[PATCHv2] ASoC: xilinx: formatter_pcm: fix stream_data leak on open error

[Rosen Penev]

In xlnx_formatter_pcm_open(), stream_data is allocated and
adata->play_stream or adata->capture_stream is assigned early.  If a
later step, such as snd_pcm_hw_constraint_step() or
snd_pcm_hw_constraint_integer(), fails, the function returns the error
immediately.  ALSA does not call the close callback when open fails, so
stream_data is leaked and the stream pointer is left dangling, pointing
to a substream that ALSA frees.  A later interrupt would then call
snd_pcm_period_elapsed() on the freed substream.

Free stream_data and clear the stream pointer on the error paths.

Fixes: 6f6c3c36f091 ("ASoC: xlnx: add pcm formatter platform driver")
Assisted-by: opencode:deepseek-v4-flash-free
Signed-off-by: Rosen Penev <rosenp at gmail.com>
Reviewed-by: Michal Simek <michal.simek at amd.com>
---
 v2: change goto label from err to error.
 sound/soc/xilinx/xlnx_formatter_pcm.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/sound/soc/xilinx/xlnx_formatter_pcm.c b/sound/soc/xilinx/xlnx_formatter_pcm.c
index b50306b0fc06..3d6f1e4046d8 100644
--- a/sound/soc/xilinx/xlnx_formatter_pcm.c
+++ b/sound/soc/xilinx/xlnx_formatter_pcm.c
@@ -383,7 +383,7 @@ static int xlnx_formatter_pcm_open(struct snd_soc_component *component,
 	if (err) {
 		dev_err(component->dev,
 			"Unable to set constraint on period bytes\n");
-		return err;
+		goto error;
 	}
 
 	/* Resize the buffer bytes as divisible by 64 */
@@ -393,7 +393,7 @@ static int xlnx_formatter_pcm_open(struct snd_soc_component *component,
 	if (err) {
 		dev_err(component->dev,
 			"Unable to set constraint on buffer bytes\n");
-		return err;
+		goto error;
 	}
 
 	/* Set periods as integer multiple */
@@ -402,7 +402,7 @@ static int xlnx_formatter_pcm_open(struct snd_soc_component *component,
 	if (err < 0) {
 		dev_err(component->dev,
 			"Unable to set constraint on periods to be integer\n");
-		return err;
+		goto error;
 	}
 
 	/* enable DMA IOC irq */
@@ -411,6 +411,14 @@ static int xlnx_formatter_pcm_open(struct snd_soc_component *component,
 	writel(val, stream_data->mmio + XLNX_AUD_CTRL);
 
 	return 0;
+
+error:
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		adata->play_stream = NULL;
+	else
+		adata->capture_stream = NULL;
+	kfree(stream_data);
+	return err;
 }
 
 static int xlnx_formatter_pcm_close(struct snd_soc_component *component,
-- 
2.55.0