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Commit 57b5a321 authored by M'boumba Cedric Madianga's avatar M'boumba Cedric Madianga Committed by Vinod Koul
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dmaengine: stm32-dma: Fix null pointer dereference in stm32_dma_tx_status 



chan->desc is always set to NULL when a DMA transfer is complete.
As a DMA transfer could be complete during the call of stm32_dma_tx_status,
we need to be sure that chan->desc is not NULL before using this variable
to avoid a null pointer deference issue.

Signed-off-by: default avatarM'boumba Cedric Madianga <cedric.madianga@gmail.com>
Reviewed-by: default avatarLudovic BARRE <ludovic.barre@st.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 7e96304d

drivers/dma/stm32-dma.c

+3 −7
Original line number Diff line number Diff line
@@ -880,7 +880,7 @@ static enum dma_status stm32_dma_tx_status(struct dma_chan *c, 
	struct virt_dma_desc *vdesc;

	enum dma_status status;

	unsigned long flags;

	u32 residue;

	u32 residue = 0;



	status = dma_cookie_status(c, cookie, state);

	if ((status == DMA_COMPLETE) || (!state))
@@ -888,16 +888,12 @@ static enum dma_status stm32_dma_tx_status(struct dma_chan *c, 


	spin_lock_irqsave(&chan->vchan.lock, flags);

	vdesc = vchan_find_desc(&chan->vchan, cookie);

	if (cookie == chan->desc->vdesc.tx.cookie) {

	if (chan->desc && cookie == chan->desc->vdesc.tx.cookie)

		residue = stm32_dma_desc_residue(chan, chan->desc,

						 chan->next_sg);

	} else if (vdesc) {

	else if (vdesc)

		residue = stm32_dma_desc_residue(chan,

						 to_stm32_dma_desc(vdesc), 0);

	} else {

		residue = 0;

	}



	dma_set_residue(state, residue);



	spin_unlock_irqrestore(&chan->vchan.lock, flags);