[PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()

[PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()

[Zou Wei]

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@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
---
 drivers/pwm/pwm-img.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
index cc37054..11b16ec 100644
--- a/drivers/pwm/pwm-img.c
+++ b/drivers/pwm/pwm-img.c
@@ -156,7 +156,7 @@ static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 	struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
 	int ret;
 
-	ret = pm_runtime_get_sync(chip->dev);
+	ret = pm_runtime_resume_and_get(chip->dev);
 	if (ret < 0)
 		return ret;
 
-- 
2.6.2

Re: [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()

[Uwe Kleine-König]

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Hello,

On Wed, May 12, 2021 at 11:57:17AM +0800, Zou Wei 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@huawei.com>
> Signed-off-by: Zou Wei <zou_wei@huawei.com>
> ---
>  drivers/pwm/pwm-img.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
> index cc37054..11b16ec 100644
> --- a/drivers/pwm/pwm-img.c
> +++ b/drivers/pwm/pwm-img.c
> @@ -156,7 +156,7 @@ static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>  	struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
>  	int ret;
>  
> -	ret = pm_runtime_get_sync(chip->dev);
> +	ret = pm_runtime_resume_and_get(chip->dev);
>  	if (ret < 0)
>  		return ret;

This patch looks right with my limited understanding of pm_runtime. A
similar issue in this driver was fixed in commit

	ca162ce98110 ("pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case")

where (even though the commit log talks about pm_runtime_put()) a call
to pm_runtime_put_autosuspend() was added in the error path.

I added the PM guys to Cc, maybe they can advise about the right thing
to do here. Does it make sense to use the same idiom in both
img_pwm_enable() and img_pwm_config()?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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Re: [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()

[Uwe Kleine-König]

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Hello Rafael, Kevin and Ulf,

On Wed, May 12, 2021 at 06:52:22AM +0200, Uwe Kleine-König wrote:
> Hello,
> 
> On Wed, May 12, 2021 at 11:57:17AM +0800, Zou Wei 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@huawei.com>
> > Signed-off-by: Zou Wei <zou_wei@huawei.com>
> > ---
> >  drivers/pwm/pwm-img.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
> > index cc37054..11b16ec 100644
> > --- a/drivers/pwm/pwm-img.c
> > +++ b/drivers/pwm/pwm-img.c
> > @@ -156,7 +156,7 @@ static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> >  	struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
> >  	int ret;
> >  
> > -	ret = pm_runtime_get_sync(chip->dev);
> > +	ret = pm_runtime_resume_and_get(chip->dev);
> >  	if (ret < 0)
> >  		return ret;
> 
> This patch looks right with my limited understanding of pm_runtime. A
> similar issue in this driver was fixed in commit
> 
> 	ca162ce98110 ("pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case")
> 
> where (even though the commit log talks about pm_runtime_put()) a call
> to pm_runtime_put_autosuspend() was added in the error path.
> 
> I added the PM guys to Cc, maybe they can advise about the right thing
> to do here. Does it make sense to use the same idiom in both
> img_pwm_enable() and img_pwm_config()?

Can you give some feedback here?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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Re: [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()

[Rafael J. Wysocki]

On Wed, May 12, 2021 at 6:52 AM Uwe Kleine-König
<u.kleine-koenig@pengutronix.de> wrote:
>
> Hello,
>
> On Wed, May 12, 2021 at 11:57:17AM +0800, Zou Wei 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@huawei.com>
> > Signed-off-by: Zou Wei <zou_wei@huawei.com>
> > ---
> >  drivers/pwm/pwm-img.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
> > index cc37054..11b16ec 100644
> > --- a/drivers/pwm/pwm-img.c
> > +++ b/drivers/pwm/pwm-img.c
> > @@ -156,7 +156,7 @@ static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> >       struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
> >       int ret;
> >
> > -     ret = pm_runtime_get_sync(chip->dev);
> > +     ret = pm_runtime_resume_and_get(chip->dev);
> >       if (ret < 0)
> >               return ret;
>
> This patch looks right with my limited understanding of pm_runtime. A
> similar issue in this driver was fixed in commit
>
>         ca162ce98110 ("pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case")
>
> where (even though the commit log talks about pm_runtime_put()) a call
> to pm_runtime_put_autosuspend() was added in the error path.
>
> I added the PM guys to Cc, maybe they can advise about the right thing
> to do here. Does it make sense to use the same idiom in both
> img_pwm_enable() and img_pwm_config()?

I think so.

And calling pm_runtime_put_autosuspend() in the img_pwm_enable() error
path would work too.

Re: [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()

[Uwe Kleine-König]

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Hello Zou,

On Fri, Jun 25, 2021 at 07:45:14PM +0200, Rafael J. Wysocki wrote:
> On Wed, May 12, 2021 at 6:52 AM Uwe Kleine-König
> <u.kleine-koenig@pengutronix.de> wrote:
> > On Wed, May 12, 2021 at 11:57:17AM +0800, Zou Wei 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@huawei.com>
> > > Signed-off-by: Zou Wei <zou_wei@huawei.com>
> > > ---
> > >  drivers/pwm/pwm-img.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
> > > index cc37054..11b16ec 100644
> > > --- a/drivers/pwm/pwm-img.c
> > > +++ b/drivers/pwm/pwm-img.c
> > > @@ -156,7 +156,7 @@ static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> > >       struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
> > >       int ret;
> > >
> > > -     ret = pm_runtime_get_sync(chip->dev);
> > > +     ret = pm_runtime_resume_and_get(chip->dev);
> > >       if (ret < 0)
> > >               return ret;
> >
> > This patch looks right with my limited understanding of pm_runtime. A
> > similar issue in this driver was fixed in commit
> >
> >         ca162ce98110 ("pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case")
> >
> > where (even though the commit log talks about pm_runtime_put()) a call
> > to pm_runtime_put_autosuspend() was added in the error path.
> >
> > I added the PM guys to Cc, maybe they can advise about the right thing
> > to do here. Does it make sense to use the same idiom in both
> > img_pwm_enable() and img_pwm_config()?
> 
> I think so.
> 
> And calling pm_runtime_put_autosuspend() in the img_pwm_enable() error
> path would work too.

