On 4/29/19 1:25 PM, Ross Zwisler wrote:
Currently in sst_dsp_new() if we get an error return from sst_dma_new() we just print an error message and then still complete the function successfully. This means that we are trying to run without sst->dma properly set up, which will result in NULL pointer dereference when sst->dma is later used. This was happening for me in sst_dsp_dma_get_channel():
struct sst_dma *dma = dsp->dma;... dma->ch = dma_request_channel(mask, dma_chan_filter, dsp);
This resulted in:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: sst_dsp_dma_get_channel+0x4f/0x125 [snd_soc_sst_firmware]Fix this by adding proper error handling for the case where we fail to set up DMA.
This change only affects Haswell and Broadwell systems. Baytrail systems explicilty opt-out of DMA via sst->pdata->resindex_dma_base being set to -1.
Signed-off-by: Ross Zwisler zwisler@google.com Cc: stable@vger.kernel.org
Acked-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com
Thanks Ross!
FWIW we should start deprecating this driver now and transition to SOF. I'll double-check how the upcoming 1.3 release works on my Pixel 2015/Samus device later this week.
Changes in v2:
- Upgraded the sst_dma_new() failure message from dev_warn() to dev_err() (Pierre-Louis).
- Noted in the changelog that this change only affects Haswell and Broadwell (Pierre-Louis).
sound/soc/intel/common/sst-firmware.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/sound/soc/intel/common/sst-firmware.c b/sound/soc/intel/common/sst-firmware.c index 1e067504b6043..f830e59f93eaa 100644 --- a/sound/soc/intel/common/sst-firmware.c +++ b/sound/soc/intel/common/sst-firmware.c @@ -1251,11 +1251,15 @@ struct sst_dsp *sst_dsp_new(struct device *dev, goto irq_err;
err = sst_dma_new(sst);
- if (err)
dev_warn(dev, "sst_dma_new failed %d\n", err);
if (err) {
dev_err(dev, "sst_dma_new failed %d\n", err);goto dma_err;}
return sst;
+dma_err:
- free_irq(sst->irq, sst); irq_err: if (sst->ops->free) sst->ops->free(sst);