linux-kernel - Re: [PATCH 5/8] i2c: omap: fix reference leak when pm_runtime_get

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Date:   Wed, 2 Dec 2020 10:43:55 +0530
From:   Vignesh Raghavendra <vigneshr@...com>
To:     Qinglang Miao <miaoqinglang@...wei.com>,
        Aaro Koskinen <aaro.koskinen@....fi>,
        Tony Lindgren <tony@...mide.com>
CC:     <linux-omap@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/8] i2c: omap: fix reference leak when
 pm_runtime_get_sync fails



On 12/1/20 3:01 PM, Qinglang Miao wrote:
> The PM reference count is not expected to be incremented on
> return in omap_i2c_probe() and omap_i2c_remove().
> 
> However, pm_runtime_get_sync will increment the PM reference
> count even failed. Forgetting to putting operation will result
> in a reference leak here. I Replace it with pm_runtime_resume_and_get
> to keep usage counter balanced.
> 
> What's more, error path 'err_free_mem' seems not like a proper
> name any more. So I change the name to err_disable_pm and move
> pm_runtime_disable below, for pm_runtime of 'pdev->dev' should
> be disabled when pm_runtime_resume_and_get fails.
> 
> Fixes: 3b0fb97c8dc4 ("I2C: OMAP: Handle error check for pm runtime")
> Reported-by: Hulk Robot <hulkci@...wei.com>
> Signed-off-by: Qinglang Miao <miaoqinglang@...wei.com>
> ---

Reviewed-by: Vignesh Raghavendra <vigneshr@...com>

>  drivers/i2c/busses/i2c-omap.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 12ac4212a..d4f6c6d60 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -1404,9 +1404,9 @@ omap_i2c_probe(struct platform_device *pdev)
>  	pm_runtime_set_autosuspend_delay(omap->dev, OMAP_I2C_PM_TIMEOUT);
>  	pm_runtime_use_autosuspend(omap->dev);
>  
> -	r = pm_runtime_get_sync(omap->dev);
> +	r = pm_runtime_resume_and_get(omap->dev);
>  	if (r < 0)
> -		goto err_free_mem;
> +		goto err_disable_pm;
>  
>  	/*
>  	 * Read the Rev hi bit-[15:14] ie scheme this is 1 indicates ver2.
> @@ -1513,8 +1513,8 @@ omap_i2c_probe(struct platform_device *pdev)
>  	omap_i2c_write_reg(omap, OMAP_I2C_CON_REG, 0);
>  	pm_runtime_dont_use_autosuspend(omap->dev);
>  	pm_runtime_put_sync(omap->dev);
> +err_disable_pm:
>  	pm_runtime_disable(&pdev->dev);
> -err_free_mem:
>  
>  	return r;
>  }
> @@ -1525,7 +1525,7 @@ static int omap_i2c_remove(struct platform_device *pdev)
>  	int ret;
>  
>  	i2c_del_adapter(&omap->adapter);
> -	ret = pm_runtime_get_sync(&pdev->dev);
> +	ret = pm_runtime_resume_and_get(&pdev->dev);
>  	if (ret < 0)
>  		return ret;
>  
>