From: Nikita Zhandarovich n.zhandarovich@fintech.ru
commit 86a24e99c97234f87d9f70b528a691150e145197 upstream.
dma_request_slave_channel() may return NULL which will lead to NULL pointer dereference error in 'tmp_chan->private'.
Correct this behaviour by, first, switching from deprecated function dma_request_slave_channel() to dma_request_chan(). Secondly, enable sanity check for the resuling value of dma_request_chan(). Also, fix description that follows the enacted changes and that concerns the use of dma_request_slave_channel().
Fixes: 706e2c881158 ("ASoC: fsl_asrc_dma: Reuse the dma channel if available in Back-End") Co-developed-by: Natalia Petrova n.petrova@fintech.ru Signed-off-by: Nikita Zhandarovich n.zhandarovich@fintech.ru Acked-by: Shengjiu Wang shengjiu.wang@gmail.com Link: https://lore.kernel.org/r/20230417133242.53339-1-n.zhandarovich@fintech.ru Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- sound/soc/fsl/fsl_asrc_dma.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
--- a/sound/soc/fsl/fsl_asrc_dma.c +++ b/sound/soc/fsl/fsl_asrc_dma.c @@ -208,14 +208,19 @@ static int fsl_asrc_dma_hw_params(struct be_chan = soc_component_to_pcm(component_be)->chan[substream->stream]; tmp_chan = be_chan; } - if (!tmp_chan) - tmp_chan = dma_request_slave_channel(dev_be, tx ? "tx" : "rx"); + if (!tmp_chan) { + tmp_chan = dma_request_chan(dev_be, tx ? "tx" : "rx"); + if (IS_ERR(tmp_chan)) { + dev_err(dev, "failed to request DMA channel for Back-End\n"); + return -EINVAL; + } + }
/* * An EDMA DEV_TO_DEV channel is fixed and bound with DMA event of each * peripheral, unlike SDMA channel that is allocated dynamically. So no * need to configure dma_request and dma_request2, but get dma_chan of - * Back-End device directly via dma_request_slave_channel. + * Back-End device directly via dma_request_chan. */ if (!asrc->use_edma) { /* Get DMA request of Back-End */