Commit aea08a5d authored Dec 07, 2015 by M'boumba Cedric Madianga Committed by Vinod Koul Dec 10, 2015

dmaengine: stm32-dma: Fix unchecked deference of chan->desc



'commit d8b46839 ("dmaengine: Add STM32 DMA driver")' leads to the
following Smatch complaint:

drivers/dma/stm32-dma.c:562 stm32_dma_issue_pending()
    error: we previously assumed 'chan->desc' could be null (see line 560)

So, this patch fixes the unchecked dereference of chan->desc by returning
operation not permitted error when stm32_dma_start_transfer() does not
succeed to allocate a virtual channel descriptor.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

parent b341b4a1

drivers/dma/stm32-dma.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -437,7 +437,7 @@ static int stm32_dma_start_transfer(struct stm32_dma_chan *chan)
		if (!chan->desc) {
		vdesc = vchan_next_desc(&chan->vchan);
		if (!vdesc)
		return 0;
		return -EPERM;

		chan->desc = to_stm32_dma_desc(vdesc);
		chan->next_sg = 0;
		@@ -559,7 +559,7 @@ static void stm32_dma_issue_pending(struct dma_chan *c)
		if (!chan->busy) {
		if (vchan_issue_pending(&chan->vchan) && !chan->desc) {
		ret = stm32_dma_start_transfer(chan);
		if ((chan->desc->cyclic) && (!ret))
		if ((!ret) && (chan->desc->cyclic))
		stm32_dma_configure_next_sg(chan);
		}
		}

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