@ -1086,11 +1086,15 @@ static int snd_pcm_dev_disconnect(struct snd_device *device) 
	if (list_empty(&pcm->list))

		goto unlock;



	mutex_lock(&pcm->open_mutex);

	list_del_init(&pcm->list);

	for (cidx = 0; cidx < 2; cidx++)

		for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)

		for (substream = pcm->streams[cidx].substream; substream; substream = substream->next) {

			snd_pcm_stream_lock_irq(substream);

			if (substream->runtime)

				substream->runtime->status->state = SNDRV_PCM_STATE_DISCONNECTED;

			snd_pcm_stream_unlock_irq(substream);

		}

	list_for_each_entry(notify, &snd_pcm_notify_list, list) {

		notify->n_disconnect(pcm);

	}
@@ -1110,6 +1114,7 @@ static int snd_pcm_dev_disconnect(struct snd_device *device) 
			pcm->streams[cidx].chmap_kctl = NULL;

		}

	}

	mutex_unlock(&pcm->open_mutex);

 unlock:

	mutex_unlock(&register_mutex);

	return 0;

sound/core/pcm_native.c

+12 −4
Original line number Diff line number Diff line
@@ -369,6 +369,14 @@ static int period_to_usecs(struct snd_pcm_runtime *runtime) 
	return usecs;

}



static void snd_pcm_set_state(struct snd_pcm_substream *substream, int state)

{

	snd_pcm_stream_lock_irq(substream);

	if (substream->runtime->status->state != SNDRV_PCM_STATE_DISCONNECTED)

		substream->runtime->status->state = state;

	snd_pcm_stream_unlock_irq(substream);

}



static int snd_pcm_hw_params(struct snd_pcm_substream *substream,

			     struct snd_pcm_hw_params *params)

{
@@ -452,7 +460,7 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream, 
		runtime->boundary *= 2;



	snd_pcm_timer_resolution_change(substream);

	runtime->status->state = SNDRV_PCM_STATE_SETUP;

	snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP);



	if (pm_qos_request_active(&substream->latency_pm_qos_req))

		pm_qos_remove_request(&substream->latency_pm_qos_req);
@@ -464,7 +472,7 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream, 
	/* hardware might be unusable from this time,

	   so we force application to retry to set

	   the correct hardware parameter settings */

	runtime->status->state = SNDRV_PCM_STATE_OPEN;

	snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);

	if (substream->ops->hw_free != NULL)

		substream->ops->hw_free(substream);

	return err;
@@ -512,7 +520,7 @@ static int snd_pcm_hw_free(struct snd_pcm_substream *substream) 
		return -EBADFD;

	if (substream->ops->hw_free)

		result = substream->ops->hw_free(substream);

	runtime->status->state = SNDRV_PCM_STATE_OPEN;

	snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);

	pm_qos_remove_request(&substream->latency_pm_qos_req);

	return result;

}
@@ -1320,7 +1328,7 @@ static void snd_pcm_post_prepare(struct snd_pcm_substream *substream, int state) 
{

	struct snd_pcm_runtime *runtime = substream->runtime;

	runtime->control->appl_ptr = runtime->status->hw_ptr;

	runtime->status->state = SNDRV_PCM_STATE_PREPARED;

	snd_pcm_set_state(substream, SNDRV_PCM_STATE_PREPARED);

}



static struct action_ops snd_pcm_action_prepare = {