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Commit 9685347a authored by Takashi Iwai's avatar Takashi Iwai
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ALSA: aloop: Release cable upon open error path 



The aloop runtime object and its assignment in the cable are left even
when opening a substream fails.  This doesn't mean any memory leak,
but it still keeps the invalid pointer that may be referred by the
another side of the cable spontaneously, which is a potential Oops
cause.

Clean up the cable assignment and the empty cable upon the error path
properly.

Fixes: 597603d6 ("ALSA: introduce the snd-aloop module for the PCM loopback")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent fb51f1cd

sound/drivers/aloop.c

+25 −13
Original line number Original line Diff line number Diff line
@@ -658,12 +658,31 @@ static int rule_channels(struct snd_pcm_hw_params *params, 
	return snd_interval_refine(hw_param_interval(params, rule->var), &t);

	return snd_interval_refine(hw_param_interval(params, rule->var), &t);

}

}





static void free_cable(struct snd_pcm_substream *substream)

{

	struct loopback *loopback = substream->private_data;

	int dev = get_cable_index(substream);

	struct loopback_cable *cable;



	cable = loopback->cables[substream->number][dev];

	if (!cable)

		return;

	if (cable->streams[!substream->stream]) {

		/* other stream is still alive */

		cable->streams[substream->stream] = NULL;

	} else {

		/* free the cable */

		loopback->cables[substream->number][dev] = NULL;

		kfree(cable);

	}

}



static int loopback_open(struct snd_pcm_substream *substream)

static int loopback_open(struct snd_pcm_substream *substream)

{

{

	struct snd_pcm_runtime *runtime = substream->runtime;

	struct snd_pcm_runtime *runtime = substream->runtime;

	struct loopback *loopback = substream->private_data;

	struct loopback *loopback = substream->private_data;

	struct loopback_pcm *dpcm;

	struct loopback_pcm *dpcm;

	struct loopback_cable *cable;

	struct loopback_cable *cable = NULL;

	int err = 0;

	int err = 0;

	int dev = get_cable_index(substream);

	int dev = get_cable_index(substream);
@@ -681,7 +700,6 @@ static int loopback_open(struct snd_pcm_substream *substream) 
	if (!cable) {

	if (!cable) {

		cable = kzalloc(sizeof(*cable), GFP_KERNEL);

		cable = kzalloc(sizeof(*cable), GFP_KERNEL);

		if (!cable) {

		if (!cable) {

			kfree(dpcm);

			err = -ENOMEM;

			err = -ENOMEM;

			goto unlock;

			goto unlock;

		}

		}
@@ -723,6 +741,10 @@ static int loopback_open(struct snd_pcm_substream *substream) 
	else

	else

		runtime->hw = cable->hw;

		runtime->hw = cable->hw;

 unlock:

 unlock:

	if (err < 0) {

		free_cable(substream);

		kfree(dpcm);

	}

	mutex_unlock(&loopback->cable_lock);

	mutex_unlock(&loopback->cable_lock);

	return err;

	return err;

}

}
@@ -731,20 +753,10 @@ static int loopback_close(struct snd_pcm_substream *substream) 
{

{

	struct loopback *loopback = substream->private_data;

	struct loopback *loopback = substream->private_data;

	struct loopback_pcm *dpcm = substream->runtime->private_data;

	struct loopback_pcm *dpcm = substream->runtime->private_data;

	struct loopback_cable *cable;

	int dev = get_cable_index(substream);





	loopback_timer_stop(dpcm);

	loopback_timer_stop(dpcm);

	mutex_lock(&loopback->cable_lock);

	mutex_lock(&loopback->cable_lock);

	cable = loopback->cables[substream->number][dev];

	free_cable(substream);

	if (cable->streams[!substream->stream]) {

		/* other stream is still alive */

		cable->streams[substream->stream] = NULL;

	} else {

		/* free the cable */

		loopback->cables[substream->number][dev] = NULL;

		kfree(cable);

	}

	mutex_unlock(&loopback->cable_lock);

	mutex_unlock(&loopback->cable_lock);

	return 0;

	return 0;

}

}