This is a note to let you know that I've just added the patch titled ASoC: fsl_asrc_dma: fix potential null-ptr-deref to the 6.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: asoc-fsl_asrc_dma-fix-potential-null-ptr-deref.patch and it can be found in the queue-6.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 86a24e99c97234f87d9f70b528a691150e145197 Mon Sep 17 00:00:00 2001 From: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx> Date: Mon, 17 Apr 2023 06:32:42 -0700 Subject: ASoC: fsl_asrc_dma: fix potential null-ptr-deref From: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx> 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@xxxxxxxxxx> Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx> Acked-by: Shengjiu Wang <shengjiu.wang@xxxxxxxxx> Link: https://lore.kernel.org/r/20230417133242.53339-1-n.zhandarovich@xxxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -209,14 +209,19 @@ 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 */ Patches currently in stable-queue which might be from n.zhandarovich@xxxxxxxxxx are queue-6.2/asoc-fsl_asrc_dma-fix-potential-null-ptr-deref.patch queue-6.2/mlxfw-fix-null-ptr-deref-in-mlxfw_mfa2_tlv_next.patch