From: Xiyu Yang <xiyuyang19@fudan.edu.cn> To: Peter Ujfalusi <peter.ujfalusi@ti.com>, Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Cc: yuanxzhang@fudan.edu.cn, kjlu@umn.edu, Xiyu Yang <xiyuyang19@fudan.edu.cn>, Xin Tan <tanxin.ctf@gmail.com> Subject: [PATCH] ASoC: davinci-mcasp: Fix dma_chan refcnt leak when getting dma type Date: Sat, 25 Apr 2020 20:48:35 +0800 [thread overview] Message-ID: <1587818916-38730-1-git-send-email-xiyuyang19@fudan.edu.cn> (raw) davinci_mcasp_get_dma_type() invokes dma_request_chan(), which returns a reference of the specified dma_chan object to "chan" with increased refcnt. When davinci_mcasp_get_dma_type() returns, local variable "chan" becomes invalid, so the refcount should be decreased to keep refcount balanced. The reference counting issue happens in one exception handling path of davinci_mcasp_get_dma_type(). When chan device is NULL, the function forgets to decrease the refcnt increased by dma_request_chan(), causing a refcnt leak. Fix this issue by calling dma_release_channel() when chan device is NULL. Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> --- sound/soc/ti/davinci-mcasp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/sound/soc/ti/davinci-mcasp.c b/sound/soc/ti/davinci-mcasp.c index 734ffe925c4d..7a7db743dc5b 100644 --- a/sound/soc/ti/davinci-mcasp.c +++ b/sound/soc/ti/davinci-mcasp.c @@ -1896,8 +1896,10 @@ static int davinci_mcasp_get_dma_type(struct davinci_mcasp *mcasp) PTR_ERR(chan)); return PTR_ERR(chan); } - if (WARN_ON(!chan->device || !chan->device->dev)) + if (WARN_ON(!chan->device || !chan->device->dev)) { + dma_release_channel(chan); return -EINVAL; + } if (chan->device->dev->of_node) ret = of_property_read_string(chan->device->dev->of_node, -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: Xiyu Yang <xiyuyang19@fudan.edu.cn> To: Peter Ujfalusi <peter.ujfalusi@ti.com>, Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Cc: Xin Tan <tanxin.ctf@gmail.com>, yuanxzhang@fudan.edu.cn, kjlu@umn.edu, Xiyu Yang <xiyuyang19@fudan.edu.cn> Subject: [PATCH] ASoC: davinci-mcasp: Fix dma_chan refcnt leak when getting dma type Date: Sat, 25 Apr 2020 20:48:35 +0800 [thread overview] Message-ID: <1587818916-38730-1-git-send-email-xiyuyang19@fudan.edu.cn> (raw) davinci_mcasp_get_dma_type() invokes dma_request_chan(), which returns a reference of the specified dma_chan object to "chan" with increased refcnt. When davinci_mcasp_get_dma_type() returns, local variable "chan" becomes invalid, so the refcount should be decreased to keep refcount balanced. The reference counting issue happens in one exception handling path of davinci_mcasp_get_dma_type(). When chan device is NULL, the function forgets to decrease the refcnt increased by dma_request_chan(), causing a refcnt leak. Fix this issue by calling dma_release_channel() when chan device is NULL. Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> --- sound/soc/ti/davinci-mcasp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/sound/soc/ti/davinci-mcasp.c b/sound/soc/ti/davinci-mcasp.c index 734ffe925c4d..7a7db743dc5b 100644 --- a/sound/soc/ti/davinci-mcasp.c +++ b/sound/soc/ti/davinci-mcasp.c @@ -1896,8 +1896,10 @@ static int davinci_mcasp_get_dma_type(struct davinci_mcasp *mcasp) PTR_ERR(chan)); return PTR_ERR(chan); } - if (WARN_ON(!chan->device || !chan->device->dev)) + if (WARN_ON(!chan->device || !chan->device->dev)) { + dma_release_channel(chan); return -EINVAL; + } if (chan->device->dev->of_node) ret = of_property_read_string(chan->device->dev->of_node, -- 2.7.4
next reply other threads:[~2020-04-25 12:49 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-25 12:48 Xiyu Yang [this message] 2020-04-25 12:48 ` [PATCH] ASoC: davinci-mcasp: Fix dma_chan refcnt leak when getting dma type Xiyu Yang 2020-04-28 8:13 ` Peter Ujfalusi 2020-04-28 8:13 ` Peter Ujfalusi 2020-04-28 15:40 ` Mark Brown 2020-04-28 15:40 ` Mark Brown
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