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);- }
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
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