Merge tag 'sound-4.15-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound

Pull sound fixes from Takashi Iwai:
 "A collection of the last-minute small PCM fixes:

   - A workaround for the recent regression wrt PulseAudio

   - Removal of spurious WARN_ON() that is triggered by syzkaller

   - Fixes for aloop, hardening racy accesses

   - Fixes in PCM OSS emulation wrt the unabortable loops that may cause
     RCU stall"

* tag 'sound-4.15-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: pcm: Allow aborting mutex lock at OSS read/write loops
  ALSA: pcm: Abort properly at pending signal in OSS read/write loops
  ALSA: aloop: Fix racy hw constraints adjustment
  ALSA: aloop: Fix inconsistent format due to incomplete rule
  ALSA: aloop: Release cable upon open error path
  ALSA: pcm: Workaround for weird PulseAudio behavior on rewind error
  ALSA: pcm: Add missing error checks in OSS emulation plugin builder
  ALSA: pcm: Remove incorrect snd_BUG_ON() usages

5 files changed, 97 insertions, 69 deletions

diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index e49f448ee04f..c2db7e905f7d 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -455,7 +455,6 @@ static int snd_pcm_hw_param_near(struct snd_pcm_substream *pcm,
 		v = snd_pcm_hw_param_last(pcm, params, var, dir);
 	else
 		v = snd_pcm_hw_param_first(pcm, params, var, dir);
-	snd_BUG_ON(v < 0);
 	return v;
 }
 
@@ -1335,8 +1334,11 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
 
 	if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
 		return tmp;
-	mutex_lock(&runtime->oss.params_lock);
 	while (bytes > 0) {
+		if (mutex_lock_interruptible(&runtime->oss.params_lock)) {
+			tmp = -ERESTARTSYS;
+			break;
+		}
 		if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
 			tmp = bytes;
 			if (tmp + runtime->oss.buffer_used > runtime->oss.period_bytes)
@@ -1380,14 +1382,18 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
 			xfer += tmp;
 			if ((substream->f_flags & O_NONBLOCK) != 0 &&
 			    tmp != runtime->oss.period_bytes)
-				break;
+				tmp = -EAGAIN;
 		}
-	}
-	mutex_unlock(&runtime->oss.params_lock);
-	return xfer;
-
  err:
-	mutex_unlock(&runtime->oss.params_lock);
+		mutex_unlock(&runtime->oss.params_lock);
+		if (tmp < 0)
+			break;
+		if (signal_pending(current)) {
+			tmp = -ERESTARTSYS;
+			break;
+		}
+		tmp = 0;
+	}
 	return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp;
 }
 
@@ -1435,8 +1441,11 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use
 
 	if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
 		return tmp;
-	mutex_lock(&runtime->oss.params_lock);
 	while (bytes > 0) {
+		if (mutex_lock_interruptible(&runtime->oss.params_lock)) {
+			tmp = -ERESTARTSYS;
+			break;
+		}
 		if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
 			if (runtime->oss.buffer_used == 0) {
 				tmp = snd_pcm_oss_read2(substream, runtime->oss.buffer, runtime->oss.period_bytes, 1);
@@ -1467,12 +1476,16 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use
 			bytes -= tmp;
 			xfer += tmp;
 		}
-	}
-	mutex_unlock(&runtime->oss.params_lock);
-	return xfer;
-
  err:
-	mutex_unlock(&runtime->oss.params_lock);
+		mutex_unlock(&runtime->oss.params_lock);
+		if (tmp < 0)
+			break;
+		if (signal_pending(current)) {
+			tmp = -ERESTARTSYS;
+			break;
+		}
+		tmp = 0;
+	}
 	return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp;
 }
 
diff --git a/sound/core/oss/pcm_plugin.c b/sound/core/oss/pcm_plugin.c
index cadc93792868..85a56af104bd 100644
--- a/sound/core/oss/pcm_plugin.c
+++ b/sound/core/oss/pcm_plugin.c
@@ -592,18 +592,26 @@ snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *plug, st
 	snd_pcm_sframes_t frames = size;
 
