linux-kernel - Re: [PATCH] media: hantro: Fix PM reference leak in device

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Date:   Mon, 17 May 2021 20:35:47 +0800
From:   "yukuai (C)" <yukuai3@...wei.com>
To:     Johan Hovold <johan@...nel.org>
CC:     <ezequiel@...labora.com>, <p.zabel@...gutronix.de>,
        <mchehab@...nel.org>, <gregkh@...uxfoundation.org>,
        <linux-media@...r.kernel.org>,
        <linux-rockchip@...ts.infradead.org>,
        <linux-staging@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
        <yi.zhang@...wei.com>
Subject: Re: [PATCH] media: hantro: Fix PM reference leak in device_run()

On 2021/05/17 16:22, Johan Hovold wrote:
> On Mon, May 17, 2021 at 04:15:16PM +0800, 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/staging/media/hantro/hantro_drv.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/media/hantro/hantro_drv.c
>> index eea2009fa17b..7a6d3ef22096 100644
>> --- a/drivers/staging/media/hantro/hantro_drv.c
>> +++ b/drivers/staging/media/hantro/hantro_drv.c
>> @@ -160,7 +160,7 @@ static void device_run(void *priv)
>>   	src = hantro_get_src_buf(ctx);
>>   	dst = hantro_get_dst_buf(ctx);
>>   
>> -	ret = pm_runtime_get_sync(ctx->dev->dev);
>> +	ret = pm_runtime_resume_and_get(ctx->dev->dev);
>>   	if (ret < 0) {
>>   		pm_runtime_put_noidle(ctx->dev->dev);
> 
> This is clearly broken as there is no PM usage count leak here.
> 
> Please try to understand the code you're changing before submitting any
> more patches based on "robot" feedback.

Hi,

Sorry about the mistake, and thank you very much for your explanation

Yu Kuai
> 
>>   		goto err_cancel_job;
> 
> Johan
> .
>