From 0b6d055edb55ecadadf54e930c2b4fab76fa9a5a Mon Sep 17 00:00:00 2001 From: Suraj Gupta Date: Fri, 26 Jun 2026 14:56:54 +0530 Subject: [PATCH] dmaengine: xilinx_dma: Fix channel idle state management in AXIDMA and MCDMA interrupt handlers Fix a race condition in AXIDMA and MCDMA irq handlers where the channel could be incorrectly marked as idle and attempt spurious transfers when descriptors are still being processed. The issue occurs when: 1. Multiple descriptors are queued and active. 2. An interrupt fires after completing some descriptors. 3. xilinx_dma_complete_descriptor() moves completed descriptors to done_list. 4. Channel is marked idle and start_transfer() is called even though active_list still contains unprocessed descriptors. 5. This leads to premature transfer attempts and potential descriptor corruption or missed completions. Only mark the channel as idle and start new transfers when the active list is actually empty, ensuring proper channel state management and avoiding spurious transfer attempts. Fixes: c0bba3a99f07 ("dmaengine: vdma: Add Support for Xilinx AXI Direct Memory Access Engine") Tested-by: Folker Schwesinger Signed-off-by: Suraj Gupta Co-developed-by: Srinivas Neeli Signed-off-by: Srinivas Neeli Reviewed-by: Radhey Shyam Pandey Link: https://patch.msgid.link/20260626092656.1563871-2-suraj.gupta2@amd.com Signed-off-by: Vinod Koul --- drivers/dma/xilinx/xilinx_dma.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c index 404235c17353..ca396b709742 100644 --- a/drivers/dma/xilinx/xilinx_dma.c +++ b/drivers/dma/xilinx/xilinx_dma.c @@ -1893,8 +1893,10 @@ static irqreturn_t xilinx_mcdma_irq_handler(int irq, void *data) if (status & XILINX_MCDMA_IRQ_IOC_MASK) { spin_lock(&chan->lock); xilinx_dma_complete_descriptor(chan); - chan->idle = true; - chan->start_transfer(chan); + if (list_empty(&chan->active_list)) { + chan->idle = true; + chan->start_transfer(chan); + } spin_unlock(&chan->lock); } @@ -1950,8 +1952,10 @@ static irqreturn_t xilinx_dma_irq_handler(int irq, void *data) XILINX_DMA_DMASR_DLY_CNT_IRQ)) { spin_lock(&chan->lock); xilinx_dma_complete_descriptor(chan); - chan->idle = true; - chan->start_transfer(chan); + if (list_empty(&chan->active_list)) { + chan->idle = true; + chan->start_transfer(chan); + } spin_unlock(&chan->lock); }