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dmaengine: fsl-edma: check channel acquisition before use

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dma_get_slave_channel() can return NULL when acquiring a channel fails,
for example if fsl_edma_alloc_chan_resources() cannot request an IRQ.
fsl_edma3_xlate() dereferences that return value to update privatecnt.

Acquire and check the channel before publishing its source ID and
request parameters. A NULL-only check after the existing source-ID
assignment would leave the failed request marked as in use, causing
fsl_edma_srcid_in_use() to reject a subsequent request for that source.
The channel resource-allocation callback does not consume these request
parameters, so set them only after acquisition succeeds. The existing
scoped mutex release and successful-channel return are preserved.

Detected by static analysis and reviewed with AI-assisted source auditing.

Assisted-by: LLM
Signed-off-by: Slavin Liu <bolin.liu@seu.edu.cn>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260911060902.94153-1-bolin.liu@seu.edu.cn
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Slavin Liu 2026-09-11 14:09:02 +08:00 committed by Vinod Koul
parent 32ac4723e5
commit bfd958664f
1 changed files with 4 additions and 1 deletions
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5
drivers/dma/fsl-edma-main.c
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@ -326,13 +326,16 @@ static struct dma_chan *fsl_edma3_xlate(struct of_phandle_args *dma_spec,
if ((dma_spec->args[2] & FSL_EDMA_ODD_CH) && !(i & 0x1))
continue;
chan = dma_get_slave_channel(chan);
if (!chan)
return NULL;
fsl_chan->srcid = dma_spec->args[0];
fsl_chan->priority = dma_spec->args[1];
fsl_chan->is_rxchan = dma_spec->args[2] & FSL_EDMA_RX;
fsl_chan->is_remote = dma_spec->args[2] & FSL_EDMA_REMOTE;
fsl_chan->is_multi_fifo = dma_spec->args[2] & FSL_EDMA_MULTI_FIFO;
chan = dma_get_slave_channel(chan);
chan->device->privatecnt++;
return chan;
}