[PATCH] dmaengine: sprd: Fix runtime PM reference leak in probe

[Ruoyu Wang]

pm_runtime_get_sync() increments a device's usage counter even when it
fails. sprd_dma_probe() currently jumps directly to controller clock
cleanup on that error, bypassing both pm_runtime_put_noidle() and
pm_runtime_disable(). This can happen if the preceding unchecked
pm_runtime_set_active() fails and the following runtime-resume attempt
also returns an error.

Enter the existing runtime-PM unwind path instead. This drops the
reference without idling the partially initialized device, disables
runtime PM, and then releases the controller clocks. The success path
and propagated error code are unchanged.

This issue was found by a static analysis checker and confirmed by manual
source review.

Fixes: 9b3b8171f7f4 ("dmaengine: sprd: Add Spreadtrum DMA driver")
Signed-off-by: Ruoyu Wang <ruoyuw560@xxxxxxxxx>
---
 drivers/dma/sprd-dma.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index 087fea3af2e411..19b32a23c882de 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -1212,7 +1212,7 @@ static int sprd_dma_probe(struct platform_device *pdev)
 
 	ret = pm_runtime_get_sync(&pdev->dev);
 	if (ret < 0)
-		goto err_rpm;
+		goto err_register;
 
 	ret = dma_async_device_register(&sdev->dma_dev);
 	if (ret < 0) {
@@ -1234,7 +1234,6 @@ static int sprd_dma_probe(struct platform_device *pdev)
 err_register:
 	pm_runtime_put_noidle(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-err_rpm:
 	sprd_dma_disable(sdev);
 	return ret;
 }
-- 
2.51.0