[alsa-devel] [PATCH 1/3] ASoC: Tegra: tegra_pcm_deallocate_dma_buffer: Don't OOPS

[Stephen Warren]

Not all PCM devices have all sub-streams. Specifically, the SPDIF driver
only supports playback and hence has no capture substream. Check whether
a substream exists before dereferencing it, when de-allocating DMA
buffers in tegra_pcm_deallocate_dma_buffer.

Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
 sound/soc/tegra/tegra_pcm.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/sound/soc/tegra/tegra_pcm.c b/sound/soc/tegra/tegra_pcm.c
index ff86e5e..c7cfd96 100644
--- a/sound/soc/tegra/tegra_pcm.c
+++ b/sound/soc/tegra/tegra_pcm.c
@@ -309,9 +309,14 @@ static int tegra_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
 
 static void tegra_pcm_deallocate_dma_buffer(struct snd_pcm *pcm, int stream)
 {
-	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
-	struct snd_dma_buffer *buf = &substream->dma_buffer;
+	struct snd_pcm_substream *substream;
+	struct snd_dma_buffer *buf;
+
+	substream = pcm->streams[stream].substream;
+	if (!substream)
+		return;
 
+	buf = &substream->dma_buffer;
 	if (!buf->area)
 		return;
 
-- 
1.7.0.4