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ASoC: Intel: avoid Oops if DMA setup fails

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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>
This commit is contained in:
Ross Zwisler 2019-04-29 12:25:17 -06:00 committed by Mark Brown
parent 726fc60bab
commit 0efa3334d6
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GPG Key ID: 24D68B725D5487D0
1 changed files with 6 additions and 2 deletions
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8
sound/soc/intel/common/sst-firmware.c
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@ -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);