[PATCH v2] mtd: rawnand: gpmi: terminate the DMA chain on completion timeout

[Samarth Narang <samarth.colleges@gmail.com>]

When DMA completion times out in gpmi_nfc_exec_op(), the driver unmaps
the operation's buffers and returns -ETIMEDOUT without stopping the APBH
DMA channel. Since mxs-dma leaves the channel in DMA_IN_PROGRESS, the
pending descriptor chain may resume after the timeout, while a
subsequent operation can append new descriptors to the stale chain and
cause the old DATA_IN transfer to execute again against an unmapped
buffer.

This can result in DMA writes to memory that has already been released,
including buffers freed after ONFI parameter page detection in
nand_onfi_detect().

Terminate the channel with dmaengine_terminate_sync() before unmapping
so that outstanding transfers are stopped and subsequent operations
begin with a fresh descriptor chain.

Fixes: ef347c0cfd61 ("mtd: rawnand: gpmi: Implement exec_op")
Assisted-by: LLM
Signed-off-by: Samarth Narang <samarth.colleges@gmail.com>
---
Changes in v2:
- Drop the code comment

v1: https://lore.kernel.org/all/20261030143945.2923554-1-samarth.colleges@gmail.com/

This issue was identified by a research static analyzer for DMA
lifecycle ordering and has not been validated on hardware.
Compile-tested only.

 drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
index 527165ccc..a8106de2c 100644
--- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
@@ -2659,6 +2659,7 @@ static int gpmi_nfc_exec_op(struct nand_chip *chip,
 	if (!to) {
 		dev_err(this->dev, "DMA timeout, last DMA\n");
 		gpmi_dump_info(this);
+		dmaengine_terminate_sync(get_dma_chan(this));
 		ret = -ETIMEDOUT;
 		goto unmap;
 	}

base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907