From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Xiyu Yang <xiyuyang19@fudan.edu.cn>,
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>,
Xin Tan <tanxin.ctf@gmail.com>
Subject: Re: [PATCH] ASoC: davinci-mcasp: Fix dma_chan refcnt leak when getting dma type
Date: Tue, 28 Apr 2020 11:13:15 +0300 [thread overview]
Message-ID: <a64cfa62-c377-b516-7386-23340e532285@ti.com> (raw)
In-Reply-To: <1587818916-38730-1-git-send-email-xiyuyang19@fudan.edu.cn>
On 25/04/2020 15.48, Xiyu Yang wrote:
> 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 we get a channel then chan->device and chan->device->dev never NULL,
it can not be.
I think the reason why this is here is that static checkers tends to
scream at us.
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>
> if (chan->device->dev->of_node)
> ret = of_property_read_string(chan->device->dev->of_node,
>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
WARNING: multiple messages have this Message-ID (diff)
From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Xiyu Yang <xiyuyang19@fudan.edu.cn>,
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
Subject: Re: [PATCH] ASoC: davinci-mcasp: Fix dma_chan refcnt leak when getting dma type
Date: Tue, 28 Apr 2020 11:13:15 +0300 [thread overview]
Message-ID: <a64cfa62-c377-b516-7386-23340e532285@ti.com> (raw)
In-Reply-To: <1587818916-38730-1-git-send-email-xiyuyang19@fudan.edu.cn>
On 25/04/2020 15.48, Xiyu Yang wrote:
> 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 we get a channel then chan->device and chan->device->dev never NULL,
it can not be.
I think the reason why this is here is that static checkers tends to
scream at us.
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>
> if (chan->device->dev->of_node)
> ret = of_property_read_string(chan->device->dev->of_node,
>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
next prev parent reply other threads:[~2020-04-28 8:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-25 12:48 [PATCH] ASoC: davinci-mcasp: Fix dma_chan refcnt leak when getting dma type Xiyu Yang
2020-04-25 12:48 ` Xiyu Yang
2020-04-28 8:13 ` Peter Ujfalusi [this message]
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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