Commit 8105c2ab authored by Xin Xiong's avatar Xin Xiong Committed by Ulf Hansson
Browse files

mmc: moxart: Fix reference count leaks in moxart_probe 



The issue happens in several error handling paths on two refcounted
object related to the object "host" (dma_chan_rx, dma_chan_tx). In
these paths, the function forgets to decrement one or both objects'
reference count increased earlier by dma_request_chan(), causing
reference count leaks.

Fix it by balancing the refcounts of both objects in some error
handling paths. In correspondence with the changes in moxart_probe(),
IS_ERR() is replaced with IS_ERR_OR_NULL() in moxart_remove() as well.

Signed-off-by: default avatarXin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: default avatarXiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: default avatarXin Tan <tanxin.ctf@gmail.com>
Link: https://lore.kernel.org/r/20211009041918.28419-1-xiongx18@fudan.edu.cn


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent f83c18cc

drivers/mmc/host/moxart-mmc.c

+14 −2
Original line number Diff line number Diff line
@@ -621,6 +621,14 @@ static int moxart_probe(struct platform_device *pdev) 
			ret = -EPROBE_DEFER;

			goto out;

		}

		if (!IS_ERR(host->dma_chan_tx)) {

			dma_release_channel(host->dma_chan_tx);

			host->dma_chan_tx = NULL;

		}

		if (!IS_ERR(host->dma_chan_rx)) {

			dma_release_channel(host->dma_chan_rx);

			host->dma_chan_rx = NULL;

		}

		dev_dbg(dev, "PIO mode transfer enabled\n");

		host->have_dma = false;

	} else {
@@ -675,6 +683,10 @@ static int moxart_probe(struct platform_device *pdev) 
	return 0;



out:

	if (!IS_ERR_OR_NULL(host->dma_chan_tx))

		dma_release_channel(host->dma_chan_tx);

	if (!IS_ERR_OR_NULL(host->dma_chan_rx))

		dma_release_channel(host->dma_chan_rx);

	if (mmc)

		mmc_free_host(mmc);

	return ret;
@@ -687,9 +699,9 @@ static int moxart_remove(struct platform_device *pdev) 


	dev_set_drvdata(&pdev->dev, NULL);



	if (!IS_ERR(host->dma_chan_tx))

	if (!IS_ERR_OR_NULL(host->dma_chan_tx))

		dma_release_channel(host->dma_chan_tx);

	if (!IS_ERR(host->dma_chan_rx))

	if (!IS_ERR_OR_NULL(host->dma_chan_rx))

		dma_release_channel(host->dma_chan_rx);

	mmc_remove_host(mmc);

	mmc_free_host(mmc);