From: Schrempf Frieder <frieder.schrempf@kontron.de>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.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: Mon, 5 Aug 2019 09:01:39 +0000 [thread overview]
Message-ID: <f866213b-fd3b-8602-6c11-56cb65a1ea05@kontron.de> (raw)
In-Reply-To: <20190802121231.wk6yg5mkyivs3rni@pengutronix.de>
On 02.08.19 14:12, Uwe Kleine-König wrote:
> 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.
Ok, but if this is considered to be a workaround and as the 8250 driver
does not use mctrl_gpio_to_gpiod(), we should maybe just drop this patch
instead of encouraging others to use mctrl_gpio before initialization.
I'm really not sure what's best, so depending on what you will propose,
I'll send a new version of this patch with adjusted commit message or not.
By the way, Uwe and Fabio: Thanks for your reviews!
>
>> 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
>
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next prev parent reply other threads:[~2019-08-05 9:01 UTC|newest]
Thread overview: 15+ 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 ` [PATCH v3 2/4] serial: mctrl_gpio: Add a NULL check to mctrl_gpio_to_gpiod() Schrempf Frieder
2019-08-02 12:12 ` Uwe Kleine-König
2019-08-05 9:01 ` Schrempf Frieder [this message]
2019-08-06 7:45 ` Uwe Kleine-König
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 12:13 ` Uwe Kleine-König
2019-08-06 8:09 ` Geert Uytterhoeven
2019-08-02 10:04 ` [PATCH v3 4/4] serial: 8250: " Schrempf Frieder
2019-08-02 12:15 ` Uwe Kleine-König
2019-08-02 12:26 ` Greg Kroah-Hartman
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
2019-08-06 8:09 ` Geert Uytterhoeven
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