From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Zou Wei <zou_wei@huawei.com>
Cc: thierry.reding@gmail.com, lee.jones@linaro.org,
linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Kevin Hilman <khilman@kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
linux-pm@vger.kernel.org
Subject: Re: [PATCH -next] pwm: img: Fix PM reference leak in img_pwm_enable()
Date: Wed, 12 May 2021 06:52:22 +0200 [thread overview]
Message-ID: <20210512045222.2yjm6yxikznohlmn@pengutronix.de> (raw)
In-Reply-To: <1620791837-16138-1-git-send-email-zou_wei@huawei.com>
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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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next prev parent reply other threads:[~2021-05-12 4:52 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 [this message]
2021-06-25 17:33 ` Uwe Kleine-König
2021-06-25 17:45 ` Rafael J. Wysocki
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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