From: Ross Zwisler zwisler@chromium.org
commit 0efa3334d65b7f421ba12382dfa58f6ff5bf83c4 upstream.
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 Signed-off-by: Mark Brown broonie@kernel.org ---
The upstream patch applied cleanly to all stable trees except linux-4.4.y and linux-3.18.y. This is the backport for linux-4.4.y, and the code I'm fixing was introduced in v4.0 so there is no need for a linux-3.18.y backport.
The upstream patch is currently in Mark Brown's tree:
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/log/?h=for...
Is that good enough, or should I resend after it's been merged in the v5.2 merge window?
--- sound/soc/intel/common/sst-dsp.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/sound/soc/intel/common/sst-dsp.c b/sound/soc/intel/common/sst-dsp.c index c9452e02e0dda..c0a50ecb6dbda 100644 --- a/sound/soc/intel/common/sst-dsp.c +++ b/sound/soc/intel/common/sst-dsp.c @@ -463,11 +463,15 @@ 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);