[PATCH 5.11 29/41] dmaengine: xilinx: dpdma: Fix race condition in done IRQ

[Greg Kroah-Hartman]

From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>

[ Upstream commit 868833fbffbe51c487df4f95d4de9194264a4b30 ]

The active descriptor pointer is accessed from different contexts,
including different interrupt handlers, and its access must be protected
by the channel's lock. This wasn't done in the done IRQ handler. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210307040629.29308-3-laurent.pinchart@xxxxxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/dma/xilinx/xilinx_dpdma.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
index d504112c609e..70b29bd079c9 100644
--- a/drivers/dma/xilinx/xilinx_dpdma.c
+++ b/drivers/dma/xilinx/xilinx_dpdma.c
@@ -1048,13 +1048,14 @@ static int xilinx_dpdma_chan_stop(struct xilinx_dpdma_chan *chan)
  */
 static void xilinx_dpdma_chan_done_irq(struct xilinx_dpdma_chan *chan)
 {
-	struct xilinx_dpdma_tx_desc *active = chan->desc.active;
+	struct xilinx_dpdma_tx_desc *active;
 	unsigned long flags;
 
 	spin_lock_irqsave(&chan->lock, flags);
 
 	xilinx_dpdma_debugfs_desc_done_irq(chan);
 
+	active = chan->desc.active;
 	if (active)
 		vchan_cyclic_callback(&active->vdesc);
 	else
-- 
2.30.2