dmaengine: stm32-dma: Fix null pointer dereference in stm32_dma_tx_status (57b5a321) · Commits · 戴 / test

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:

M'boumba Cedric Madianga <cedric.madianga@gmail.com> Reviewed-by:

Ludovic BARRE <ludovic.barre@st.com> Signed-off-by:

Vinod Koul <vinod.koul@intel.com>

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);

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