linux-kernel - [PATCH] drivers/dma: fix reference count leaks in mmp_pdma

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Message-Id: <20210911070533.3114-1-xiongx18@fudan.edu.cn>
Date:   Sat, 11 Sep 2021 15:05:33 +0800
From:   Xin Xiong <xiongx18@...an.edu.cn>
To:     Vinod Koul <vkoul@...nel.org>, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     yuanxzhang@...an.edu.cn, Xin Xiong <xiongx18@...an.edu.cn>,
        Xiyu Yang <xiyuyang19@...an.edu.cn>,
        Xin Tan <tanxin.ctf@...il.com>
Subject: [PATCH] drivers/dma: fix reference count leaks in mmp_pdma_probe

The issue happens in an error handling path. If
of_dma_controller_register() fails, the function simply prints error
messages and returns error code, without decrementing the reference
count of pdev->device incremented earlier by
dma_async_device_register(), which may result in refcount leaks.

Fix it by invoking dma_async_device_unregister() before returning the
error code.

Signed-off-by: Xin Xiong <xiongx18@...an.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@...an.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@...il.com>
---
 drivers/dma/mmp_pdma.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c
index 89f1814ff..a23563cd1 100644
--- a/drivers/dma/mmp_pdma.c
+++ b/drivers/dma/mmp_pdma.c
@@ -1123,6 +1123,7 @@ static int mmp_pdma_probe(struct platform_device *op)
 						 mmp_pdma_dma_xlate, pdev);
 		if (ret < 0) {
 			dev_err(&op->dev, "of_dma_controller_register failed\n");
+			dma_async_device_unregister(&pdev->device);
 			return ret;
 		}
 	}
-- 
2.25.1