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>
diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c
index fba365a..697c166 100644
--- a/sound/core/pcm_dmaengine.c
+++ b/sound/core/pcm_dmaengine.c
@@ -202,13 +202,13 @@
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 @@
{
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+ dmaengine_synchronize(prtd->dma_chan);
kfree(prtd);
return 0;
@@ -362,9 +363,11 @@
{
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);