Re: [PATCH 2/3] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe()

[yukuai (C)]

On 2021/05/31 12:00, Vinod Koul wrote:
> On 17-05-21, 16:18, Yu Kuai wrote:
> > pm_runtime_get_sync will increment pm usage counter even it failed.
> > Forgetting to putting operation will result in reference leak here.
> > Fix it by replacing it with pm_runtime_resume_and_get to keep usage
> > counter balanced.
> >
> > Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> > Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> > ---
> >   drivers/dma/sh/usb-dmac.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/dma/sh/usb-dmac.c b/drivers/dma/sh/usb-dmac.c
> > index 8f7ceb698226..2a6c8fd8854e 100644
> > --- a/drivers/dma/sh/usb-dmac.c
> > +++ b/drivers/dma/sh/usb-dmac.c
> > @@ -796,7 +796,7 @@ static int usb_dmac_probe(struct platform_device *pdev)
> >   
> >   	/* Enable runtime PM and initialize the device. */
> >   	pm_runtime_enable(&pdev->dev);
> > -	ret = pm_runtime_get_sync(&pdev->dev);
> > +	ret = pm_runtime_resume_and_get(&pdev->dev);
>
> This does not seem to fix anything.. the below goto goes and disables
> the runtime_pm for this device and thus there wont be any leak
Hi,

If pm_runtime_get_sync() fails and increments the pm.usage_count
variable, pm_runtime_disable() does not reset the counter, and
we still need to decrement the usage count when pm_runtime_get_sync()
fails. Do I miss anthing?

Thansk!
Yu Kuai
> >   	if (ret < 0) {
> >   		dev_err(&pdev->dev, "runtime PM get sync failed (%d)\n", ret);
> >   		goto error_pm;
> > --
> > 2.25.4