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mmc: moxart: Fix reference count leaks in moxart_probe

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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: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Link: https://lore.kernel.org/r/20211009041918.28419-1-xiongx18@fudan.edu.cn
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Xin Xiong 2021-10-09 12:19:18 +08:00 committed by Ulf Hansson
parent f83c18cc9e
commit 8105c2abbf
1 changed files with 14 additions and 2 deletions
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16
drivers/mmc/host/moxart-mmc.c
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@ -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);