| Message ID | 20170714120720.906842-19-arnd@arndb.de |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, 2017-07-14 at 14:07 +0200, Arnd Bergmann wrote: > gcc-7 notices that the pin_table is an array of 16-bit numbers, > but we assume it can be printed as a two-character hexadecimal > string: > > 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); > ~~~~ This is obviously a false positive warning. Here we have int pin = u16 pin_table[0] <= 255 (implying >= 0). I see few options how to make it more clear 1) your proposal; 2) use "%02hhX" instead; 3) use if (ret >= 0 && ret <= 255) condition. I would choose one of the 2-3. In case gcc will complain about 3), file a bug to gcc crazy warning. > > This can't be right, so this changes it to truncate the number to > an 8-bit pin number. > > Fixes: 0d1c28a449c6 ("gpiolib-acpi: Add ACPI5 event model support to > gpio.") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/gpio/gpiolib-acpi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c > index c9b42dd12dfa..c3faea724af8 100644 > --- a/drivers/gpio/gpiolib-acpi.c > +++ b/drivers/gpio/gpiolib-acpi.c > @@ -205,7 +205,7 @@ static acpi_status > acpi_gpiochip_request_interrupt(struct acpi_resource *ares, > char ev_name[5]; > sprintf(ev_name, "_%c%02X", > agpio->triggering == ACPI_EDGE_SENSITIVE ? > 'E' : 'L', > - pin); > + (u8)pin); > if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, > &evt_handle))) > handler = acpi_gpio_irq_handler; > }
On Fri, Jul 14, 2017 at 2:52 PM, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > On Fri, 2017-07-14 at 14:07 +0200, Arnd Bergmann wrote: >> gcc-7 notices that the pin_table is an array of 16-bit numbers, >> but we assume it can be printed as a two-character hexadecimal >> string: >> >> 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); >> ~~~~ > > > This is obviously a false positive warning. > > Here we have > int pin = u16 pin_table[0] <= 255 (implying >= 0). > > I see few options how to make it more clear > 1) your proposal; > 2) use "%02hhX" instead; > 3) use if (ret >= 0 && ret <= 255) condition. > > I would choose one of the 2-3. > > In case gcc will complain about 3), file a bug to gcc crazy warning. Makes sense. I didn't remember the syntax for 2) and couldn't find it in the man page when I first looked. This seems like a good solution here. I'm pretty sure I tried 3) a few times when the warning first showed up last year, but couldn't get that to work. Filing a gcc bug also seems like a good idea, but I should first see if it's already fixed. The version I use for testing at the moment is from late April, and others may have complained about that already. Arnd
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c index c9b42dd12dfa..c3faea724af8 100644 --- a/drivers/gpio/gpiolib-acpi.c +++ b/drivers/gpio/gpiolib-acpi.c @@ -205,7 +205,7 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares, char ev_name[5]; sprintf(ev_name, "_%c%02X", agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L', - pin); + (u8)pin); if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle))) handler = acpi_gpio_irq_handler; }
gcc-7 notices that the pin_table is an array of 16-bit numbers, but we assume it can be printed as a two-character hexadecimal string: 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); ~~~~ This can't be right, so this changes it to truncate the number to an 8-bit pin number. Fixes: 0d1c28a449c6 ("gpiolib-acpi: Add ACPI5 event model support to gpio.") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/gpio/gpiolib-acpi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)