dmaengine: sprd: Add validation of current descriptor in irq handler

When user terminates one DMA channel to free all its descriptors, but
at the same time one transaction interrupt was triggered possibly, now
we should not handle this interrupt by validating if the 'schan->cur_desc'
was set as NULL to avoid crashing the kernel.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index e29342ab85f687c71dbf0f2447c3057e67ef4f73..431e289d59a55ff4e22024b9d596ee7e32508a7b 100644 (file)
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -552,12 +552,17 @@ static irqreturn_t dma_irq_handle(int irq, void *dev_id)
                schan = &sdev->channels[i];
 
                spin_lock(&schan->vc.lock);
+
+               sdesc = schan->cur_desc;
+               if (!sdesc) {
+                       spin_unlock(&schan->vc.lock);
+                       return IRQ_HANDLED;
+               }
+
                int_type = sprd_dma_get_int_type(schan);
                req_type = sprd_dma_get_req_type(schan);
                sprd_dma_clear_int(schan);
 
-               sdesc = schan->cur_desc;
-
                /* cyclic mode schedule callback */
                cyclic = schan->linklist.phy_addr ? true : false;
                if (cyclic == true) {