 	plugin = snd_pcm_plug_first(plug);
-	while (plugin && frames > 0) {
+	while (plugin) {
+		if (frames <= 0)
+			return frames;
 		if ((next = plugin->next) != NULL) {
 			snd_pcm_sframes_t frames1 = frames;
-			if (plugin->dst_frames)
+			if (plugin->dst_frames) {
 				frames1 = plugin->dst_frames(plugin, frames);
+				if (frames1 <= 0)
+					return frames1;
+			}
 			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
 				return err;
 			}
 			if (err != frames1) {
 				frames = err;
-				if (plugin->src_frames)
+				if (plugin->src_frames) {
 					frames = plugin->src_frames(plugin, frames1);
+					if (frames <= 0)
+						return frames;
+				}
 			}
 		} else
 			dst_channels = NULL;
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 10e7ef7a8804..db7894bb028c 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1632,7 +1632,7 @@ int snd_pcm_hw_param_first(struct snd_pcm_substream *pcm,
 		return changed;
 	if (params->rmask) {
 		int err = snd_pcm_hw_refine(pcm, params);
-		if (snd_BUG_ON(err < 0))
+		if (err < 0)
 			return err;
 	}
 	return snd_pcm_hw_param_value(params, var, dir);
@@ -1678,7 +1678,7 @@ int snd_pcm_hw_param_last(struct snd_pcm_substream *pcm,
 		return changed;
 	if (params->rmask) {
 		int err = snd_pcm_hw_refine(pcm, params);
-		if (snd_BUG_ON(err < 0))
+		if (err < 0)
 			return err;
 	}
 	return snd_pcm_hw_param_value(params, var, dir);
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index a4d92e46c459..f08772568c17 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -2580,7 +2580,7 @@ static snd_pcm_sframes_t forward_appl_ptr(struct snd_pcm_substream *substream,
 	return ret < 0 ? ret : frames;
 }
 
-/* decrease the appl_ptr; returns the processed frames or a negative error */
+/* decrease the appl_ptr; returns the processed frames or zero for error */
 static snd_pcm_sframes_t rewind_appl_ptr(struct snd_pcm_substream *substream,
 					 snd_pcm_uframes_t frames,
 					 snd_pcm_sframes_t avail)
@@ -2597,7 +2597,12 @@ static snd_pcm_sframes_t rewind_appl_ptr(struct snd_pcm_substream *substream,
 	if (appl_ptr < 0)
 		appl_ptr += runtime->boundary;
 	ret = pcm_lib_apply_appl_ptr(substream, appl_ptr);
-	return ret < 0 ? ret : frames;
+	/* NOTE: we return zero for errors because PulseAudio gets depressed
+	 * upon receiving an error from rewind ioctl and stops processing
+	 * any longer.  Returning zero means that no rewind is done, so
+	 * it's not absolutely wrong to answer like that.
+	 */
+	return ret < 0 ? 0 : frames;
 }
 
 static snd_pcm_sframes_t snd_pcm_playback_rewind(struct snd_pcm_substream *substream,
diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
index afac886ffa28..0333143a1fa7 100644
--- a/sound/drivers/aloop.c
+++ b/sound/drivers/aloop.c
@@ -39,6 +39,7 @@
 #include <sound/core.h>
 #include <sound/control.h>
 #include <sound/pcm.h>
+#include <sound/pcm_params.h>
 #include <sound/info.h>
 #include <sound/initval.h>
 
@@ -305,19 +306,6 @@ static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 	return 0;
 }
 
-static void params_change_substream(struct loopback_pcm *dpcm,
-				    struct snd_pcm_runtime *runtime)
-{
-	struct snd_pcm_runtime *dst_runtime;
-
-	if (dpcm == NULL || dpcm->substream == NULL)
-		return;
-	dst_runtime = dpcm->substream->runtime;
-	if (dst_runtime == NULL)
-		return;
-	dst_runtime->hw = dpcm->cable->hw;
-}
-
 static void params_change(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
@@ -329,10 +317,6 @@ static void params_change(struct snd_pcm_substream *substream)
 	cable->hw.rate_max = runtime->rate;
 	cable->hw.channels_min = runtime->channels;
 	cable->hw.channels_max = runtime->channels;
-	params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
-				runtime);
-	params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE],
-				runtime);
 }
 
 static int loopback_prepare(struct snd_pcm_substream *substream)
@@ -620,26 +604,29 @@ static unsigned int get_cable_index(struct snd_pcm_substream *substream)
 static int rule_format(struct snd_pcm_hw_params *params,
 		       struct snd_pcm_hw_rule *rule)
 {
+	struct loopback_pcm *dpcm = rule->private;
+	struct loopback_cable *cable = dpcm->cable;
+	struct snd_mask m;
 
