From: Joe Perches <joe@perches.com>
To: Arnd Bergmann <arnd@arndb.de>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Linus Walleij <linus.walleij@linaro.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Hans de Goede <hdegoede@redhat.com>,
Wei Yongjun <weiyongjun1@huawei.com>,
linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] gpio: acpi: work around false-positive -Wstring-overflow warning
Date: Wed, 06 Sep 2017 08:52:53 -0700 [thread overview]
Message-ID: <1504713173.7546.3.camel@perches.com> (raw)
In-Reply-To: <20170906154756.2133726-1-arnd@arndb.de>
On Wed, 2017-09-06 at 17:47 +0200, Arnd Bergmann wrote:
> gcc-7 notices that the pin_table is an array of 16-bit numbers,
> but fails to take the following range check into account:
>
> drivers/gpio/gpiolib-acpi.c: In function 'acpi_gpiochip_request_interrupt':
> drivers/gpio/gpiolib-acpi.c:206:24: warning: '%02X' directive writing between 2 and 4 bytes into a region of size 3 [-Wformat-overflow=]
> sprintf(ev_name, "_%c%02X",
> ^~~~
> drivers/gpio/gpiolib-acpi.c:206:20: note: directive argument in the range [0, 65535]
> sprintf(ev_name, "_%c%02X",
> ^~~~~~~~~
> drivers/gpio/gpiolib-acpi.c:206:3: note: 'sprintf' output between 5 and 7 bytes into a destination of size 5
> sprintf(ev_name, "_%c%02X",
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> pin);
> ~~~~
>
> As suggested by Andy, this changes the format string to have a fixed length.
> Since modifying the range check did not help, I also opened a bug against
> gcc, see link below.
The code has
int pin
does changing pin to unsigned int matter?
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
[]
> @@ -203,7 +203,7 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
>
> if (pin <= 255) {
> char ev_name[5];
> - sprintf(ev_name, "_%c%02X",
> + sprintf(ev_name, "_%c%02hhX",
> agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
> pin);
> if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
next prev parent reply other threads:[~2017-09-06 15:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-06 15:47 [PATCH] gpio: acpi: work around false-positive -Wstring-overflow warning Arnd Bergmann
2017-09-06 15:52 ` Joe Perches [this message]
2017-09-06 19:53 ` Arnd Bergmann
2017-09-06 23:42 ` Joe Perches
2017-09-07 6:50 ` Mika Westerberg
2017-09-12 9:26 ` Linus Walleij
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