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Commit 6fee3987 authored by Ross Zwisler's avatar Ross Zwisler Committed by Greg Kroah-Hartman
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ASoC: Intel: avoid Oops if DMA setup fails 



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: default avatarRoss Zwisler <zwisler@google.com>
Cc: stable@vger.kernel.org
Acked-by: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c3b3955f

sound/soc/intel/common/sst-firmware.c

+6 −2
Original line number Diff line number Diff line
@@ -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);