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@xxxxxxxxx>
Reviewed-by: Ludovic BARRE <ludovic.barre@xxxxxx>
---
drivers/dma/stm32-dma.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index a884b85..3056ce7 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);
--
1.9.1
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