From 57b5a32135c813f2ab669039fb4ec16b30cb3305 Mon Sep 17 00:00:00 2001 From: M'boumba Cedric Madianga Date: Tue, 13 Dec 2016 14:40:46 +0100 Subject: 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: M'boumba Cedric Madianga Reviewed-by: Ludovic BARRE Signed-off-by: Vinod Koul --- drivers/dma/stm32-dma.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) (limited to 'drivers/dma') diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index a884b857cba4..3056ce7f8c69 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -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); -- cgit v1.2.3-59-g8ed1b