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From: Matthias Kaehlcke <mka@chromium.org>
To: Leonard Crestez <leonard.crestez@nxp.com>
Cc: "MyungJoo Ham" <myungjoo.ham@samsung.com>,
	"Kyungmin Park" <kyungmin.park@samsung.com>,
	"Chanwoo Choi" <cw00.choi@samsung.com>,
	"Artur Świgoń" <a.swigon@partner.samsung.com>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Lukasz Luba" <l.luba@partner.samsung.com>,
	linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] PM / devfreq: Check NULL governor in available_governors_show
Date: Mon, 23 Sep 2019 11:50:47 -0700	[thread overview]
Message-ID: <20190923185047.GC133864@google.com> (raw)
In-Reply-To: <96f459015e6418cee4fa20fdbdb80c4caf417c19.1569256298.git.leonard.crestez@nxp.com>

On Mon, Sep 23, 2019 at 07:34:43PM +0300, Leonard Crestez wrote:
> The governor is initialized after sysfs attributes become visible so in
> theory the governor field can be NULL here.
> 
> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
> ---
>  drivers/devfreq/devfreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Found this by hacking device core to call attribute "show" functions
> from inside device_add.
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 00fc23fea5b2..896fb2312f2f 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -1322,11 +1322,11 @@ static ssize_t available_governors_show(struct device *d,
>  
>  	/*
>  	 * The devfreq with immutable governor (e.g., passive) shows
>  	 * only own governor.
>  	 */
> -	if (df->governor->immutable) {
> +	if (df->governor && df->governor->immutable) {
>  		count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
>  				  "%s ", df->governor_name);
>  	/*
>  	 * The devfreq device shows the registered governor except for
>  	 * immutable governors such as passive governor .

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

WARNING: multiple messages have this Message-ID (diff)
From: Matthias Kaehlcke <mka@chromium.org>
To: Leonard Crestez <leonard.crestez@nxp.com>
Cc: "Artur Świgoń" <a.swigon@partner.samsung.com>,
	linux-pm@vger.kernel.org, "Krzysztof Kozlowski" <krzk@kernel.org>,
	"Lukasz Luba" <l.luba@partner.samsung.com>,
	"Chanwoo Choi" <cw00.choi@samsung.com>,
	"Kyungmin Park" <kyungmin.park@samsung.com>,
	"MyungJoo Ham" <myungjoo.ham@samsung.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] PM / devfreq: Check NULL governor in available_governors_show
Date: Mon, 23 Sep 2019 11:50:47 -0700	[thread overview]
Message-ID: <20190923185047.GC133864@google.com> (raw)
In-Reply-To: <96f459015e6418cee4fa20fdbdb80c4caf417c19.1569256298.git.leonard.crestez@nxp.com>

On Mon, Sep 23, 2019 at 07:34:43PM +0300, Leonard Crestez wrote:
> The governor is initialized after sysfs attributes become visible so in
> theory the governor field can be NULL here.
> 
> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
> ---
>  drivers/devfreq/devfreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Found this by hacking device core to call attribute "show" functions
> from inside device_add.
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 00fc23fea5b2..896fb2312f2f 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -1322,11 +1322,11 @@ static ssize_t available_governors_show(struct device *d,
>  
>  	/*
>  	 * The devfreq with immutable governor (e.g., passive) shows
>  	 * only own governor.
>  	 */
> -	if (df->governor->immutable) {
> +	if (df->governor && df->governor->immutable) {
>  		count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
>  				  "%s ", df->governor_name);
>  	/*
>  	 * The devfreq device shows the registered governor except for
>  	 * immutable governors such as passive governor .

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

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linux-arm-kernel@lists.infradead.org
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  reply	other threads:[~2019-09-23 18:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20190923163453epcas4p1f9cff7d9f1a33fabcf4c980560d6c27d@epcas4p1.samsung.com>
2019-09-23 16:34 ` [PATCH] PM / devfreq: Check NULL governor in available_governors_show Leonard Crestez
2019-09-23 16:34   ` Leonard Crestez
2019-09-23 18:50   ` Matthias Kaehlcke [this message]
2019-09-23 18:50     ` Matthias Kaehlcke
2019-09-24  1:52   ` Chanwoo Choi
2019-09-24  1:52     ` Chanwoo Choi
2019-09-24  7:17     ` Leonard Crestez
2019-09-24  7:17       ` Leonard Crestez
2019-09-24  7:25       ` Chanwoo Choi
2019-09-24  7:25         ` Chanwoo Choi

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