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: Matthieu CASTET <matthieu.castet@parrot.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 5e12e5b..8753c89 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -369,6 +369,14 @@
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 @@
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 @@
/* 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 @@
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 @@
{
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 = {