From: Xin Xiong <xiongx18@fudan.edu.cn>
To: Ulf Hansson <ulf.hansson@linaro.org>,
linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: yuanxzhang@fudan.edu.cn, Xin Xiong <xiongx18@fudan.edu.cn>,
Xiyu Yang <xiyuyang19@fudan.edu.cn>,
Xin Tan <tanxin.ctf@gmail.com>
Subject: [PATCH v4] drivers/mmc: fix reference count leaks in moxart_probe
Date: Sat, 9 Oct 2021 12:19:18 +0800 [thread overview]
Message-ID: <20211009041918.28419-1-xiongx18@fudan.edu.cn> (raw)
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>
---
drivers/mmc/host/moxart-mmc.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c
index 6c9d38132..7b9fcef49 100644
--- a/drivers/mmc/host/moxart-mmc.c
+++ b/drivers/mmc/host/moxart-mmc.c
@@ -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);
--
2.25.1
next reply other threads:[~2021-10-09 4:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-09 4:19 Xin Xiong [this message]
2021-10-12 8:27 ` [PATCH v4] drivers/mmc: fix reference count leaks in moxart_probe Ulf Hansson
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