chan->desc can be null, if transfer is terminated when resume is called, leading to a NULL pointer when retrieving the hwdesc. To avoid this case, check that chan->desc is not null and channel is disabled (transfer previously paused or terminated).
Fixes: a4ffb13c8946 ("dmaengine: Add STM32 MDMA driver") Signed-off-by: Amelie Delaunay amelie.delaunay@foss.st.com Cc: stable@vger.kernel.org --- drivers/dma/stm32-mdma.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c index 0de234022c6d..cc6f4b00091f 100644 --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -1236,6 +1236,10 @@ static int stm32_mdma_resume(struct dma_chan *c) unsigned long flags; u32 status, reg;
+ /* Transfer can be terminated */ + if (!chan->desc || (stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)) & STM32_MDMA_CCR_EN)) + return -EPERM; + hwdesc = chan->desc->node[chan->curr_hwdesc].hwdesc;
spin_lock_irqsave(&chan->vchan.lock, flags);