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Date:   Mon, 29 Apr 2019 12:25:17 -0600
From:   Ross Zwisler <>
To:     Pierre-Louis Bossart <>,
Cc:     Ross Zwisler <>,
        Jaroslav Kysela <>,
        Jie Yang <>,
        Liam Girdwood <>,
        Mark Brown <>, Takashi Iwai <>,,
Subject: [PATCH v2] ASoC: Intel: avoid Oops if DMA setup fails

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

        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 <>

Changes in v2:
 - Upgraded the sst_dma_new() failure message from dev_warn() to dev_err()
 - 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;
+	free_irq(sst->irq, sst);
 	if (sst->ops->free)

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