On Tue, 20 Oct 2015 11:46:31 +0200, Lars-Peter Clausen wrote: > > 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.
What if a substream is restarted immediately after the stop? Takashi > > Signed-off-by: Lars-Peter Clausen <[email protected]> > --- > sound/core/pcm_dmaengine.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > 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 @@ 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); > > -- > 2.1.4 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
