linux-kernel - Re: [PATCH 2/3] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac

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Message-ID: <YLRfZfnuxc0+n/LN@vkoul-mobl.Dlink>
Date:   Mon, 31 May 2021 09:30:37 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Yu Kuai <yukuai3@...wei.com>
Cc:     mcoquelin.stm32@...il.com, alexandre.torgue@...s.st.com,
        michal.simek@...inx.com, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org, yi.zhang@...wei.com
Subject: Re: [PATCH 2/3] dmaengine: usb-dmac: Fix PM reference leak in
 usb_dmac_probe()

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@...wei.com>
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> ---
>  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

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

-- 
~Vinod