From bc0e7345168c0f7483d2d1da86285d89136417cd Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Tue, 20 Oct 2015 11:46:31 +0200
Subject: ALSA: pcm_dmaengine: Properly synchronize DMA on shutdown
Use the new dmaengine_synchronize() function to make sure that all complete
callbacks have finished running before the runtime data, which is accessed
in the completed callback, is freed.
This fixes a long standing use-after-free race condition that has been
observed on some systems.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
---
sound/core/pcm_dmaengine.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
(limited to 'sound/core')
diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c
index fba365a78390..697c166acf05 100644
--- a/sound/core/pcm_dmaengine.c
+++ b/sound/core/pcm_dmaengine.c
@@ -202,13 +202,13 @@ int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
if (runtime->info & SNDRV_PCM_INFO_PAUSE)
dmaengine_pause(prtd->dma_chan);
else
- dmaengine_terminate_all(prtd->dma_chan);
+ dmaengine_terminate_async(prtd->dma_chan);
break;
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
dmaengine_pause(prtd->dma_chan);
break;
case SNDRV_PCM_TRIGGER_STOP:
- dmaengine_terminate_all(prtd->dma_chan);
+ dmaengine_terminate_async(prtd->dma_chan);
break;
default:
return -EINVAL;
@@ -346,6 +346,7 @@ int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
{
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+ dmaengine_synchronize(prtd->dma_chan);
kfree(prtd);
return 0;
@@ -362,9 +363,11 @@ int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream)
{
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+ dmaengine_synchronize(prtd->dma_chan);
dma_release_channel(prtd->dma_chan);
+ kfree(prtd);
- return snd_dmaengine_pcm_close(substream);
+ return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close_release_chan);
--
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