From: "Rafael J. Wysocki" <rafael@kernel.org>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Zou Wei <zou_wei@huawei.com>,
Thierry Reding <thierry.reding@gmail.com>,
Lee Jones <lee.jones@linaro.org>,
Linux PWM List <linux-pwm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Kevin Hilman <khilman@kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Linux PM <linux-pm@vger.kernel.org>
Subject: Re: [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()
Date: Fri, 25 Jun 2021 19:45:14 +0200 [thread overview]
Message-ID: <CAJZ5v0huz6Ek1FTvdMs0hPOoMn+ZHiNJeDp6-ujg-1WwpCsELQ@mail.gmail.com> (raw)
In-Reply-To: <20210512045222.2yjm6yxikznohlmn@pengutronix.de>
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.
next prev parent reply other threads:[~2021-06-25 17:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 3:57 [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable() Zou Wei
2021-05-12 4:52 ` Uwe Kleine-König
2021-06-25 17:33 ` Uwe Kleine-König
2021-06-25 17:45 ` Rafael J. Wysocki [this message]
2021-06-28 6:38 ` Uwe Kleine-König
2021-06-28 17:01 ` Uwe Kleine-König
2021-06-29 3:23 ` Samuel Zou
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