-	struct snd_pcm_hardware *hw = rule->private;
-	struct snd_mask *maskp = hw_param_mask(params, rule->var);
-
-	maskp->bits[0] &= (u_int32_t)hw->formats;
-	maskp->bits[1] &= (u_int32_t)(hw->formats >> 32);
-	memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
-	if (! maskp->bits[0] && ! maskp->bits[1])
-		return -EINVAL;
-	return 0;
+	snd_mask_none(&m);
+	mutex_lock(&dpcm->loopback->cable_lock);
+	m.bits[0] = (u_int32_t)cable->hw.formats;
+	m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
+	mutex_unlock(&dpcm->loopback->cable_lock);
+	return snd_mask_refine(hw_param_mask(params, rule->var), &m);
 }
 
 static int rule_rate(struct snd_pcm_hw_params *params,
 		     struct snd_pcm_hw_rule *rule)
 {
-	struct snd_pcm_hardware *hw = rule->private;
+	struct loopback_pcm *dpcm = rule->private;
+	struct loopback_cable *cable = dpcm->cable;
 	struct snd_interval t;
 
-        t.min = hw->rate_min;
-        t.max = hw->rate_max;
+	mutex_lock(&dpcm->loopback->cable_lock);
+	t.min = cable->hw.rate_min;
+	t.max = cable->hw.rate_max;
+	mutex_unlock(&dpcm->loopback->cable_lock);
         t.openmin = t.openmax = 0;
         t.integer = 0;
 	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
@@ -648,22 +635,44 @@ static int rule_rate(struct snd_pcm_hw_params *params,
 static int rule_channels(struct snd_pcm_hw_params *params,
 			 struct snd_pcm_hw_rule *rule)
 {
-	struct snd_pcm_hardware *hw = rule->private;
+	struct loopback_pcm *dpcm = rule->private;
+	struct loopback_cable *cable = dpcm->cable;
 	struct snd_interval t;
 
-        t.min = hw->channels_min;
-        t.max = hw->channels_max;
+	mutex_lock(&dpcm->loopback->cable_lock);
+	t.min = cable->hw.channels_min;
+	t.max = cable->hw.channels_max;
+	mutex_unlock(&dpcm->loopback->cable_lock);
         t.openmin = t.openmax = 0;
         t.integer = 0;
 	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)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct loopback *loopback = substream->private_data;
 	struct loopback_pcm *dpcm;
-	struct loopback_cable *cable;
+	struct loopback_cable *cable = NULL;
 	int err = 0;
 	int dev = get_cable_index(substream);
 
@@ -681,7 +690,6 @@ static int loopback_open(struct snd_pcm_substream *substream)
 	if (!cable) {
 		cable = kzalloc(sizeof(*cable), GFP_KERNEL);
 		if (!cable) {
-			kfree(dpcm);
 			err = -ENOMEM;
 			goto unlock;
 		}
@@ -699,19 +707,19 @@ static int loopback_open(struct snd_pcm_substream *substream)
 	/* are cached -> they do not reflect the actual state */
 	err = snd_pcm_hw_rule_add(runtime, 0,
 				  SNDRV_PCM_HW_PARAM_FORMAT,
-				  rule_format, &runtime->hw,
+				  rule_format, dpcm,
 				  SNDRV_PCM_HW_PARAM_FORMAT, -1);
 	if (err < 0)
 		goto unlock;
 	err = snd_pcm_hw_rule_add(runtime, 0,
 				  SNDRV_PCM_HW_PARAM_RATE,
-				  rule_rate, &runtime->hw,
+				  rule_rate, dpcm,
 				  SNDRV_PCM_HW_PARAM_RATE, -1);
 	if (err < 0)
 		goto unlock;
 	err = snd_pcm_hw_rule_add(runtime, 0,
 				  SNDRV_PCM_HW_PARAM_CHANNELS,
-				  rule_channels, &runtime->hw,
+				  rule_channels, dpcm,
 				  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 	if (err < 0)
 		goto unlock;
@@ -723,6 +731,10 @@ static int loopback_open(struct snd_pcm_substream *substream)
 	else
 		runtime->hw = cable->hw;
  unlock:
+	if (err < 0) {
+		free_cable(substream);
+		kfree(dpcm);
+	}
 	mutex_unlock(&loopback->cable_lock);
 	return err;
 }
@@ -731,20 +743,10 @@ static int loopback_close(struct snd_pcm_substream *substream)
 {
 	struct loopback *loopback = substream->private_data;
 	struct loopback_pcm *dpcm = substream->runtime->private_data;
-	struct loopback_cable *cable;
-	int dev = get_cable_index(substream);
 
 	loopback_timer_stop(dpcm);
 	mutex_lock(&loopback->cable_lock);
-	cable = loopback->cables[substream->number][dev];
-	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);
-	}
+	free_cable(substream);
 	mutex_unlock(&loopback->cable_lock);
 	return 0;
 }