Do you care to clean this up accordingly and send a new patch?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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Re: [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()

[Uwe Kleine-König]

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Hello Zou,
On Mon, Jun 28, 2021 at 08:38:39AM +0200, Uwe Kleine-König wrote:
> On Fri, Jun 25, 2021 at 07:45:14PM +0200, Rafael J. Wysocki wrote:
> > On Wed, May 12, 2021 at 6:52 AM Uwe Kleine-König
> > <u.kleine-koenig@pengutronix.de> wrote:
> > > On Wed, May 12, 2021 at 11:57:17AM +0800, Zou Wei 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@huawei.com>
> > > > Signed-off-by: Zou Wei <zou_wei@huawei.com>
> > > > ---
> > > >  drivers/pwm/pwm-img.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
> > > > index cc37054..11b16ec 100644
> > > > --- a/drivers/pwm/pwm-img.c
> > > > +++ b/drivers/pwm/pwm-img.c
> > > > @@ -156,7 +156,7 @@ static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> > > >       struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
> > > >       int ret;
> > > >
> > > > -     ret = pm_runtime_get_sync(chip->dev);
> > > > +     ret = pm_runtime_resume_and_get(chip->dev);
> > > >       if (ret < 0)
> > > >               return ret;
> > >
> > > This patch looks right with my limited understanding of pm_runtime. A
> > > similar issue in this driver was fixed in commit
> > >
> > >         ca162ce98110 ("pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case")
> > >
> > > where (even though the commit log talks about pm_runtime_put()) a call
> > > to pm_runtime_put_autosuspend() was added in the error path.
> > >
> > > I added the PM guys to Cc, maybe they can advise about the right thing
> > > to do here. Does it make sense to use the same idiom in both
> > > img_pwm_enable() and img_pwm_config()?
> > 
> > I think so.
> > 
> > And calling pm_runtime_put_autosuspend() in the img_pwm_enable() error
> > path would work too.
> 
> Do you care to clean this up accordingly and send a new patch?

Note that Thierry applied your initial patch regardless of the
inconsistency. Still I'd like to see this done in a consistent way. Do
you care to follow up with a patch that unifies the behaviour?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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Re: [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()

[Samuel Zou]

Hi Uwe,

Sorry for the delayed reply.
Thanks for all the review,.
To keep the consistency, it's better to clean this up accordingly, and I 
will send a new patch soon.

On 2021/6/29 1:01, Uwe Kleine-König wrote:
> Hello Zou,
> On Mon, Jun 28, 2021 at 08:38:39AM +0200, Uwe Kleine-König wrote:
>> On Fri, Jun 25, 2021 at 07:45:14PM +0200, Rafael J. Wysocki wrote:
>>> On Wed, May 12, 2021 at 6:52 AM Uwe Kleine-König
>>> <u.kleine-koenig@pengutronix.de> wrote:
>>>> On Wed, May 12, 2021 at 11:57:17AM +0800, Zou Wei 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@huawei.com>
>>>>> Signed-off-by: Zou Wei <zou_wei@huawei.com>
>>>>> ---
>>>>>   drivers/pwm/pwm-img.c | 2 +-
>>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
>>>>> index cc37054..11b16ec 100644
>>>>> --- a/drivers/pwm/pwm-img.c
>>>>> +++ b/drivers/pwm/pwm-img.c
>>>>> @@ -156,7 +156,7 @@ static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>>>>>        struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
>>>>>        int ret;
>>>>>
>>>>> -     ret = pm_runtime_get_sync(chip->dev);
>>>>> +     ret = pm_runtime_resume_and_get(chip->dev);
>>>>>        if (ret < 0)
>>>>>                return ret;
>>>>
>>>> This patch looks right with my limited understanding of pm_runtime. A
>>>> similar issue in this driver was fixed in commit
>>>>
>>>>          ca162ce98110 ("pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case")
>>>>
>>>> where (even though the commit log talks about pm_runtime_put()) a call
>>>> to pm_runtime_put_autosuspend() was added in the error path.
>>>>
>>>> I added the PM guys to Cc, maybe they can advise about the right thing
>>>> to do here. Does it make sense to use the same idiom in both
>>>> img_pwm_enable() and img_pwm_config()?
>>>
>>> I think so.
>>>
>>> And calling pm_runtime_put_autosuspend() in the img_pwm_enable() error
>>> path would work too.
>>
>> Do you care to clean this up accordingly and send a new patch?
> 
> Note that Thierry applied your initial patch regardless of the
> inconsistency. Still I'd like to see this done in a consistent way. Do
> you care to follow up with a patch that unifies the behaviour?
> 
> Best regards
> Uwe
>