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From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Schrempf Frieder <frieder.schrempf@kontron.de>
Cc: "shawnguo@kernel.org" <shawnguo@kernel.org>,
	"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	"festevam@gmail.com" <festevam@gmail.com>,
	"linux-imx@nxp.com" <linux-imx@nxp.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"geert+renesas@glider.be" <geert+renesas@glider.be>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
	Jiri Slaby <jslaby@suse.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3 2/4] serial: mctrl_gpio: Add a NULL check to mctrl_gpio_to_gpiod()
Date: Fri, 2 Aug 2019 14:12:31 +0200	[thread overview]
Message-ID: <20190802121231.wk6yg5mkyivs3rni@pengutronix.de> (raw)
In-Reply-To: <20190802100349.8659-2-frieder.schrempf@kontron.de>

On Fri, Aug 02, 2019 at 10:04:10AM +0000, Schrempf Frieder wrote:
> From: Frieder Schrempf <frieder.schrempf@kontron.de>
> 
> As it is allowed to use the mctrl_gpio_* functions before
> initialization (as the 8250 driver does according to 434be0ae7aa7),

Actually I was surprised some time ago that 8250 used serial_mctrl
without first initializing it and expecting it to work. I didn't look in
detail, but I wouldn't go so far to call this "allowed". The commit
itself calls it "workaround" which seems a better match.

> it seems appropriate to have a NULL check in all of the functions.
> Otherwise the mctrl_gpio_to_gpiod() function is prone to be used
> in a context that can lead to a NULL pointer dereference.
> 
> Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>

Best regards
Uwe

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

WARNING: multiple messages have this Message-ID (diff)
From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Schrempf Frieder <frieder.schrempf@kontron.de>
Cc: "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
	"geert+renesas@glider.be" <geert+renesas@glider.be>,
	"shawnguo@kernel.org" <shawnguo@kernel.org>,
	"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
	Jiri Slaby <jslaby@suse.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-imx@nxp.com" <linux-imx@nxp.com>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"festevam@gmail.com" <festevam@gmail.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3 2/4] serial: mctrl_gpio: Add a NULL check to mctrl_gpio_to_gpiod()
Date: Fri, 2 Aug 2019 14:12:31 +0200	[thread overview]
Message-ID: <20190802121231.wk6yg5mkyivs3rni@pengutronix.de> (raw)
In-Reply-To: <20190802100349.8659-2-frieder.schrempf@kontron.de>

On Fri, Aug 02, 2019 at 10:04:10AM +0000, Schrempf Frieder wrote:
> From: Frieder Schrempf <frieder.schrempf@kontron.de>
> 
> As it is allowed to use the mctrl_gpio_* functions before
> initialization (as the 8250 driver does according to 434be0ae7aa7),

Actually I was surprised some time ago that 8250 used serial_mctrl
without first initializing it and expecting it to work. I didn't look in
detail, but I wouldn't go so far to call this "allowed". The commit
itself calls it "workaround" which seems a better match.

> it seems appropriate to have a NULL check in all of the functions.
> Otherwise the mctrl_gpio_to_gpiod() function is prone to be used
> in a context that can lead to a NULL pointer dereference.
> 
> Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>

Best regards
Uwe

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

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  reply	other threads:[~2019-08-02 12:12 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 10:04 [PATCH v3 1/4] serial: mctrl_gpio: Avoid probe failures in case of missing gpiolib Schrempf Frieder
2019-08-02 10:04 ` Schrempf Frieder
2019-08-02 10:04 ` Schrempf Frieder
2019-08-02 10:04 ` [PATCH v3 2/4] serial: mctrl_gpio: Add a NULL check to mctrl_gpio_to_gpiod() Schrempf Frieder
2019-08-02 10:04   ` Schrempf Frieder
2019-08-02 10:04   ` Schrempf Frieder
2019-08-02 12:12   ` Uwe Kleine-König [this message]
2019-08-02 12:12     ` Uwe Kleine-König
2019-08-02 12:12     ` Uwe Kleine-König
2019-08-05  9:01     ` Schrempf Frieder
2019-08-05  9:01       ` Schrempf Frieder
2019-08-05  9:01       ` Schrempf Frieder
2019-08-06  7:45       ` Uwe Kleine-König
2019-08-06  7:45         ` Uwe Kleine-König
2019-08-06  7:45         ` Uwe Kleine-König
2019-08-06  8:02         ` Schrempf Frieder
2019-08-06  8:02           ` Schrempf Frieder
2019-08-06  8:02           ` Schrempf Frieder
2019-08-02 10:04 ` [PATCH v3 3/4] serial: sh-sci: Don't check for mctrl_gpio_init() returning -ENOSYS Schrempf Frieder
2019-08-02 10:04   ` Schrempf Frieder
2019-08-02 10:04   ` Schrempf Frieder
2019-08-02 12:13   ` Uwe Kleine-König
2019-08-02 12:13     ` Uwe Kleine-König
2019-08-02 12:13     ` Uwe Kleine-König
2019-08-06  8:09   ` Geert Uytterhoeven
2019-08-06  8:09     ` Geert Uytterhoeven
2019-08-06  8:09     ` Geert Uytterhoeven
2019-08-02 10:04 ` [PATCH v3 4/4] serial: 8250: " Schrempf Frieder
2019-08-02 10:04   ` Schrempf Frieder
2019-08-02 10:04   ` Schrempf Frieder
2019-08-02 12:15   ` Uwe Kleine-König
2019-08-02 12:15     ` Uwe Kleine-König
2019-08-02 12:15     ` Uwe Kleine-König
2019-08-02 12:26     ` Greg Kroah-Hartman
2019-08-02 12:26       ` Greg Kroah-Hartman
2019-08-02 12:26       ` Greg Kroah-Hartman
2019-08-06  7:44       ` Uwe Kleine-König
2019-08-06  7:44         ` Uwe Kleine-König
2019-08-06  7:44         ` Uwe Kleine-König
2019-08-02 12:08 ` [PATCH v3 1/4] serial: mctrl_gpio: Avoid probe failures in case of missing gpiolib Uwe Kleine-König
2019-08-02 12:08   ` Uwe Kleine-König
2019-08-02 12:08   ` Uwe Kleine-König
2019-08-06  8:09 ` Geert Uytterhoeven
2019-08-06  8:09   ` Geert Uytterhoeven
2019-08-06  8:09   ` Geert Uytterhoeven

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